使用mybatis生成器生成实体类mapper和查询参数文件，简单spring mvc 项目。使用log4j输出日志到控制台和文件中。使用配置文件注册Bean

项目概况

这是一个基于Spring + SpringMVC + MyBatis框架demo。采用MVC架构设计，主要功能是对两个表的增删改查。

项目分为控制层(Controller)、实体层(Entity)、数据访问层(Mapper)和业务逻辑层(Service)，符合标准的分层架构设计。

主要配置文件作用

1. 代码生成配置文件: generatorConfig.xml
   generatorConfig.xml 是MyBatis Generator的配置文件，主要用于自动生成项目中的实体类、Mapper接口和Mapper XML文件。

核心功能:

• 配置数据库连接信息(驱动、URL、用户名、密码)

• 指定实体类生成的包路径和项目位置

• 配置Mapper接口和XML映射文件的生成路径

• 定义要生成的数据库表与实体类的对应关系

• 设置生成策略(如是否使用实际列名、是否抑制注释等)
  关键配置项:

• <table> 标签: 指定数据库表名和对应的实体类名

• <javaModelGenerator> : 配置实体类生成策略

• <sqlMapGenerator> : 配置Mapper XML文件生成策略

• <javaClientGenerator> : 配置Mapper接口生成策略
  这个文件极大地减少了开发人员的重复工作，通过自动生成基础代码，提高了开发效率。

2. 日志配置文件: log4j.properties
   log4j.properties 是Log4j日志框架的配置文件，用于控制日志的输出级别、格式和目的地。

核心功能:

• 设置根日志级别(DEBUG)

• 配置日志输出到控制台

• 定义日志输出格式(包含时间戳、线程、日志级别、类名等信息)

• 对不同包或类设置不同的日志级别
  关键配置项:

• log4j.rootLogger : 设置根日志级别和输出目的地

• log4j.appender.Console : 配置控制台输出

• log4j.appender.Console.layout : 设置日志输出格式

• 针对特定包的日志级别设置(如 java.sql.ResultSet=INFO )
  这个文件帮助开发人员在开发和调试过程中更好地跟踪系统运行状态，排查问题。

3. 其他重要配置文件

• applicationContext.xml : Spring框架的核心配置文件，配置数据源、事务管理、包扫描等
• springmvc.xml : SpringMVC配置文件，配置控制器扫描、视图解析器等
• db.properties : 数据库连接配置文件，存储数据库URL、用户名和密码
• SqlMapConfig.xml : MyBatis核心配置文件(未在本次查看范围内)
  这些配置文件共同构成了项目的基础配置，确保系统各组件能够正确协同工作。

访问: http://127.0.0.1:8080/list 可看到日志情况

目录结构

├── pom.xml
└── src\
    └── main\
        ├── java\
        │   └── com\
        │       └── demo\
        │           ├── controller\
        │           │   └── EmployeeController.java
        │           ├── entity\
        │           │   ├── Depart.java
        │           │   ├── DepartExample.java
        │           │   ├── Employee.java
        │           │   └── EmployeeExample.java
        │           ├── mapper\
        │           │   ├── DepartMapper.java
        │           │   ├── DepartMapper.xml
        │           │   ├── EmployeeMapper.java
        │           │   └── EmployeeMapper.xml
        │           └── service\
        │               ├── EmployeeService.java
        │               └── impl\
        │                   └── EmployeeServiceImpl.java
        ├── resources\
        │   ├── SqlMapConfig.xml
        │   ├── applicationContext.xml
        │   ├── db.properties
        │   ├── generatorConfig.xml
        │   ├── log4j.properties
        │   └── springmvc.xml
        └── webapp\
            ├── WEB-INF\
            │   ├── jsp\
            │   └── web.xml
            └── index.jsp

创建表sql

-- 先执行 depart 
CREATE TABLE depart (
  depid INT PRIMARY KEY AUTO_INCREMENT,
  depname VARCHAR(255) NOT NULL
);



CREATE TABLE employee (
  empid INT PRIMARY KEY AUTO_INCREMENT,
  empname VARCHAR(255) NOT NULL,
  bsaralry DOUBLE,
  hiredate DATE,
  address VARCHAR(255),
  depid INT,
  FOREIGN KEY (depid) REFERENCES depart(depid)
);

