Java Builder模式的写法和lombok插件@Builder注解的支持

1. Builder模式简化get set方法，只需要定义一个静态公共的内部类即可

public class User {
    private Integer id;
    private String name;
    private String address;

    private User() {
    }

    private User(User origin) {
        this.id = origin.id;
        this.name = origin.name;
        this.address = origin.address;
    }

    public static class Builder {
        private User target;

        public Builder() {
            this.target = new User();
        }

        public Builder id(Integer id) {
            target.id = id;
            return this;
        }

        public Builder name(String name) {
            target.name = name;
            return this;
        }

        public Builder address(String address) {
            target.address = address;
            return this;
        }

        public User build() {
            return new User(target);
        }
    }



public class User {
    private Integer id;
    private String name;
    private String address;

    private User() {
    }

    private User(User origin) {
        this.id = origin.id;
        this.name = origin.name;
        this.address = origin.address;
    }

    public static class Builder {
        private User target;

        public Builder() {
            this.target = new User();
        }

        public Builder id(Integer id) {
            target.id = id;
            return this;
        }

        public Builder name(String name) {
            target.name = name;
            return this;
        }

        public Builder address(String address) {
            target.address = address;
            return this;
        }

        public User build() {
            return new User(target);
        }
    }

2.如果项目中有使用lombok的话，可以直接使用@Builder注解来实现

定义工具类如下：

import lombok.Builder;
import lombok.ToString;

/**
 * @author wulongtao
 */
@ToString
@Builder
public class UserExample {
    private Integer id;
    private String name;
    private String address;
}


import lombok.Builder;
import lombok.ToString;

/**
 * @author wulongtao
 */
@ToString
@Builder
public class UserExample {
    private Integer id;
    private String name;
    private String address;
}

使用方法：

UserExample userExample = UserExample.builder()
                .id(1)
                .name("aaa")
                .address("bbb")
                .build();

System.out.println(userExample);

UserExample userExample = UserExample.builder()
                .id(1)
                .name("aaa")
                .address("bbb")
                .build();

System.out.println(userExample);