Lombok @Data @Builder

怼烎@ 2023-10-05 23:34 87阅读 0赞

## Lombok 功能 ##

@Data 注解，省去实体类中大量的get()和set()方法。

@Builder 注解，创建生成器。

各种其他注解

## 使用效果 ##

![594c997541f041949faee0fd655b3ba2.png][]

然后就可以正常使用实体类了。

## 依赖 ##

使用@Data等注解前，需要先安装Lombok插件。安装方法会在后文介绍。

<dependency>
    			<groupId>org.projectlombok</groupId>
    			<artifactId>lombok</artifactId>
    			<optional>true</optional>
    		</dependency>

## @Data ##

### 实体类 ###

package com.example.datademo.web;
    
    import java.util.Date;
    import java.util.List;
    
    import javax.validation.constraints.Max;
    import javax.validation.constraints.Min;
    import javax.validation.constraints.NotBlank;
    import javax.validation.constraints.NotEmpty;
    import javax.validation.constraints.NotNull;
    import javax.validation.constraints.Size;
    
    import org.springframework.format.annotation.DateTimeFormat;
    import org.springframework.format.annotation.DateTimeFormat.ISO;
    
    import lombok.Data;
    
    @Data
    public class StudentVO {
    
    	@NotBlank
    	@Size(min = 2, max = 5)
    	private String name;
    
    	@NotNull
    	@Min(18)
    	@Max(200)
    	private Integer age;
    
    	@NotEmpty
    	private List<Integer> courseIds;
    
    	@NotNull
    	@DateTimeFormat(iso = ISO.DATE)
    	private Date graduationDate;
    
    }

### 接口内调用 ###

package com.example.datademo.web;
    
    import javax.validation.Valid;
    
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("example")
    public class ExampleController {
    
    	@GetMapping("test")
    	public String test() {
    		return "test ok!";
    	}
    
    	@GetMapping("student")
    	public StudentVO getStudent(@Valid StudentVO vo) {
    		String name = vo.getName();
    		vo.setName(name);
    		return vo;
    	}
    
    }

### 接口内调用效果 ###

![91d8ac63830d43b192cd05df86de030e.png][]

### 单独调用 get() 和 set() 方法 ###

![3739a72f4f8a420eaa4eaaa0614b84f2.png][]

实体类的 get()、set() 方法是可以正常使用的。

### 单独调用 toString() 方法 ###

### ![0042e3307e38468b850b867f90c1283f.png][] ###

## @Builder ##

### 代码 ###

package com.example.datademo.web;
    
    import lombok.Builder;
    
    @Builder
    public class Dialog {
    
    	private String tile;
    	private String content;
    	private String positiveButtonText;
    	private String negativeButtonText;
    
    	interface OnClickListenter {
    		void onClick();
    	}
    
    	private OnClickListenter positiveButtonListener;
    
    	public void run() {
    		positiveButtonListener.onClick();
    	}
    
    }

![b78b53011f114a3384fea69488bbf666.png][]

### 使用 ###

public static void main(String[] args) {
    		Dialog dialog = Dialog.builder()
    				.tile("标题")
    				.content("内容")
    				.positiveButtonText("确定")
    				.negativeButtonText("取消")
    				.positiveButtonListener(() -> {
    					System.out.println("回调");
    				})
    				.build();
    		System.out.println("运行");
    		dialog.run();
    	}

### 结果 ###

![176760bcfee54e588990af03f7c959f6.png][]

## @Singular ##

生成一个方法，用来向集合内添加一个元素。需要和@Builder一起用。

package com.example.vodemo.employee;
    
    import java.util.List;
    
    import lombok.Builder;
    import lombok.Data;
    import lombok.Singular;
    
    @Data
    @Builder
    public class Student1 {
    	private Long id;
    
    	private String name;
    
    	@Singular("addHobby")
    	private List<String> hobby;
    
    	public static void main(String[] args) {
    		Student1 student = Student1.builder().id(300L).name("赵三").addHobby("篮球").addHobby("游泳").build();
    		System.out.println(student.toString());
    	}
    }

