MapStruct entry use

MapStruct Getting Started Use Cases

The following are commonly used examples. You can change them according to your needs.

@Data
public class UserDO{
    private int age;
    private String name;
    private Role role;
    private String date;
}


@Data
public class UserDTO{
    private int dtoAge;
    private String dtoName;
    private Guest guest;
    private Date date;
}

import .*;
 import ;


 @Mapper
 public interface UserConvert{
    
     UserConvert INSTANCE = ();
    
     //Method 1 Return value method
     UserDO DTOConvertDO(UserDTO dto);
    
     //Method 2: Add annotations to parameters
     void DTOConvertDO(UserDTO dto,@MappingTarget UserDO user)
     
     //Automatically ignore the empty value of the source object
     @BeanMapping(nullValuePropertyMappingStrategy = )
     UserDO DTOConvertDO(UserDTO dto);
        
     //resultType specifies the return target type, ignoreByDefault = true: ignore all unmapped attributes in the target type CarDto.
     //mappingControl =: If there are unmatched properties, filter them without reporting errors or warnings
     @BeanMapping(resultType = ,ignoreByDefault = true, mappingControl = ) UserDO DTOConvertDO(UserDTO dto);
        
     //Mapping between attributes with the same name, the dtoName of the specified dto is mapped to the name in Do
     @Mapping(source = "dtoName",target = "name")
     //Conditional mapping, mapping and assignment if you are older than 18 years old
     @Mapping(condition = "java(() >= 18)", target = "age")
     //Ignore the specified value mapping
     @Mapping(source="guest",ignore=true)
     void DTOConvertDO(UserDTO dto,@MappingTarget UserDO user)
        
     //Mapping between properties with the same name, including the assignment of the second-level object properties below it.  dateFotmat specifies the time format
     @Mappings({
         @Mapping(source = "dtoName",target = "name"),
         @Mapping(source = "dtoAge",target = "age")
         @Mapping(source = "",target = "")
         @Mapping(source = "date",target = "date",dateFotmat="yyyy-MM-dd")
     })
    void DTOConvertDO(UserDTO dto,@MappingTarget UserDO user)
        
    // When it is null, no value is assigned, you can set it one by one.
    @Mapping(target = "dtoName", source = "name", defaultExpression = "java(null)")
    void DTOConvertDO(UserDTO dto,@MappingTarget UserDO user)
        
        
    //Collection mapping
    @MapMapping(valueDateFormat="yyyy-MM-dd")
    void DTOConvertDO(Map<String,Date> dto,@MappingTarget Map<String,String> map)
 }

Note:

@BeanMapping(nullValuePropertyMappingStrategy = ): Ignore mapping assignments to null values

@Mappingtarget: Specify the assignment target object, where is the assignment.

@Mapping(source = "dtoName", target = "name"): Specify the mapping relationship, assign attributes with different names, assign the dtoName under UserDTO to the name under UserDO

@Mappings({
@Mapping(source = "dtoName",target = "name"),
@Mapping(source = "dtoAge",target = "age")
}): Specify the mapping relationship, multiple times.