开始尝试从0写一个项目--后端（二）

实现学生管理

新增学生

接口设计

请求路径：/admin/student

请求方法：POST

请求参数：请求头：Headers："Content-Type": "application/json"

请求体：Body：

id 学生id

idNumber 学生身份证

name 名字

phone 电话号码

sex 性别

username 用户名

返回数据：Result

student表设计

代码开发

设计DTO类接收前端传来的参数

sems-pojo/src/main/java/com/ljc/dto/StudentDTO.java

package com.ljc.dto;

import lombok.Data;

import java.io.Serializable;

@Data
public class StudentDTO implements Serializable {

    //学生id
    private Long id;

    //用户名
    private String username;

    //姓名
    private String name;

    //电话
    private String phone;

    //性别
    private String sex;

    //身份证号
    private String idNumber;

}

controller层

sems-server/src/main/java/com/ljc/controller/student/StudentController.java

package com.ljc.controller.student;

import com.ljc.constant.JwtClaimsConstant;
import com.ljc.dto.StudentDTO;
import com.ljc.dto.StudentLoginDTO;
import com.ljc.entity.Student;
import com.ljc.properties.JwtProperties;
import com.ljc.result.Result;
import com.ljc.service.StudentService;
import com.ljc.utils.JwtUtil;
import com.ljc.vo.StudentLoginVO;

import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/admin/student")
@Slf4j
public class StudentController {
    @Autowired
    private StudentService studentService;
    @Autowired
    private JwtProperties jwtProperties;

    /**
     * 登录
     *
     * @param studentLoginDTO
     * @return
     */
    @ApiOperation("用户登录")
    @PostMapping("/login")
    public Result<StudentLoginVO> login(@RequestBody StudentLoginDTO studentLoginDTO) {
        log.info("学生登录：{}", studentLoginDTO);

        Student student = studentService.login(studentLoginDTO);

        //登录成功后，生成jwt令牌
        Map<String, Object> claims = new HashMap<>();
        claims.put(JwtClaimsConstant.EMP_ID, student.getId());
        String token = JwtUtil.createJWT(
                jwtProperties.getAdminSecretKey(),
                jwtProperties.getAdminTtl(),
                claims);

        StudentLoginVO studentLoginVO = StudentLoginVO.builder()
                .id(student.getId())
                .userName(student.getUsername())
                .name(student.getName())
                .token(token)
                .build();

        return Result.success(studentLoginVO);
    }

    /**
     * 退出
     *
     * @return
     */
    @ApiOperation("用户退出")
    @PostMapping("/logout")
    public Result<String> logout() {
        return Result.success();
    }


    /**
     * 新增学生
     * @param studentDTO
     * @return
     */
    @PostMapping
    @ApiOperation("新增学生")
    public Result save(@RequestBody StudentDTO studentDTO){
        //日志，现在进行的是新增学生功能
        log.info("新增学生：{}", studentDTO);

        //调用service层（处理层）的方法进行新增
        studentService.save(studentDTO);

        return Result.success();
    }

}

Service层

sems-server/src/main/java/com/ljc/service/StudentService.java

package com.ljc.service;

import com.ljc.dto.StudentDTO;
import com.ljc.dto.StudentLoginDTO;
import com.ljc.entity.Student;

public interface StudentService {

    /**
     * 学生登录
     * @param studentLoginDTO
     * @return
     */
    Student login(StudentLoginDTO studentLoginDTO);

    /**
     * 新增学生
     * @param studentDTO
     */
    void save(StudentDTO studentDTO);
}

ServiceImpl层

sems-server/src/main/java/com/ljc/service/impl/StudentServiceImpl.java

package com.ljc.service.impl;

import com.ljc.constant.MessageConstant;
import com.ljc.constant.PasswordConstant;
import com.ljc.constant.StatusConstant;
import com.ljc.context.BaseContext;
import com.ljc.dto.StudentDTO;
import com.ljc.dto.StudentLoginDTO;
import com.ljc.entity.Student;
import com.ljc.exception.AccountLockedException;
import com.ljc.exception.AccountNotFoundException;
import com.ljc.exception.PasswordErrorException;
import com.ljc.mapper.StudentMapper;
import com.ljc.service.StudentService;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.DigestUtils;

import java.time.LocalDateTime;

