Lombok使用4（鏈式調用）

本篇文章會講到：@Accessors、@Buinder 註解使用。

 

1、@Accessors使用

• @Accessors官方文檔地址
• 注註解在屬性（類）上，配置getter和setter方法的生成結果，分別有三個屬性：fluent、chain、prefix。
• fluent的中文含義是流暢的，設置爲true，則getter和setter方法的方法名都是基礎屬性名，且setter方法返回當前對象。
• chain的中文含義是鏈式的，設置爲true，則setter方法返回當前對象。
• prefix的中文含義是前綴，用於生成getter和setter方法的字段名會忽視指定前綴（遵守駝峯命名）。

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

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

    private String name;

    private String phone;

    private int age;

}

編譯後：

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;
    }
}

 驗證結果：

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

 

2、@Buinder使用

• @Buinder官方文檔地址
• builder 是現在比較推崇的一種構建值對象的方式。該描述符用於將類改造成 builder（建造者）模式，用在類、方法或者構造函數上。

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<String> occupations;
}

 編譯後：

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 + ")";
    }
  }
}

驗證結果：

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

 

更多閱讀

•  Lombok基礎使用介紹
• Lombok使用2（常用註解）
• Lombok使用3（其他註解）
• Lombok使用4（鏈式調用）