Quartz 4

Lombok

3 min read

Project Lombok is a java library that automatically plugs into your editor and build tools, spicing up your java.

spice (up):

to add interest or excitement to (something) — usually + up

  • They looked for advice on how to spice up their living room.他们征求意见，看如何给客厅增添点情趣。
  • We need to spice up our relationship.我们需要调剂一下我们的关系。
  • We tried to spice things up by putting on some lively music.我们想放点欢快的音乐来助兴。
@Data
public class Account {
    private int id;
    private String name;
    private int age;
    private String gender;
    private String password;
    private String description;
}

上面代码class反编译后的的代码为

//  
// Source code recreated from a .class file by IntelliJ IDEA  
// (powered by FernFlower decompiler)  
//  
 
public class Account {  
    private int id;  
    private String name;  
    private int age;  
    private String gender;  
    private String password;  
    private String description;  
  
    public static void main(String[] args) {  
        new Account();  
    }  
  
    @Generated  
    public Account() {  
    }  
  
    @Generated  
    public int getId() {  
        return this.id;  
    }  
  
    @Generated  
    public String getName() {  
        return this.name;  
    }  
  
    @Generated  
    public int getAge() {  
        return this.age;  
    }  
  
    @Generated  
    public String getGender() {  
        return this.gender;  
    }  
  
    @Generated  
    public String getPassword() {  
        return this.password;  
    }  
  
    @Generated  
    public String getDescription() {  
        return this.description;  
    }  
  
    @Generated  
    public void setId(int id) {  
        this.id = id;  
    }  
  
    @Generated  
    public void setName(String name) {  
        this.name = name;  
    }  
  
    @Generated  
    public void setAge(int age) {  
        this.age = age;  
    }  
  
    @Generated  
    public void setGender(String gender) {  
        this.gender = gender;  
    }  
  
    @Generated  
    public void setPassword(String password) {  
        this.password = password;  
    }  
  
    @Generated  
    public void setDescription(String description) {  
        this.description = description;  
    }  
  
    @Generated  
    public boolean equals(Object o) {  
        // ....
    }  
  
    @Generated  
    protected boolean canEqual(Object other) {  
        return other instanceof Account;  
    }  
  
    @Generated  
    public int hashCode() {  
	    // ...
    }  
  
    @Generated  
    public String toString() {  
        int var10000 = this.getId();  
        return "Account(id=" + var10000 + ", name=" + this.getName() + ", age=" + this.getAge() + ", gender=" + this.getGender() + ", password=" + this.getPassword() + ", description=" + this.getDescription() + ")";  
    }  
}

可以看到lombok干涉了编译的过程

那么Lombok是如何做到一个注解就包揽了代码生成工作的呢？这里又要说到我们Java的编译过程，它可以分成三个阶段：

Drawing 2025-07-18 00.24.35.excalidraw

⚠ Switch to EXCALIDRAW VIEW in the MORE OPTIONS menu of this document. ⚠ You can decompress Drawing data with the command palette: ‘Decompress current Excalidraw file’. For more info check in plugin settings under ‘Saving’

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Text Elements

java
source
code

010111010101100010

Binary Files

Parse and Enter

Annotation
Processing

Analyse and
Generate

Link to original

  1. 所有源文件会被解析成语法树。
  2. 调用注解处理器。如果注解处理器产生了新的源文件，新文件也要进行编译。
  3. 最后，语法树会被分析并转化成类文件。
    Lombok会在上述的第二阶段，执行lombok.core.AnnotationProcessor，它所做的工作就是我们上面所说的，修改语法树，并将注解对应需要生成的内容全部添加到类文件中，这样，我们即使没有在源代码中编写的内容，也会存在于生成出来的class文件中。

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