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");}
}
@BuilderTest 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)@SneakyThrowspublic 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