Java 繁琐写法

@Data
public class People {
    private String name;
    private Integer age;
    private String sex;
    private String address;
    private String phoneNo;

    public static class PeopleBuilder {
        // 必选参数
        private String name;
        private Integer age;
        // 可选参数
        private String sex;
        private String address;
        private String phoneNo;

        public PeopleBuilder(String name, Integer age) {
            this.name = name;
            this.age = age;
        }

        public PeopleBuilder sex(String sex) {
            this.sex = sex;
            return this;
        }

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

        public PeopleBuilder phoneNo(String phoneNo) {
            this.phoneNo = phoneNo;
            return this;
        }

        public People build() {
            return new People(this);
        }
    }

    private People(PeopleBuilder peopleBuilder) {
        this.name = peopleBuilder.name;
        this.age = peopleBuilder.age;
        this.address = peopleBuilder.address;
        this.sex = peopleBuilder.sex;
        this.phoneNo = peopleBuilder.phoneNo;
    }

    public static void main(String[] args) {
        People people = new PeopleBuilder("Jone", 30).address("hz").build();
        System.out.println(people.getName());
    }
}

lombok 之 @Builder

@Builder
@Data
public class People {
    private String name;
    private Integer age;
    private String sex;
    private String address;
    private String phoneNo;
    public static void main(String[] args) {
        People people = People.builder().address("hz").phoneNo("123").build();
        System.out.println(people.getPhoneNo());
    }
}

• 重叠构造器模式
  特点：若干个构造方法，最短的一个参数，最长的包含所有参数
  缺点：显而易见，难以阅读
• JavaBeans模式
  特点：一个无参数的构造函数加各种setter 方法。
  缺点：构造方法在多次调用中被分割，所以在构造过程中JavaBean可能处于不一致的状态
• builder 模式
  Builder模式既能保证像重叠构造器模式那样的安全性，也能保证像JavaBeans模式那么好的可读性。Builder模式不直接生成想要的对象，而是让客户端利用所有必要的参数调用构造器（或者静态工厂），得到一个builder对象。然后客户端在builder对象上调用类似于setter的方法，来设置每个相关的可选参数。最后，客户端调用无参的builder方法来生成不可变的对象。