MapStruct高级用法

MapStruct高级用法

1. 依赖注入（Using dependency injection）

   @Mapper(componentModel = SPRING)
   public interface SpringMapper {
       SpringMapper MAPPER = Mappers.getMapper(SpringMapper.class);
   
       PersonDTO personDoToDTO(Person person);
   }
   

   public static final class ComponentModel {
       private ComponentModel() {
       }
       public static final String DEFAULT = "default";
       public static final String CDI = "cdi";
       public static final String SPRING = "spring";
       public static final String JSR330 = "jsr330";
       public static final String JAKARTA = "jakarta";
   }
   

   示例代码：com.yxxmg.mapstruct.convert.SpringMapper

2. 组合多个映射

   @Mapper(imports = Date.class)
   public interface PersonMapper {
       PersonMapper MAPPER = Mappers.getMapper(PersonMapper.class);
   
       @Mapping(target = "personName", source = "name")
       @Mapping(target = "id", ignore = true)
       // 忽略id,不进行映射
       PersonDTO personDoToDTO(Person person);
   
       @Mapping(target = "personName", source = "name") // 指定映射
       @Mapping(target = "describe", source = "describe", defaultValue = "默认值") // 设置默认值
       @Mapping(target = "updateDate", expression = "java(new java.util.Date())") // 表达式 java
       @Mapping(target = "modifyDate", expression = "java(new Date())")
       @Mapping(target = "createDate", source = "createTime", dateFormat = "YYYY-MM-DD") // 格式化
       @Mapping(source = "source", target = "source", numberFormat = "#0.00")
       PersonDTO convert2(Person person);
   }
   

   示例代码：com.yxxmg.mapstruct.convert.PersonMapper

3. 嵌套对象属性映射

    @Mapper
    public interface CustomerMapper {
   
        @Mapping( target = "name", source = "record.name" )
        @Mapping( target = ".", source = "record" )
        @Mapping( target = ".", source = "account" )
        Customer customerDtoToCustomer(CustomerDto customerDto);
    }
   

4. 迭代器以及参数传递

   使用@IterableMapping、@Context

   @Mapper
   public interface MenuMapper {
       MenuMapper MAPPER = Mappers.getMapper(MenuMapper.class);
   
       @Mapping(target = "parentId", source = "parentId")
       Menu convert(String parentId, MenuDTO menuDTO);
   
       @IterableMapping(qualifiedByName = "convertDTO")
       List<Menu> convert(@Context String parentId, List<MenuDTO> menuDTOList);
   
       @Named("convertDTO")
       default Menu convertDTO(@Context String parentId, MenuDTO menuDTO) {
           return convert(parentId, menuDTO);
       }
   
   

   示例代码：com.yxxmg.mapstruct.convert.MenuMapper

5. 隐式转换

   例如可以定义默认方法将枚举转换成字符串或者数值，所有枚举字段会自动隐式转换，上述的例子中已经体现，就不举例说明

6. 映射参数到目标对象上@MappingTarget

   @Mapper
   public interface SourceTargetMapper {
       SourceTargetMapper MAPPER = Mappers.getMapper(SourceTargetMapper.class);
   
       void toEntity(ParentDto s, @MappingTarget ParentEntity t);
   
       @Mapper(unmappedTargetPolicy = ReportingPolicy.IGNORE)
       interface LenientMapper {
   
           void toEntity(ChildDto s, @MappingTarget ChildEntity t);
       }
   }
   

   示例代码:com.yxxmg.mapstruct.mappingtarget.SourceTargetMapper

7. 深克隆

   @Mapper(mappingControl = DeepClone.class)
   public interface Cloner {
       Cloner MAPPER = Mappers.getMapper(Cloner.class);
   
       CustomerDto clone(CustomerDto customerDto);
   }
   

   编译后

   @Generated(
       value = "org.mapstruct.ap.MappingProcessor",
       date = "2024-05-30T09:22:14+0800",
       comments = "version: 1.5.0.RC1, compiler: javac, environment: Java 1.8.0_401 (Oracle Corporation)"
   )
   public class ClonerImpl implements Cloner {
   
       @Override
       public CustomerDto clone(CustomerDto customerDto) {
           if ( customerDto == null ) {
               return null;
           }
   
           CustomerDto customerDto1 = new CustomerDto();
   
           customerDto1.setId( customerDto.getId() );
           customerDto1.setCustomerName( customerDto.getCustomerName() );
           customerDto1.setOrders( orderItemDtoListToOrderItemDtoList( customerDto.getOrders() ) );
           customerDto1.setStock( orderItemKeyDtoOrderItemDtoMapToOrderItemKeyDtoOrderItemDtoMap( customerDto.getStock() ) );
   
           return customerDto1;
       }
   
       protected OrderItemDto orderItemDtoToOrderItemDto(OrderItemDto orderItemDto) {
           if ( orderItemDto == null ) {
               return null;
           }
   
           OrderItemDto orderItemDto1 = new OrderItemDto();
   
           orderItemDto1.setName( orderItemDto.getName() );
           orderItemDto1.setQuantity( orderItemDto.getQuantity() );
   
           return orderItemDto1;
       }
   
       protected List<OrderItemDto> orderItemDtoListToOrderItemDtoList(List<OrderItemDto> list) {
           if ( list == null ) {
               return null;
           }
   
           List<OrderItemDto> list1 = new ArrayList<OrderItemDto>( list.size() );
           for ( OrderItemDto orderItemDto : list ) {
               list1.add( orderItemDtoToOrderItemDto( orderItemDto ) );
           }
   
           return list1;
       }
   

   示例代码：com.yxxmg.mapstruct.clone.mapper.Cloner

8. 后续发现其他高级特性待补充…
   示例代码相关地址

   https://gitee.com/youxiaxiaomage/java-practices