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.demo</groupId>
    <artifactId>empsys</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>empsys Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <junit.version>4.12</junit.version>
        <spring.version>4.2.4.RELEASE</spring.version>
        <mybatis.version>3.2.8</mybatis.version>
        <mybatis.spring.version>1.2.2</mybatis.spring.version>
        <mybatis.paginator.version>1.2.15</mybatis.paginator.version>
        <mysql.version>8.0.33</mysql.version>
        <slf4j.version>1.6.4</slf4j.version>
        <jackson.version>2.4.2</jackson.version>
        <druid.version>1.0.9</druid.version>
        <jstl.version>1.2</jstl.version>
        <servlet-api.version>2.5</servlet-api.version>
        <jsp-api.version>2.0</jsp-api.version>
        <commons-lang3.version>3.3.2</commons-lang3.version>
        <commons-io.version>1.3.2</commons-io.version>
        <commons-net.version>3.3</commons-net.version>
        <pagehelper.version>5.1.2</pagehelper.version>
        <commons-fileupload.version>1.3.1</commons-fileupload.version>
    </properties>

    <dependencies>
        <!-- Apache工具组件 -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>

        <dependency>
            <groupId>commons-net</groupId>
            <artifactId>commons-net</artifactId>
            <version>${commons-net.version}</version>
        </dependency>
        <!-- Jackson Json处理工具包 -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <!-- 单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <!-- 日志处理 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- Mybatis框架 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>${mybatis.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>${mybatis.spring.version}</version>
        </dependency>

        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>${pagehelper.version}</version>
        </dependency>
        <!-- MySql数据库 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <!-- 阿里巴巴连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>
        <!-- Spring支持 -->
        <!-- IOC容器 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 扩展IOC容器，添加任务调度 邮件服务等 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- spring mvc框架 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- spring context的扩展，用于mvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- spring jdbc的简单封装 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 面向切面编程 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- JSP相关 -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>${servlet-api.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jsp-api</artifactId>
            <version>${jsp-api.version}</version>
            <scope>provided</scope>
        </dependency>
        <!-- 文件上传组件 -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>${commons-fileupload.version}</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>${commons-io.version}</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>empsys</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <!-- 虚拟路径-->
                    <path>/</path>
                    <port>8080</port>
                </configuration>
            </plugin>
            <plugin>
                <!--mybatis的DAO接口和映射配置文件EmployeeMapper.xml代码自动生成-->
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.*</include>
                </includes>
            </resource>
        </resources>
    </build>
</project>

实体类

public class Depart {
    private Integer depid;

    private String depname;
    /* 忽略get set */
}


public class Employee {
    private Integer empid;

    private String empname;

    private Double bsaralry;

    private Date hiredate;

    private String address;

    private Integer depid;
    /* 忽略get set */
}

mapper用到的查询条件类

可以看到封装了很多查询sql条件。

import java.util.ArrayList;
import java.util.List;

public class DepartExample {
    protected String orderByClause;

    protected boolean distinct;

    protected List<Criteria> oredCriteria;

    public DepartExample() {
        oredCriteria = new ArrayList<Criteria>();
    }

    public void setOrderByClause(String orderByClause) {
        this.orderByClause = orderByClause;
    }

    public String getOrderByClause() {
        return orderByClause;
    }

    public void setDistinct(boolean distinct) {
        this.distinct = distinct;
    }

    public boolean isDistinct() {
        return distinct;
    }

    public List<Criteria> getOredCriteria() {
        return oredCriteria;
    }

    public void or(Criteria criteria) {
        oredCriteria.add(criteria);
    }

    public Criteria or() {
        Criteria criteria = createCriteriaInternal();
        oredCriteria.add(criteria);
        return criteria;
    }

    public Criteria createCriteria() {
        Criteria criteria = createCriteriaInternal();
        if (oredCriteria.size() == 0) {
            oredCriteria.add(criteria);
        }
        return criteria;
    }

    protected Criteria createCriteriaInternal() {
        Criteria criteria = new Criteria();
        return criteria;
    }

    public void clear() {
        oredCriteria.clear();
        orderByClause = null;
        distinct = false;
    }

    protected abstract static class GeneratedCriteria {
        protected List<Criterion> criteria;

        protected GeneratedCriteria() {
            super();
            criteria = new ArrayList<Criterion>();
        }

        public boolean isValid() {
            return criteria.size() > 0;
        }

        public List<Criterion> getAllCriteria() {
            return criteria;
        }

        public List<Criterion> getCriteria() {
            return criteria;
        }

        protected void addCriterion(String condition) {
            if (condition == null) {
                throw new RuntimeException("Value for condition cannot be null");
            }
            criteria.add(new Criterion(condition));
        }

