lombok的@Builder的使用，@Builder的使用效果

最新推荐文章于 2025-03-08 00:57:33 发布

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最新推荐文章于 2025-03-08 00:57:33 发布

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文章标签： java 开发语言

本文链接：https://blog.youkuaiyun.com/qq_71751610/article/details/136756768

版权

本文介绍了Java中的@Builder注解，展示了如何通过它简化对象实例化过程，以及其生成的People类和Builder类的结构。通过示例说明了如何在GET请求中使用@Builder创建People对象并打印其ToString结果。

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这篇文章的目的：不介绍@Builder的原理，只说明它的使用效果。

@Builder
@ToString
public class People {
    private Long id;
    private String name;
    private String address;
}

运行后（不要误会这段代码不能直接运行，要自己构建运行环境），查看对应的class文件发现People类变成了：

public class People {
    private Long id;
    private String name;
    private String address;

    People(final Long id, final String name, final String address) {
        this.id = id;
        this.name = name;
        this.address = address;
    }

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

public String toString() {
        return "People(id=" + this.id + ", name=" + this.name + ", address=" + this.address + ")";
    }

    public static class PeopleBuilder {
        private Long id;
        private String name;
        private String address;

        PeopleBuilder() {
        }

        public PeopleBuilder id(final Long id) {
            this.id = id;
            return this;
        }

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

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

        public People build() {
            return new People(this.id, this.name, this.address);
        }

        public String toString() {
            return "People.PeopleBuilder(id=" + this.id + ", name=" + this.name + ", address=" + this.address + ")";
        }
    }
}

所以可以这样使用：

@GetMapping("/hello")
public String hello() {
        //等价与 new People(10L,"lihuo","888")
        People people = People.builder().id(10L).name("lihuo").address("888").build();

        System.out.println(people.toString());

        return "Hello,World";
    }

运行结果：