![d74505324225498f94b39ceb4ebf63c5.png][]

## val 和 var ##

public void testValAndVar() {
    		val student = new StudentVO();
    //		student = new StudentVO(); // val不可变
    		var student2 = new StudentVO();
    		student2 = new StudentVO();
    	}

## @FieldNameConstants ##

package com.example.vodemo.employee;
    
    import lombok.Data;
    import lombok.experimental.FieldNameConstants;
    
    @Data
    @FieldNameConstants
    public class StudentVO {
    	private Long id;
    	private String name;
    }

public void field() {
    		System.out.println(StudentVO.Fields.id);
    		System.out.println(StudentVO.Fields.name);
    	}

## @Accessors(chain = true) - 实验性注解 ##

package com.example.vodemo.employee;
    
    import lombok.Data;
    import lombok.experimental.Accessors;
    
    @Data
    @Accessors(chain = true)
    public class Student2 {
    	private Long id;
    
    	private String name;
    
    	public static void main(String[] args) {
    		Student2 vo = new Student2();
    		vo.setId(200L).setName("赵二");
    		System.out.println(vo.toString());
    	}
    }

![600c48fed06440c9826835b2faaf7e3f.png][]

## @Accessors(fluent = true) - 实验性注解 ##

package com.example.vodemo.employee;
    
    import lombok.Data;
    import lombok.experimental.Accessors;
    
    @Data
    @Accessors(fluent = true)
    public class Student {
    	private Long id;
    	private String name;
    
    	public static void main(String[] args) {
    		Student student = new Student();
    		student.id(100L).name("张三");
    		System.out.println(student.toString());
    		System.out.println(student.id());
    		System.out.println(student.name());
    	}
    }

![432cae1988e449969f85e5ea55631050.png][]

## 其他注解 ##

> Equals方法和HashCode方法包含哪些字段
> 
>  *  @EqualsAndHashCode(of = \{ "id", "name" \})
> 
> 构造器的访问级别
> 
>  *  AccessLevel.PUBLIC

package com.example.vodemo.employee;
    
    import java.util.List;
    
    import lombok.AccessLevel;
    import lombok.AllArgsConstructor;
    import lombok.Builder;
    import lombok.Data;
    import lombok.EqualsAndHashCode;
    import lombok.NoArgsConstructor;
    import lombok.Singular;
    import lombok.experimental.Accessors;
    import lombok.experimental.FieldNameConstants;
    
    @Data
    @EqualsAndHashCode(of = { "id", "name" })
    @NoArgsConstructor(access = AccessLevel.PUBLIC)
    @AllArgsConstructor(access = AccessLevel.PRIVATE)
    public class StudentVO {
    	private Long id;
    	private String name;
    }

package com.example.vodemo.employee;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    
    import lombok.Cleanup;
    import lombok.SneakyThrows;
    import lombok.Synchronized;
    
    public class Test2 {
    	@SneakyThrows
    	public void testThrow() {
    		Thread.sleep(1000);
    	}
    
    	@Synchronized
    	public void sync() {
    
    	}
    
    	public void cleanup(String pathname) throws IOException {
    		@Cleanup
    		FileInputStream stream = new FileInputStream(pathname);
    	}
    }

## Lombok安装及依赖 ##

@Data注解，需要将Lombok插件安装到IDE中，并在pom.xml中添加依赖。

### 1. 官网下载jar包 ###

[Download (projectlombok.org)][Download _projectlombok.org]

![44a7b3eb58994dfea736439af283ad0f.png][]

### 2.安装 ###

#### Windows平台 ####

双击下载好的lombak.jar，安装步骤如下：

关闭弹出的警告窗口，点击 Specify location…

![1f02a6a1d5ca4748918cb5e65fdac23c.png][]

![558ebf4bc4884363899212dac21172cc.png][]

D:\\app\\sts

这是我的STS的安装目录

![5f27581962c5473aa021309ac858c382.png][]

