小架构step系列17：getter-setter-toString

1 概述

在写代码的时候，有两类bean：一类是专门承载数据而无业务逻辑的bean，如DTO；另外一类是业务模型bean，其既要承载数据也要提供业务逻辑，在DDD中它们就对应于领域模型对象和值对象。这些bean里面可能要提供getter、setter、equals、hashCode、toString，甚至构造方法，这些代码写起来比较无聊，基本都是根据字段来的，属于非常机械化而无技术含量的操作，而这些操作还相当多，增加一个字段或者改一个字段也得响应地进行调整，耗时耗力的。即使定义相关规范，强制要写这些方法，也很容易遗忘掉。遗忘掉toString()方法还会导致打印到日志里的对象没有详细信息，对定位问题毫无帮助。

为了解决这个问题，像IDEA这类IDE，都提供了生成方法的手段，帮助快速生成。但更快的方法就是连生成都不需要，只有个注解就解决问题，这正是Lombok提供的方法。

2 Lombok的使用

2.1 引入依赖

在pom.xml中引入lombok包的依赖：

<properties>
    <lombok.version>1.18.30</lombok.version>
</properties>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${lombok.version}</version>
    <scope>provided</scope>
</dependency>

2.2 使用Lombok的注解

加上注解@Data

import lombok.Data;

@Data
public class Member {
    private Long groupId;
    private String name;
    private Integer age;
    private GroupMemberGender gender;
}

Lombok会帮助生成：

public class Member {
    private Long groupId;
    private String name;
    private Integer age;
    private GroupMemberGender gender;

    // 生成getter/setter
    public Long getGroupId() {
        return this.groupId;
    }
    public void setGroupId(Long groupId) {
        this.groupId = groupId;
    }
    public String getName() {
        return this.name;
    }
    public Integer getAge() {
        return this.age;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public GroupMemberGender getGender() {
        return this.gender;
    }
    public void setGender(GroupMemberGender gender) {
        this.gender = gender;
    }

    // 生成equals()方法
    public boolean equals(Object o) {
        if (o == this) return true;
        if (!(o instanceof Member)) return false;
        Member other = (Member) o;
        if (!other.canEqual(this)) return false;
        Object this$groupId = getGroupId(), other$groupId = other.getGroupId();
        if ((this$groupId == null) ? (other$groupId != null) : !this$groupId.equals(other$groupId)) return false;
        Object this$name = getName(), other$name = other.getName();
        if ((this$name == null) ? (other$name != null) : !this$name.equals(other$name)) return false;
        Object this$age = getAge(), other$age = other.getAge();
        if ((this$age == null) ? (other$age != null) : !this$age.equals(other$age)) return false;
        Object this$gender = getGender(), other$gender = other.getGender();
        return !((this$gender == null) ? (other$gender != null) : !this$gender.equals(other$gender));
    }

    protected boolean canEqual(Object other) {
        return other instanceof Member;
    }

    // 生成hashCode()方法
    public int hashCode() {
        int PRIME = 59;
        result = 1;
        Object $groupId = getGroupId();
        result = result * 59 + (($groupId == null) ? 43 : $groupId.hashCode());
        Object $name = getName();
        result = result * 59 + (($name == null) ? 43 : $name.hashCode());
        Object $age = getAge();
        result = result * 59 + (($age == null) ? 43 : $age.hashCode());
        Object $gender = getGender();
        return result * 59 + (($gender == null) ? 43 : $gender.hashCode());
    }

    // 生成toString()方法
    public String toString() {
        return "Member(groupId=" + getGroupId() + ", name=" + getName() + ", age=" + getAge() + ", gender=" + getGender() + ")";
    }
}

@Getter and @Setter
@FieldNameConstants
@ToString
@EqualsAndHashCode
@AllArgsConstructor
@RequiredArgsConstructor
@NoArgsConstructor
@Log
@Log4j
@Log4j2
@Slf4j
@XSlf4j
@CommonsLog
@JBossLog
@Flogger
@CustomLog
@Data
@Builder
@SuperBuilder
@Singular
@Delegate
@Value
@Accessors
@Wither
@With
@SneakyThrows
@StandardException
@val
@var
@UtilityClass

java: You aren't using a compiler supported by lombok, so lombok will not work and has been disabled.
  Your processor is: com.sun.proxy.$Proxy25
  Lombok supports: sun/apple javac 1.6, ECJ

<!-- pom.xml中用的是spring-boot-maven-plugin插件：-->
<build>
    <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
    </plugin>
</build>

<!-- spring-boot-maven-plugin插件依赖plexus-build-api包：-->
<dependency>
  <groupId>org.sonatype.plexus</groupId>
  <artifactId>plexus-build-api</artifactId>
  <version>0.0.7</version>
  <scope>runtime</scope>
</dependency>

<!-- plexus-build-api包依赖maven-compiler-plugin插件包：-->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
      <source>1.4</source>
      <target>1.4</target>
    </configuration>
</plugin>

# lombok-1.18.30.jar!/META-INF/services/javax.annotation.processing.Processor
lombok.launch.AnnotationProcessorHider$AnnotationProcessor
lombok.launch.AnnotationProcessorHider$ClaimingProcessor