lombok常用的注解及使用方法

lombok是⼀种简化源码提⾼编程效率的⼯具，⽤于⽣成常⽤的代码。

如何使用lombok

引⼊依赖           

            <dependency>

                <groupId>org.projectlombok</groupId>

                <artifactId>lombok</artifactId>

                <version>${lombok.version}</version>

            </dependency>

安装插件

1、打开IDEA左上角File —> Settings ——>Plugins

常用注解汇总

@val                声明变量时能自行推断变量类型, 并且自带 final 属性,

@Data             @ToString、@EqualsAndHashCode、

                        @Getter、@Setter和 @RequiredArgsConstrutor

@Slf4j             生成 log 对象

@Value            与 @Data 类似, 有以下两点区别:

                        生成的是全参的构造器;

                        只有 getter 方法, 没有 setter 方法;

@Getter           所有属性的Getter方法

@Setter           所有属性的Setter方法

@Builder         生成链式构造器的代码

@Cleanup       安全释放或者关闭资源, 最常见的场景就是 IO 中关闭流的操作

@NonNull

                        getter : 如果获取出来属性为 null, 则抛出 NPE

                        setter : 如果设置属性时, 传入的值为 null, 则抛出 NPE

@ToString        生成 toString() 方法

@SneakyThrows        将抛出的异常吃掉, 减少一些不必要的 try catch 代码

@NoArgsConstructor        生成一个无参构造方法

@AllArgsConstructor        添加一个包含所有属性的Constructor

@EqualsAndHashCode        生成 equals() 和 hashcode() 方法

@RequiredArgsConstrutor        会生成一个包含常量，和标识了NotNull的变量的构造方法

案例

被注释的部分是lombok会帮助我们自动生成的代码。

@Slf4j
@Slf4j
public class Test {
    // private static final Logger log=LoggerFactory.getLogger(Test.class);
    public static void main(String[] args) {
        log.info("Hello world");
    }
}
@Builder
        Test test = Test.builder()
                .id(id)
                .page(page)
                .build();
 
@Data
@Builder
public class Test {
 
    private String id;
 
    private String page;
    
    /**
     @java.beans.ConstructorProperties({"id", "page"})
    Test(Long id, int page) {
        this.id = id;
        this.page = page;
    }
 
    public static TestBuilder builder() {
        return new TestBuilder();
    }
 
    public TestBuilder toBuilder() {
        return new TestBuilder().id(this.id).page(this.page);
    }
 
    public static class TestBuilder {
        private Long id;
        private int page;
 
        TestBuilder() {}
 
        public TestBuilder id(Long id) {
            this.id = id;
            return this;
        }
 
        public TestBuilder page(int page) {
            this.page = page;
            return this;
        }
 
        public Test build() {
            return new Test(id, page);
        }
 
        public String toString() {
            return "Test.TestBuilder(id=" + this.id + ", page="
                + this.page")";
        }
    */
}
@SneakyThrows
    @Test(expected = RuntimeException.class)
    @SneakyThrows
    public void test_throw_exception() {
        when(HttpClientUtil.get(anyString()).thenThrow(new RuntimeException());
        api.test("nice");
    }
@Data
@Data
public class User {
 
    private Long id;
 
    private String username;
 
    private String password;
    
    
    /**
    public User() {}
 
    public Long getId() {return this.id;}
 
    public String getUsername() {return this.username;}
 
    public String getPassword() {return this.password;}
 
    public void setId(Long id) {this.id = id; }
 
    public void setUsername(String username) {this.username = username; }
 
    public void setPassword(String password) {this.password = password; }
 
    public boolean equals(Object o) {
        if (o == this) { return true; }
        ...
        return true;
    }
 
    public int hashCode() {
        final int PRIME = 59;
        int result = 1;
        final Object $id = this.getId();
        result = result * PRIME + ($id == null ? 43 : $id.hashCode());
        final Object $username = this.getUsername();
        ...
        return result;
    }
 
    protected boolean canEqual(Object other) {return other instanceof User;}
 
    public String toString() {
        return "User(id=" + this.getId() + ...+ ")";
    }
    */
	}
}
@Value
@Value
public class Test {
 
    (private final) Long id;
 
    (private final) String page;
    
    /**
    @java.beans.ConstructorProperties({"id", "page"})
    public Test(Long id, String page) {
        this.id = id;
        this.page = page;
    }
 
    public Long getId() {return this.id;}
 
    public String getPage() {return this.page;}
 
    public boolean equals(Object o) {
        if (o == this) { return true; }
          ...
        return true;
    }
 
    public int hashCode() {
        final int PRIME = 59;
        int result = 1;
        final Object $id = this.getId();
        result = result * PRIME + ($id == null ? 43 : $id.hashCode());
        ...
        return result;
    }
 
    public String toString() {
            return "Test.TestBuilder(id=" + this.id + ", page="
                + this.page")";
        }
    */
}

原文链接：https://blog.csdn.net/xue_xiaofei/article/details/128397765