        protected void addCriterion(String condition, Object value, String property) {
            if (value == null) {
                throw new RuntimeException("Value for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value));
        }

        protected void addCriterion(String condition, Object value1, Object value2, String property) {
            if (value1 == null || value2 == null) {
                throw new RuntimeException("Between values for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value1, value2));
        }

        public Criteria andDepidIsNull() {
            addCriterion("depid is null");
            return (Criteria) this;
        }

        public Criteria andDepidIsNotNull() {
            addCriterion("depid is not null");
            return (Criteria) this;
        }

        public Criteria andDepidEqualTo(Integer value) {
            addCriterion("depid =", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotEqualTo(Integer value) {
            addCriterion("depid <>", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidGreaterThan(Integer value) {
            addCriterion("depid >", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidGreaterThanOrEqualTo(Integer value) {
            addCriterion("depid >=", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidLessThan(Integer value) {
            addCriterion("depid <", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidLessThanOrEqualTo(Integer value) {
            addCriterion("depid <=", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidIn(List<Integer> values) {
            addCriterion("depid in", values, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotIn(List<Integer> values) {
            addCriterion("depid not in", values, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidBetween(Integer value1, Integer value2) {
            addCriterion("depid between", value1, value2, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotBetween(Integer value1, Integer value2) {
            addCriterion("depid not between", value1, value2, "depid");
            return (Criteria) this;
        }

        public Criteria andDepnameIsNull() {
            addCriterion("depname is null");
            return (Criteria) this;
        }

        public Criteria andDepnameIsNotNull() {
            addCriterion("depname is not null");
            return (Criteria) this;
        }

        public Criteria andDepnameEqualTo(String value) {
            addCriterion("depname =", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameNotEqualTo(String value) {
            addCriterion("depname <>", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameGreaterThan(String value) {
            addCriterion("depname >", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameGreaterThanOrEqualTo(String value) {
            addCriterion("depname >=", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameLessThan(String value) {
            addCriterion("depname <", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameLessThanOrEqualTo(String value) {
            addCriterion("depname <=", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameLike(String value) {
            addCriterion("depname like", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameNotLike(String value) {
            addCriterion("depname not like", value, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameIn(List<String> values) {
            addCriterion("depname in", values, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameNotIn(List<String> values) {
            addCriterion("depname not in", values, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameBetween(String value1, String value2) {
            addCriterion("depname between", value1, value2, "depname");
            return (Criteria) this;
        }

        public Criteria andDepnameNotBetween(String value1, String value2) {
            addCriterion("depname not between", value1, value2, "depname");
            return (Criteria) this;
        }
    }

    public static class Criteria extends GeneratedCriteria {

        protected Criteria() {
            super();
        }
    }

    public static class Criterion {
        private String condition;

        private Object value;

        private Object secondValue;

        private boolean noValue;

        private boolean singleValue;

        private boolean betweenValue;

        private boolean listValue;

        private String typeHandler;

        public String getCondition() {
            return condition;
        }

        public Object getValue() {
            return value;
        }

        public Object getSecondValue() {
            return secondValue;
        }

        public boolean isNoValue() {
            return noValue;
        }

        public boolean isSingleValue() {
            return singleValue;
        }

        public boolean isBetweenValue() {
            return betweenValue;
        }

        public boolean isListValue() {
            return listValue;
        }

        public String getTypeHandler() {
            return typeHandler;
        }

        protected Criterion(String condition) {
            super();
            this.condition = condition;
            this.typeHandler = null;
            this.noValue = true;
        }

        protected Criterion(String condition, Object value, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.typeHandler = typeHandler;
            if (value instanceof List<?>) {
                this.listValue = true;
            } else {
                this.singleValue = true;
            }
        }

        protected Criterion(String condition, Object value) {
            this(condition, value, null);
        }

        protected Criterion(String condition, Object value, Object secondValue, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.secondValue = secondValue;
            this.typeHandler = typeHandler;
            this.betweenValue = true;
        }

        protected Criterion(String condition, Object value, Object secondValue) {
            this(condition, value, secondValue, null);
        }
    }
}


import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

public class EmployeeExample {
    protected String orderByClause;

    protected boolean distinct;

    protected List<Criteria> oredCriteria;

    public EmployeeExample() {
        oredCriteria = new ArrayList<Criteria>();
    }

    public void setOrderByClause(String orderByClause) {
        this.orderByClause = orderByClause;
    }

