builder方法来构造对象

利用Builder来构建对象

优势：通常构造对象的方法有两种。一、全参数构造方法；二、无参构造函数，然后通过get和set方法。

第一种很多参数不需要设置，而且可能弄混；

第二种每一个值都要set一次，设置起来很累。

然后就有Builder对象链式编程来简化构造对象，原理就是返回this对象，就是返回本身，来达到链式编程的目的。

如下图，Refactor自动生成builder方法

@Data
public class BasicStudent {
    private int id;
    private String name;
    private String sex;
    private Integer age;

    BasicStudent(int id, String name, String sex, Integer age) {
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public static BasicStudentBuilder builder() {
        return new BasicStudentBuilder();
    }

    public static class BasicStudentBuilder {
        private int id;
        private String name;
        private String sex;
        private Integer age;

        BasicStudentBuilder() {
        }

        public BasicStudentBuilder id(int id) {
            this.id = id;
            return this;
        }

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

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

        public BasicStudentBuilder age(Integer age) {
            this.age = age;
            return this;
        }

        public BasicStudent build() {
            return new BasicStudent(id, name, sex, age);
        }

        @Override
        public String toString() {
            return "BasicStudent.BasicStudentBuilder(id=" + this.id + ", name=" + this.name + ", sex=" + this.sex + ", age=" + this.age + ")";
        }
    }
}

        BasicStudent basicStudent = BasicStudent.builder()
                .id(1)
                .name("yorkiiz")
                .sex("male")
                .build();

如果觉得这样麻烦，可以使用注解来自动生成builder

@Builder
@Data
public class BasicStudent {
    private int id;
    private String name;
    private String sex;
    private Integer age;
    
}

参考链接：https://blog.csdn.net/xsj_blog/article/details/97293751