@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    /**
     * 学生登录
     *
     * @param studentLoginDTO
     * @return
     */
    public Student login(StudentLoginDTO studentLoginDTO) {
        String username = studentLoginDTO.getUsername();
        String password = studentLoginDTO.getPassword();

        //1、根据用户名查询数据库中的数据
        Student student = studentMapper.getByUsername(username);

        //2、处理各种异常情况（用户名不存在、密码不对、账号被锁定）
        if (student == null) {
            //账号不存在
            throw new AccountNotFoundException(MessageConstant.ACCOUNT_NOT_FOUND);
        }

        //密码比对
        // 进行md5加密，然后再进行比对
        password = DigestUtils.md5DigestAsHex(password.getBytes());
        if (!password.equals(student.getPassword())) {
            //密码错误
            throw new PasswordErrorException(MessageConstant.PASSWORD_ERROR);
        }

        if (student.getStatus() == StatusConstant.DISABLE) {
            //账号被锁定
            throw new AccountLockedException(MessageConstant.ACCOUNT_LOCKED);
        }

        //3、返回实体对象
        return student;
    }


    /**
     *
     * 新增学生
     * @param studentDTO
     */
    @Override
    public void save(StudentDTO studentDTO) {
        //1. 创建一个学生对象
        Student student = new Student();

        //2. 将前端传后来的参数，即就是封装在DTO里面的数据转移到学生对象中
        //调用对象属性拷贝，括号里面参数，前面的是需要传递的数据，后面的是接收的数据
        BeanUtils.copyProperties(studentDTO,student);

        //3. 补充student里面的数据，前端没有传递回来的

        //3.1 前端没有传递账号状态，现在给设置账号状态:默认为正常，正常为1，异常为0；
        //由于1太不美观了，创建一个常量类
        /*student.setStatus(1);*/
        student.setStatus(StatusConstant.ENABLE);

        //3.2 设置密码:默认为123456，进行MD5加密
        //密码也设置一个常量：PasswordConstant.DEFAULT_PASSWORD
        /*student.setPassword(DigestUtils.md5DigestAsHex("123456".getBytes()));*/
        student.setPassword(DigestUtils.md5DigestAsHex(PasswordConstant.DEFAULT_PASSWORD.getBytes()));

        //3.3 设置创建时间和修改时间: 为当前时间
        student.setCreateTime(LocalDateTime.now());
        student.setUpdateTime(LocalDateTime.now());

        //3.4 设置创建人的id
        student.setCreateUser(BaseContext.getCurrentId());
        student.setUpdateUser(BaseContext.getCurrentId());

        //4 调用mapper层数据，连接数据库，对数据库进行操作
        studentMapper.insert(student);

    }

}

mapper层

sems-server/src/main/java/com/ljc/mapper/StudentMapper.java

package com.ljc.mapper;

import com.ljc.entity.Student;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

@Mapper
public interface StudentMapper {

    /**
     * 根据用户名查询学生
     * @param username
     * @return
     */
    @Select("select * from student where username = #{username}")
    Student getByUsername(String username);

    /**
     * 新增学生
     * @param student
     */
    @Insert("insert into student (name, username, password, phone, sex, id_number, create_time, update_time, create_user, update_user,status) " +
            "values " +
            "(#{name},#{username},#{password},#{phone},#{sex},#{idNumber},#{createTime},#{updateTime},#{createUser},#{updateUser},#{status})")
    void insert(Student student);
}

