Lombok plug-in

Lombok plug-in unit

lombok Plug in introduction

lombok Is a plug-in , The purpose is to use annotations to give fields in your class , Automatically add attribute constructors ,ToString Method ,Equals Methods, etc. .

The more convenient point is , When you change fields ,lombok Changes will occur immediately to maintain consistency with your code .

frequently-used lombok Note introduction

• @Getter ： Can automatically generate parameters getter Method .

• @Setter ： Can automatically generate parameters setter Method

• @ToString ： call toString() Method , You can output the values of all attributes in the entity class

• @RequiredArgsConstructor： Will generate a containing constant , And the logo NotNull How to construct the variables of . The generated constructor is private private. This one is seldom used .

• @EqualsAndHashCode

  • 1. It will generate equals and hashCode Method

  • 2. Non static attributes are used by default

  • 3. Can pass exclude Parameters exclude attributes that do not need to be generated

    @EqualsAndHashCode(exclude = {“ Fields in the table 1”, “ Fields in the table 2”})

  • 4. Can pass of Parameter to specify the attribute to be generated

    @EqualsAndHashCode(of = {“ Fields in the table 1”, “ Fields in the table 2”})

  • 5. By default, it does not call the methods of the parent class , Only use the attributes defined by this class to operate , have access to callSuper=true To solve , Will be in @Data I'll explain it in .

• @Data： This annotation is actually a combination of the above five annotations —@Getter、@Setter、@RequiredArgsConstructor、@ToString、@EqualsAndHashCode

• @NoArgsConstructor： Generate a parameterless construction method .

• @AllArgsConstructor： Generate a constructor that contains all variables .

• @Value： This annotation should be consistent with Spring Of @Value Annotation distinction ,Spring Is to read the content from the configuration file , This annotation is that all fields in the class are declared as private final type , Only generates Getter Method , Will not generate Setter Method , Rarely used .

• @Cleanup： It is mainly used to turn off the use of resources .

idea install lombok plug-in unit

First we need to install IntelliJ IDEA Medium lombok plug-in unit .

open IntelliJ IDEA Then click... In the menu bar File–>Settings, Or use shortcut keys Ctrl+Alt+S Go to the settings page

Restart after installation idea—【 I am idea Version is 2021】

lombok Use of plug-ins

@Data
@AllArgsConstructor
@NoArgsConstructor
    //  Used to represent the mapping relationship between entity classes and database tables , When the entity class name is different from the name of the table, you must add  @TableName
@TableName("user")
public class User {
    
//  Indicates that the database self increment strategy is used 
    @TableId(type = IdType.AUTO)
    private Long id;
//  When the attribute name in the entity class is inconsistent with the field name in the database , have access to   annotation ：@TableField  To represent the mapping relationship 
    @TableField("name")
    private String username;
    private Integer age;
    private String email;
// @TableField(exist = false)  Express   There is no such field in the database table , Mapping transformation sql Statement will not spell this field 
    @TableField(exist = false)
    private Date birthday;


    public User(String name, Integer age, String email) {
    
        this.username = name;
        this.age = age;
        this.email = email;
    }
}

me = name;
this.age = age;
this.email = email;
}
}