    public String getOrderByClause() {
        return orderByClause;
    }

    public void setDistinct(boolean distinct) {
        this.distinct = distinct;
    }

    public boolean isDistinct() {
        return distinct;
    }

    public List<Criteria> getOredCriteria() {
        return oredCriteria;
    }

    public void or(Criteria criteria) {
        oredCriteria.add(criteria);
    }

    public Criteria or() {
        Criteria criteria = createCriteriaInternal();
        oredCriteria.add(criteria);
        return criteria;
    }

    public Criteria createCriteria() {
        Criteria criteria = createCriteriaInternal();
        if (oredCriteria.size() == 0) {
            oredCriteria.add(criteria);
        }
        return criteria;
    }

    protected Criteria createCriteriaInternal() {
        Criteria criteria = new Criteria();
        return criteria;
    }

    public void clear() {
        oredCriteria.clear();
        orderByClause = null;
        distinct = false;
    }

    protected abstract static class GeneratedCriteria {
        protected List<Criterion> criteria;

        protected GeneratedCriteria() {
            super();
            criteria = new ArrayList<Criterion>();
        }

        public boolean isValid() {
            return criteria.size() > 0;
        }

        public List<Criterion> getAllCriteria() {
            return criteria;
        }

        public List<Criterion> getCriteria() {
            return criteria;
        }

        protected void addCriterion(String condition) {
            if (condition == null) {
                throw new RuntimeException("Value for condition cannot be null");
            }
            criteria.add(new Criterion(condition));
        }

        protected void addCriterion(String condition, Object value, String property) {
            if (value == null) {
                throw new RuntimeException("Value for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value));
        }

        protected void addCriterion(String condition, Object value1, Object value2, String property) {
            if (value1 == null || value2 == null) {
                throw new RuntimeException("Between values for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value1, value2));
        }

        protected void addCriterionForJDBCDate(String condition, Date value, String property) {
            if (value == null) {
                throw new RuntimeException("Value for " + property + " cannot be null");
            }
            addCriterion(condition, new java.sql.Date(value.getTime()), property);
        }

        protected void addCriterionForJDBCDate(String condition, List<Date> values, String property) {
            if (values == null || values.size() == 0) {
                throw new RuntimeException("Value list for " + property + " cannot be null or empty");
            }
            List<java.sql.Date> dateList = new ArrayList<java.sql.Date>();
            Iterator<Date> iter = values.iterator();
            while (iter.hasNext()) {
                dateList.add(new java.sql.Date(iter.next().getTime()));
            }
            addCriterion(condition, dateList, property);
        }

        protected void addCriterionForJDBCDate(String condition, Date value1, Date value2, String property) {
            if (value1 == null || value2 == null) {
                throw new RuntimeException("Between values for " + property + " cannot be null");
            }
            addCriterion(condition, new java.sql.Date(value1.getTime()), new java.sql.Date(value2.getTime()), property);
        }

        public Criteria andEmpidIsNull() {
            addCriterion("empid is null");
            return (Criteria) this;
        }

        public Criteria andEmpidIsNotNull() {
            addCriterion("empid is not null");
            return (Criteria) this;
        }

        public Criteria andEmpidEqualTo(Integer value) {
            addCriterion("empid =", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidNotEqualTo(Integer value) {
            addCriterion("empid <>", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidGreaterThan(Integer value) {
            addCriterion("empid >", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidGreaterThanOrEqualTo(Integer value) {
            addCriterion("empid >=", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidLessThan(Integer value) {
            addCriterion("empid <", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidLessThanOrEqualTo(Integer value) {
            addCriterion("empid <=", value, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidIn(List<Integer> values) {
            addCriterion("empid in", values, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidNotIn(List<Integer> values) {
            addCriterion("empid not in", values, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidBetween(Integer value1, Integer value2) {
            addCriterion("empid between", value1, value2, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpidNotBetween(Integer value1, Integer value2) {
            addCriterion("empid not between", value1, value2, "empid");
            return (Criteria) this;
        }

        public Criteria andEmpnameIsNull() {
            addCriterion("empname is null");
            return (Criteria) this;
        }

        public Criteria andEmpnameIsNotNull() {
            addCriterion("empname is not null");
            return (Criteria) this;
        }

