本篇文章会讲到：@Accessors、@Builder 注解使用。

1、@Accessors使用

• @Accessors官方文档地址

• 注注解在属性（类）上，配置getter和setter方法的生成结果，分别有三个属性：fluent、chain、prefix。

• fluent的中文含义是流畅的，设置为true，则getter和setter方法的方法名都是基础属性名，且setter方法返回当前对象。

• chain的中文含义是链式的，设置为true，则setter方法返回当前对象。

• prefix的中文含义是前缀，用于生成getter和setter方法的字段名会忽视指定前缀（遵守驼峰命名）。

  import lombok.Data; import lombok.experimental.Accessors;

  @Data @Accessors(chain = true) public class Example {

  private String name;
  
  private String phone;
  
  private int age;
  

  }

编译后：

public class Example {

    private String name;

    private String phone;

    private int age;

    public String getName() {
        return name;
    }

    public Example setName(String name) {
        this.name = name;
        return this;
    }

    public String getPhone() {
        return phone;
    }

    public Example setPhone(String phone) {
        this.phone = phone;
        return this;
    }

    public int getAge() {
        return age;
    }

    public Example setAge(int age) {
        this.age = age;
        return this;
    }
}

 验证结果：

Example example = new Example()
        .setName("piao")
        .setAge(24)
        .setPhone("138");

2、@Builder使用

• @Builder官方文档地址

• builder 是现在比较推崇的一种构建值对象的方式。该描述符用于将类改造成 builder（建造者）模式，用在类、方法或者构造函数上。

  import lombok.Builder; import lombok.Singular; import java.util.Set;

  @Builder public class BuilderExample { @Builder.Default private long created = System.currentTimeMillis(); private String name; private int age; @Singular private Set occupations; }

 编译后：

import java.util.Set;

public class BuilderExample {
  private long created;
  private String name;
  private int age;
  private Set<String> occupations;
  
  BuilderExample(String name, int age, Set<String> occupations) {
    this.name = name;
    this.age = age;
    this.occupations = occupations;
  }
  
  private static long $default$created() {
    return System.currentTimeMillis();
  }
  
  public static BuilderExampleBuilder builder() {
    return new BuilderExampleBuilder();
  }
  
  public static class BuilderExampleBuilder {
    private long created;
    private boolean created$set;
    private String name;
    private int age;
    private java.util.ArrayList<String> occupations;
    
    BuilderExampleBuilder() {
    }
    
    public BuilderExampleBuilder created(long created) {
      this.created = created;
      this.created$set = true;
      return this;
    }
    
    public BuilderExampleBuilder name(String name) {
      this.name = name;
      return this;
    }
    
    public BuilderExampleBuilder age(int age) {
      this.age = age;
      return this;
    }
    
    public BuilderExampleBuilder occupation(String occupation) {
      if (this.occupations == null) {
        this.occupations = new java.util.ArrayList<String>();
      }
      
      this.occupations.add(occupation);
      return this;
    }
    
    public BuilderExampleBuilder occupations(Collection<? extends String> occupations) {
      if (this.occupations == null) {
        this.occupations = new java.util.ArrayList<String>();
      }

      this.occupations.addAll(occupations);
      return this;
    }
    
    public BuilderExampleBuilder clearOccupations() {
      if (this.occupations != null) {
        this.occupations.clear();
      }
      
      return this;
    }

    public BuilderExample build() {
      // complicated switch statement to produce a compact properly sized immutable set omitted.
      Set<String> occupations = ...;
      return new BuilderExample(created$set ? created : BuilderExample.$default$created(), name, age, occupations);
    }
    
    @java.lang.Override
    public String toString() {
      return "BuilderExample.BuilderExampleBuilder(created = " + this.created + ", name = " + this.name + ", age = " + this.age + ", occupations = " + this.occupations + ")";
    }
  }
}

验证结果：

BuilderExample example = BuilderExample.builder()
        .name("piao")
        .age(24)
        .occupation("ONE")
        .occupation("TWO")
        .build();

更多阅读

• Lombok使用1：简单介绍
• Lombok使用2：常用注解
• Lombok使用3：其他注解
• Lombok使用4：链式调用