补充代码

这里面有几个常量值，和一个ThreadLocal来获取jwt令牌里面的用户名

封装了 ThreadLocal 操作的工具类：

sems-common/src/main/java/com/ljc/context/BaseContext.java

package com.ljc.context;

public class BaseContext {

    public static ThreadLocal<Long> threadLocal = new ThreadLocal<>();

    public static void setCurrentId(Long id) {
        threadLocal.set(id);
    }

    public static Long getCurrentId() {
        return threadLocal.get();
    }

    public static void removeCurrentId() {
        threadLocal.remove();
    }

}

常量类

密码

sems-common/src/main/java/com/ljc/constant/PasswordConstant.java

package com.ljc.constant;

/**
 * 密码常量
 */
public class PasswordConstant {

    public static final String DEFAULT_PASSWORD = "123456";

}

补充用户名重复常量

sems-common/src/main/java/com/ljc/constant/MessageConstant.java

package com.ljc.constant;

/**
 * 信息提示常量类
 */
public class MessageConstant {

    public static final String PASSWORD_ERROR = "密码错误";
    public static final String ACCOUNT_NOT_FOUND = "账号不存在";
    public static final String ACCOUNT_LOCKED = "账号被锁定";
    public static final String UNKNOWN_ERROR = "未知错误";
    public static final String USER_NOT_LOGIN = "用户未登录";
    public static final String CATEGORY_BE_RELATED_BY_SETMEAL = "当前分类关联了套餐,不能删除";
    public static final String CATEGORY_BE_RELATED_BY_DISH = "当前分类关联了菜品,不能删除";
    public static final String SHOPPING_CART_IS_NULL = "购物车数据为空，不能下单";
    public static final String ADDRESS_BOOK_IS_NULL = "用户地址为空，不能下单";
    public static final String LOGIN_FAILED = "登录失败";
    public static final String UPLOAD_FAILED = "文件上传失败";
    public static final String SETMEAL_ENABLE_FAILED = "套餐内包含未启售菜品，无法启售";
    public static final String PASSWORD_EDIT_FAILED = "密码修改失败";
    public static final String DISH_ON_SALE = "起售中的菜品不能删除";
    public static final String SETMEAL_ON_SALE = "起售中的套餐不能删除";
    public static final String DISH_BE_RELATED_BY_SETMEAL = "当前菜品关联了套餐,不能删除";
    public static final String ORDER_STATUS_ERROR = "订单状态错误";
    public static final String ORDER_NOT_FOUND = "订单不存在";

    public static final String ALREADY_EXISTS = "已存在";
}

处理用户名重复的异常

sems-server/src/main/java/com/ljc/handler/GlobalExceptionHandler.java

package com.ljc.handler;

import com.ljc.constant.MessageConstant;
import com.ljc.exception.BaseException;
import com.ljc.result.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.sql.SQLIntegrityConstraintViolationException;

/**
 * 全局异常处理器，处理项目中抛出的业务异常
 */
@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {

    /**
     * 捕获业务异常
     * @param ex
     * @return
     */
    @ExceptionHandler
    public Result exceptionHandler(BaseException ex){
        log.error("异常信息：{}", ex.getMessage());
        return Result.error(ex.getMessage());
    }

    /**
     * 捕获用户名重复
     * */
    @ExceptionHandler
    public Result exceptionHandler(SQLIntegrityConstraintViolationException ex){
        //Duplicate entry 'zhangsan' for key 'employee.idx_username'
        //获取异常信息
        String massage = ex.getMessage();

        //以” “分割异常信息；
        if (massage.contains("Duplicate entry")){
            String[] split = massage.split(" ");
            String name = split[2];
            String msg = name+ MessageConstant.ALREADY_EXISTS;//已存在已有常量，尽量避免字符串
            return Result.error(msg);
        }else {
            return Result.error(MessageConstant.UNKNOWN_ERROR);
        }


    }

}

测试

完成后进入swagger界面测试一下

因为需要进行jwt令牌检测，所以

使用admin用户登录获取令牌

将合法的JWT令牌添加到全局参数中

检查一下添加上了没

然后开始测试

检查数据库添加上了没

学生分页查询

开发到这里我发现还得先开发前端，前端明确后，后端才有针对性，所以先完成前端代码。

麻了，前端一点不会啊，工期有点长了.....................