        public Criteria andEmpnameEqualTo(String value) {
            addCriterion("empname =", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameNotEqualTo(String value) {
            addCriterion("empname <>", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameGreaterThan(String value) {
            addCriterion("empname >", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameGreaterThanOrEqualTo(String value) {
            addCriterion("empname >=", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameLessThan(String value) {
            addCriterion("empname <", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameLessThanOrEqualTo(String value) {
            addCriterion("empname <=", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameLike(String value) {
            addCriterion("empname like", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameNotLike(String value) {
            addCriterion("empname not like", value, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameIn(List<String> values) {
            addCriterion("empname in", values, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameNotIn(List<String> values) {
            addCriterion("empname not in", values, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameBetween(String value1, String value2) {
            addCriterion("empname between", value1, value2, "empname");
            return (Criteria) this;
        }

        public Criteria andEmpnameNotBetween(String value1, String value2) {
            addCriterion("empname not between", value1, value2, "empname");
            return (Criteria) this;
        }

        public Criteria andBsaralryIsNull() {
            addCriterion("bsaralry is null");
            return (Criteria) this;
        }

        public Criteria andBsaralryIsNotNull() {
            addCriterion("bsaralry is not null");
            return (Criteria) this;
        }

        public Criteria andBsaralryEqualTo(Double value) {
            addCriterion("bsaralry =", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryNotEqualTo(Double value) {
            addCriterion("bsaralry <>", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryGreaterThan(Double value) {
            addCriterion("bsaralry >", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryGreaterThanOrEqualTo(Double value) {
            addCriterion("bsaralry >=", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryLessThan(Double value) {
            addCriterion("bsaralry <", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryLessThanOrEqualTo(Double value) {
            addCriterion("bsaralry <=", value, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryIn(List<Double> values) {
            addCriterion("bsaralry in", values, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryNotIn(List<Double> values) {
            addCriterion("bsaralry not in", values, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryBetween(Double value1, Double value2) {
            addCriterion("bsaralry between", value1, value2, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andBsaralryNotBetween(Double value1, Double value2) {
            addCriterion("bsaralry not between", value1, value2, "bsaralry");
            return (Criteria) this;
        }

        public Criteria andHiredateIsNull() {
            addCriterion("hiredate is null");
            return (Criteria) this;
        }

        public Criteria andHiredateIsNotNull() {
            addCriterion("hiredate is not null");
            return (Criteria) this;
        }

        public Criteria andHiredateEqualTo(Date value) {
            addCriterionForJDBCDate("hiredate =", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateNotEqualTo(Date value) {
            addCriterionForJDBCDate("hiredate <>", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateGreaterThan(Date value) {
            addCriterionForJDBCDate("hiredate >", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateGreaterThanOrEqualTo(Date value) {
            addCriterionForJDBCDate("hiredate >=", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateLessThan(Date value) {
            addCriterionForJDBCDate("hiredate <", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateLessThanOrEqualTo(Date value) {
            addCriterionForJDBCDate("hiredate <=", value, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateIn(List<Date> values) {
            addCriterionForJDBCDate("hiredate in", values, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateNotIn(List<Date> values) {
            addCriterionForJDBCDate("hiredate not in", values, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateBetween(Date value1, Date value2) {
            addCriterionForJDBCDate("hiredate between", value1, value2, "hiredate");
            return (Criteria) this;
        }

        public Criteria andHiredateNotBetween(Date value1, Date value2) {
            addCriterionForJDBCDate("hiredate not between", value1, value2, "hiredate");
            return (Criteria) this;
        }

        public Criteria andAddressIsNull() {
            addCriterion("address is null");
            return (Criteria) this;
        }

        public Criteria andAddressIsNotNull() {
            addCriterion("address is not null");
            return (Criteria) this;
        }

        public Criteria andAddressEqualTo(String value) {
            addCriterion("address =", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressNotEqualTo(String value) {
            addCriterion("address <>", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressGreaterThan(String value) {
            addCriterion("address >", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressGreaterThanOrEqualTo(String value) {
            addCriterion("address >=", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressLessThan(String value) {
            addCriterion("address <", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressLessThanOrEqualTo(String value) {
            addCriterion("address <=", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressLike(String value) {
            addCriterion("address like", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressNotLike(String value) {
            addCriterion("address not like", value, "address");
            return (Criteria) this;
        }

        public Criteria andAddressIn(List<String> values) {
            addCriterion("address in", values, "address");
            return (Criteria) this;
        }

        public Criteria andAddressNotIn(List<String> values) {
            addCriterion("address not in", values, "address");
            return (Criteria) this;
        }

        public Criteria andAddressBetween(String value1, String value2) {
            addCriterion("address between", value1, value2, "address");
            return (Criteria) this;
        }

