Lombok 官方文档

Posted 2020-09-10

原理：根据实体类上的标签，生成一个新的实体类。然后再进行编译

官方文档地址：https://projectlombok.org/features/

文档首页：

======================================================================================================

val

Finally! Hassle-free final local variables.

@NonNull

or: How I learned to stop worrying and love the NullPointerException.

@Cleanup

Automatic resource management: Call your close() methods safely with no hassle.

@Getter / @Setter

Never write public int getFoo() {return foo;} again.

@ToString

No need to start a debugger to see your fields: Just let lombok generate a toString for you!

@EqualsAndHashCode

Equality made easy: Generates hashCode and equals implementations from the fields of your object.

@NoArgsConstructor, @RequiredArgsConstructor and @AllArgsConstructor

Constructors made to order: Generates constructors that take no arguments, one argument per final / non-null field, or one argument for every field.

@Data

All together now: A shortcut for @ToString, @EqualsAndHashCode, @Getter on all fields, and @Setter on all non-final fields, and @RequiredArgsConstructor!

@Value

Immutable classes made very easy.

@Builder

... and Bob‘s your uncle: No-hassle fancy-pants APIs for object creation!

@SneakyThrows

To boldly throw checked exceptions where no one has thrown them before!

@Synchronized

synchronized done right: Don‘t expose your locks.

@Getter(lazy=true)

Laziness is a virtue!

@Log

Captain‘s Log, stardate 24435.7: "What was that line again?"

Configuration system

Lombok, made to order: Configure lombok features in one place for your entire project or even your workspace.

Experimental features

Here be dragons: Extra features which aren‘t quite ready for prime time yet.

If you‘d rather read a longer tutorial, here is a great tutorial (including a walkthrough through some of the above features) written by Michael Kimberlin.

The documentation above is a lot easier to follow, but if you want to build your own transformations, or you want to add javadoc to lombok.jar in your IDE, you can also check out the javadoc.

Running Lombok

On eclipse

Execute lombok.jar (doubleclick it, or run java -jar lombok.jar). Follow instructions.

On javac (and maven, ant, and other build tools)

Include lombok.jar on the classpath as you compile. That‘s all there is to it!
Lombok hosts its own maven repository, so adding lombok to maven is very simple. full instructions are here.

On GWT (Google Widget Toolkit)

See gwt setup.

On javadoc, and other source-based tools

Use delombok first, then run javadoc or GWT on the delombok-ed code.

Running delombok

Delombok copies your source files to another directory, replacing all lombok annotations with their desugared form. So, it‘ll turn @Getter back into the actual getter. It then removes the annotation. This is useful for all sorts of reasons; you can check out what‘s happening under the hood, if the unthinkable happens and you want to stop using lombok, you can easily remove all traces of it in your source, and you can use delombok to preprocess your source files for source-level tools such as javadoc and GWT. More information about how to run delombok, including instructions for build tools can be found at the delombok page.

credits | Copyright ? 2009-2016 The Project Lombok Authors, licensed under the MIT license.

 

 

 

======================================================================================================

 

jar包名称：lombok.jar    既可以放项目lib目录下直接编译，也可以直接安装

 

======================================================================================================

 

使用示例：

代码：

 1 import lombok.AllArgsConstructor;
 2 import lombok.Data;
 3 import lombok.NoArgsConstructor;
 4 import lombok.RequiredArgsConstructor;
 5 
 6 @Data
 7 @AllArgsConstructor
 8 @NoArgsConstructor
 9 //@RequiredArgsConstructor
10 public class Student {
11     private int id;
12     private String name;
13 }

测试类代码：

 

 

 

这就是  这些注解的作用----