![aebbabae6347463cb8541b51e0f82f1a.png][]

重启STS ，安装就可以生效了。

#### Mac平台 ####

1.  进入到SpringToolSuite4.app包内容，将lombok.jar复制到和SpringToolSuite4.ini同级目录下；
2.  在当前目录下启动终端，运行java -jar lombok.jar，选择到SpringToolSuite4.ini，点击install即可完成安装；

![9fe35bd0a1f94370b604d1156e757642.png][]

![14b0caa031ee408ab17fa025184f1875.png][] ![7dc34552ea87456ea2e08782b860e7e5.png][]

### 引入Lombok依赖 ###

已存在的项目，可以直接在pom.xml中添加依赖。之后可能需要clean一下项目。

新建springboot项目时，可以直接选择添加lombok依赖。

![1a0c5d8549154cc1a1d7dea18a65fa2b.png][]

## 参考 ##

[Lombok官网 - 注解（稳定版）][Lombok_ -]

[594c997541f041949faee0fd655b3ba2.png]: https://img-blog.csdnimg.cn/594c997541f041949faee0fd655b3ba2.png
[91d8ac63830d43b192cd05df86de030e.png]: https://img-blog.csdnimg.cn/91d8ac63830d43b192cd05df86de030e.png
[3739a72f4f8a420eaa4eaaa0614b84f2.png]: https://img-blog.csdnimg.cn/3739a72f4f8a420eaa4eaaa0614b84f2.png
[0042e3307e38468b850b867f90c1283f.png]: https://img-blog.csdnimg.cn/0042e3307e38468b850b867f90c1283f.png
[b78b53011f114a3384fea69488bbf666.png]: https://img-blog.csdnimg.cn/b78b53011f114a3384fea69488bbf666.png
[176760bcfee54e588990af03f7c959f6.png]: https://img-blog.csdnimg.cn/176760bcfee54e588990af03f7c959f6.png
[d74505324225498f94b39ceb4ebf63c5.png]: https://img-blog.csdnimg.cn/d74505324225498f94b39ceb4ebf63c5.png
[600c48fed06440c9826835b2faaf7e3f.png]: https://img-blog.csdnimg.cn/600c48fed06440c9826835b2faaf7e3f.png
[432cae1988e449969f85e5ea55631050.png]: https://img-blog.csdnimg.cn/432cae1988e449969f85e5ea55631050.png
[Download _projectlombok.org]: https://projectlombok.org/download
[44a7b3eb58994dfea736439af283ad0f.png]: https://img-blog.csdnimg.cn/44a7b3eb58994dfea736439af283ad0f.png
[1f02a6a1d5ca4748918cb5e65fdac23c.png]: https://img-blog.csdnimg.cn/1f02a6a1d5ca4748918cb5e65fdac23c.png
[558ebf4bc4884363899212dac21172cc.png]: https://img-blog.csdnimg.cn/558ebf4bc4884363899212dac21172cc.png
[5f27581962c5473aa021309ac858c382.png]: https://img-blog.csdnimg.cn/5f27581962c5473aa021309ac858c382.png
[aebbabae6347463cb8541b51e0f82f1a.png]: https://img-blog.csdnimg.cn/aebbabae6347463cb8541b51e0f82f1a.png
[9fe35bd0a1f94370b604d1156e757642.png]: https://img-blog.csdnimg.cn/9fe35bd0a1f94370b604d1156e757642.png
[14b0caa031ee408ab17fa025184f1875.png]: https://img-blog.csdnimg.cn/14b0caa031ee408ab17fa025184f1875.png
[7dc34552ea87456ea2e08782b860e7e5.png]: https://img-blog.csdnimg.cn/7dc34552ea87456ea2e08782b860e7e5.png
[1a0c5d8549154cc1a1d7dea18a65fa2b.png]: https://img-blog.csdnimg.cn/1a0c5d8549154cc1a1d7dea18a65fa2b.png
[Lombok_ -]: https://projectlombok.org/features/