        public Criteria andAddressNotBetween(String value1, String value2) {
            addCriterion("address not between", value1, value2, "address");
            return (Criteria) this;
        }

        public Criteria andDepidIsNull() {
            addCriterion("depid is null");
            return (Criteria) this;
        }

        public Criteria andDepidIsNotNull() {
            addCriterion("depid is not null");
            return (Criteria) this;
        }

        public Criteria andDepidEqualTo(Integer value) {
            addCriterion("depid =", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotEqualTo(Integer value) {
            addCriterion("depid <>", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidGreaterThan(Integer value) {
            addCriterion("depid >", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidGreaterThanOrEqualTo(Integer value) {
            addCriterion("depid >=", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidLessThan(Integer value) {
            addCriterion("depid <", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidLessThanOrEqualTo(Integer value) {
            addCriterion("depid <=", value, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidIn(List<Integer> values) {
            addCriterion("depid in", values, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotIn(List<Integer> values) {
            addCriterion("depid not in", values, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidBetween(Integer value1, Integer value2) {
            addCriterion("depid between", value1, value2, "depid");
            return (Criteria) this;
        }

        public Criteria andDepidNotBetween(Integer value1, Integer value2) {
            addCriterion("depid not between", value1, value2, "depid");
            return (Criteria) this;
        }
    }

    public static class Criteria extends GeneratedCriteria {

        protected Criteria() {
            super();
        }
    }

    public static class Criterion {
        private String condition;

        private Object value;

        private Object secondValue;

        private boolean noValue;

        private boolean singleValue;

        private boolean betweenValue;

        private boolean listValue;

        private String typeHandler;

        public String getCondition() {
            return condition;
        }

        public Object getValue() {
            return value;
        }

        public Object getSecondValue() {
            return secondValue;
        }

        public boolean isNoValue() {
            return noValue;
        }

        public boolean isSingleValue() {
            return singleValue;
        }

        public boolean isBetweenValue() {
            return betweenValue;
        }

        public boolean isListValue() {
            return listValue;
        }

        public String getTypeHandler() {
            return typeHandler;
        }

        protected Criterion(String condition) {
            super();
            this.condition = condition;
            this.typeHandler = null;
            this.noValue = true;
        }

        protected Criterion(String condition, Object value, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.typeHandler = typeHandler;
            if (value instanceof List<?>) {
                this.listValue = true;
            } else {
                this.singleValue = true;
            }
        }

        protected Criterion(String condition, Object value) {
            this(condition, value, null);
        }

        protected Criterion(String condition, Object value, Object secondValue, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.secondValue = secondValue;
            this.typeHandler = typeHandler;
            this.betweenValue = true;
        }

        protected Criterion(String condition, Object value, Object secondValue) {
            this(condition, value, secondValue, null);
        }
    }
}

mapper.java

import com.demo.entity.Depart;
import com.demo.entity.DepartExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface DepartMapper {
    int countByExample(DepartExample example);

    int deleteByExample(DepartExample example);

    int deleteByPrimaryKey(Integer depid);

    int insert(Depart record);

    int insertSelective(Depart record);

    List<Depart> selectByExample(DepartExample example);

    Depart selectByPrimaryKey(Integer depid);

    int updateByExampleSelective(@Param("record") Depart record, @Param("example") DepartExample example);

    int updateByExample(@Param("record") Depart record, @Param("example") DepartExample example);

    int updateByPrimaryKeySelective(Depart record);

    int updateByPrimaryKey(Depart record);
}


import com.demo.entity.Employee;
import com.demo.entity.EmployeeExample;

import java.util.List;

import org.apache.ibatis.annotations.Param;

public interface EmployeeMapper {
    int countByExample(EmployeeExample example);

    //根据条件删除
    int deleteByExample(EmployeeExample example);

    //根据主键删除
    int deleteByPrimaryKey(Integer empid);

    int insert(Employee record);

    //添加的方法
    int insertSelective(Employee record);

    //根据条件查询多条记录，如果参数为null就是查询全部
    List<Employee> selectByExample(EmployeeExample example);

    //根据主键查询单条记录
    Employee selectByPrimaryKey(Integer empid);

    int updateByExampleSelective(@Param("record") Employee record, @Param("example") EmployeeExample example);

    int updateByExample(@Param("record") Employee record, @Param("example") EmployeeExample example);

    //修改记录
    int updateByPrimaryKeySelective(Employee record);

    int updateByPrimaryKey(Employee record);
}

mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.demo.mapper.DepartMapper" >
  <resultMap id="BaseResultMap" type="com.demo.entity.Depart" >
    <id column="depid" property="depid" jdbcType="INTEGER" />
    <result column="depname" property="depname" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Example_Where_Clause" >
    <where >
      <foreach collection="oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause" >
    <where >
      <foreach collection="example.oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List" >
    depid, depname
  </sql>
  <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.demo.entity.DepartExample" >
    select
    <if test="distinct" >
      distinct
    </if>
    <include refid="Base_Column_List" />
    from depart
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from depart
    where depid = #{depid,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from depart
    where depid = #{depid,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="com.demo.entity.DepartExample" >
    delete from depart
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="com.demo.entity.Depart" >
    insert into depart (depid, depname)
    values (#{depid,jdbcType=INTEGER}, #{depname,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.demo.entity.Depart" >
    insert into depart
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="depid != null" >
        depid,
      </if>
      <if test="depname != null" >
        depname,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="depid != null" >
        #{depid,jdbcType=INTEGER},
      </if>
      <if test="depname != null" >
        #{depname,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.demo.entity.DepartExample" resultType="java.lang.Integer" >
    select count(*) from depart
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map" >
    update depart
    <set >
      <if test="record.depid != null" >
        depid = #{record.depid,jdbcType=INTEGER},
      </if>
      <if test="record.depname != null" >
        depname = #{record.depname,jdbcType=VARCHAR},
      </if>
    </set>
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map" >
    update depart
    set depid = #{record.depid,jdbcType=INTEGER},
      depname = #{record.depname,jdbcType=VARCHAR}
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="com.demo.entity.Depart" >
    update depart
    <set >
      <if test="depname != null" >
        depname = #{depname,jdbcType=VARCHAR},
      </if>
    </set>
    where depid = #{depid,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.demo.entity.Depart" >
    update depart
    set depname = #{depname,jdbcType=VARCHAR}
    where depid = #{depid,jdbcType=INTEGER}
  </update>
</mapper>


<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.demo.mapper.EmployeeMapper" >
  <resultMap id="BaseResultMap" type="com.demo.entity.Employee" >
    <id column="empid" property="empid" jdbcType="INTEGER" />
    <result column="empname" property="empname" jdbcType="VARCHAR" />
    <result column="bsaralry" property="bsaralry" jdbcType="DOUBLE" />
    <result column="hiredate" property="hiredate" jdbcType="DATE" />
    <result column="address" property="address" jdbcType="VARCHAR" />
    <result column="depid" property="depid" jdbcType="INTEGER" />
  </resultMap>
  <sql id="Example_Where_Clause" >
    <where >
      <foreach collection="oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause" >
    <where >
      <foreach collection="example.oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List" >
    empid, empname, bsaralry, hiredate, address, depid
  </sql>
  <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.demo.entity.EmployeeExample" >
    select
    <if test="distinct" >
      distinct
    </if>
    <include refid="Base_Column_List" />
    from employee
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from employee
    where empid = #{empid,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from employee
    where empid = #{empid,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="com.demo.entity.EmployeeExample" >
    delete from employee
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="com.demo.entity.Employee" >
    insert into employee (empid, empname, bsaralry, 
      hiredate, address, depid
      )
    values (#{empid,jdbcType=INTEGER}, #{empname,jdbcType=VARCHAR}, #{bsaralry,jdbcType=DOUBLE}, 
      #{hiredate,jdbcType=DATE}, #{address,jdbcType=VARCHAR}, #{depid,jdbcType=INTEGER}
      )
  </insert>
  <insert id="insertSelective" parameterType="com.demo.entity.Employee" >
    insert into employee
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="empid != null" >
        empid,
      </if>
      <if test="empname != null" >
        empname,
      </if>
      <if test="bsaralry != null" >
        bsaralry,
      </if>
      <if test="hiredate != null" >
        hiredate,
      </if>
      <if test="address != null" >
        address,
      </if>
      <if test="depid != null" >
        depid,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="empid != null" >
        #{empid,jdbcType=INTEGER},
      </if>
      <if test="empname != null" >
        #{empname,jdbcType=VARCHAR},
      </if>
      <if test="bsaralry != null" >
        #{bsaralry,jdbcType=DOUBLE},
      </if>
      <if test="hiredate != null" >
        #{hiredate,jdbcType=DATE},
      </if>
      <if test="address != null" >
        #{address,jdbcType=VARCHAR},
      </if>
      <if test="depid != null" >
        #{depid,jdbcType=INTEGER},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.demo.entity.EmployeeExample" resultType="java.lang.Integer" >
    select count(*) from employee
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map" >
    update employee
    <set >
      <if test="record.empid != null" >
        empid = #{record.empid,jdbcType=INTEGER},
      </if>
      <if test="record.empname != null" >
        empname = #{record.empname,jdbcType=VARCHAR},
      </if>
      <if test="record.bsaralry != null" >
        bsaralry = #{record.bsaralry,jdbcType=DOUBLE},
      </if>
      <if test="record.hiredate != null" >
        hiredate = #{record.hiredate,jdbcType=DATE},
      </if>
      <if test="record.address != null" >
        address = #{record.address,jdbcType=VARCHAR},
      </if>
      <if test="record.depid != null" >
        depid = #{record.depid,jdbcType=INTEGER},
      </if>
    </set>
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map" >
    update employee
    set empid = #{record.empid,jdbcType=INTEGER},
      empname = #{record.empname,jdbcType=VARCHAR},
      bsaralry = #{record.bsaralry,jdbcType=DOUBLE},
      hiredate = #{record.hiredate,jdbcType=DATE},
      address = #{record.address,jdbcType=VARCHAR},
      depid = #{record.depid,jdbcType=INTEGER}
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="com.demo.entity.Employee" >
    update employee
    <set >
      <if test="empname != null" >
        empname = #{empname,jdbcType=VARCHAR},
      </if>
      <if test="bsaralry != null" >
        bsaralry = #{bsaralry,jdbcType=DOUBLE},
      </if>
      <if test="hiredate != null" >
        hiredate = #{hiredate,jdbcType=DATE},
      </if>
      <if test="address != null" >
        address = #{address,jdbcType=VARCHAR},
      </if>
      <if test="depid != null" >
        depid = #{depid,jdbcType=INTEGER},
      </if>
    </set>
    where empid = #{empid,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.demo.entity.Employee" >
    update employee
    set empname = #{empname,jdbcType=VARCHAR},
      bsaralry = #{bsaralry,jdbcType=DOUBLE},
      hiredate = #{hiredate,jdbcType=DATE},
      address = #{address,jdbcType=VARCHAR},
      depid = #{depid,jdbcType=INTEGER}
    where empid = #{empid,jdbcType=INTEGER}
  </update>
</mapper>

service

import com.demo.entity.Employee;

import java.util.List;

public interface EmployeeService {
    List<Employee> getEmpList();

}

import com.demo.entity.Employee;
import com.demo.mapper.EmployeeMapper;
import com.demo.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service//告诉框架这是一个业务类
@Transactional//开启事务处理
public class EmployeeServiceImpl implements EmployeeService {
    @Autowired//该注解会自动配置一个employeeMapper对象，相当于new一个对象
    private EmployeeMapper employeeMapper;

    @Override
    public List<Employee> getEmpList() {
        return employeeMapper.selectByExample(null);
    }

}

controller

package com.demo.controller;

import com.demo.entity.Employee;
import com.demo.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.apache.log4j.Logger;

import java.util.List;
import java.util.Map;

@Controller//告诉框架这是控制器
public class EmployeeController {
    @Autowired//自动分配对象，
    private EmployeeService employeeService;
    // 创建Logger实例
    private static final Logger logger = Logger.getLogger(EmployeeController.class);

    /**
     * 原来再servlet中会配置servlet-maping url,现在是通过
     *
     * @RequestMapping来声明请求的url的 http://localhost:8080/list
     */
    @RequestMapping(name = "/list")
    public String getEmpList(Map map) {
        // 添加日志记录方法开始
        logger.info("开始获取员工列表");
        List<Employee> empList = employeeService.getEmpList();
        //原来我们在servlet中可以把数据储存再request和session中，现在存在map中相当于存储到request作用域中。
        map.put("empList", empList);

        // 添加日志记录获取到的员工数量
        logger.info("成功获取员工列表，共 " + empList.size() + " 条记录");

        /**
         * return "list"中的list称为视图的逻辑名，我们的目的是要找到物理视图名
         * list.jsp是物理视图名
         *  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         *         <property name="prefix" value="/WEB-INF/jsp/"/>
         *         <property name="suffix" value=".jsp"/>
         *   </bean>
         *
         *   匹配方式：前缀+逻辑名+后缀
         *   /WEB-INF/jsp/list.jsp
         *http://localhost:8080/index.jsp
         */
        return "list";
    }

}