通过mapstruct实现对象之间的相互转换

1.导入依赖

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.4.2.Final</version>
</dependency>
<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct-processor</artifactId>
    <version>1.4.2.Final</version>
</dependency>

2.编写转换类

@Mapper
public interface FollowUpDtoMapper {
    
    FollowUpDtoMapper INSTANCES = Mappers.getMapper(FollowUpDtoMapper.class);

    /**
     * dto 转 vo
     * @param dto dto
     * @return vo
     */
    FollowUpVO dtoToVo(FollowUpDTO dto);
    
}

这里关键的就是@Mapper这个注解，当我们写好之后，就会将我们的dto转为vo。当我们项目在编译阶段，就会自动帮我们生成实现类。

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2022-01-25T15:50:13+0800",
    comments = "version: 1.4.2.Final, compiler: javac, environment: Java 11.0.2 (Oracle Corporation)"
)
public class FollowUpDtoMapperImpl implements FollowUpDtoMapper {

    @Override
    public FollowUpVO dtoToVo(FollowUpDTO dto) {
        if ( dto == null ) {
            return null;
        }

        FollowUpVO followUpVO = new FollowUpVO();

        followUpVO.setId( dto.getId() );
        followUpVO.setFollowUpTime( dto.getFollowUpTime() );
        followUpVO.setFollowUpInformation( dto.getFollowUpInformation() );

        return followUpVO;
    }
}

3.使用方法

FollowUpVO vo = FollowUpDtoMapper.INSTANCE.dtoToVo(dto);

4.特殊用法@Mapping

@Mapper
public interface FollowUpDtoMapper {
    
    FollowUpDtoMapper INSTANCES = Mappers.getMapper(FollowUpDtoMapper.class);

    /**
     * dto 转 vo
     * @param dto dto
     * @return vo
     */
    //这里代表dto转vo时，忽略vo中的column字段
    @Mapping(target = "column", ignore = true)
    //将dto中的name字段的值赋给vo中的productName字段
    @Mapping(source = "name", target = "productName")
    //BigDecimal转换成字符串
    @Mapping(target = "blance", numberFormat = "#.00元")
    //字符串转换成int   
    @Mapping(target = "age", numberFormat = "#岁")
    FollowUpVO dtoToVo(FollowUpDTO dto);
	
	//多数据源映射
	//这里代表将dto1中的productName属性的值赋给vo的name字段，将dto2中的productDesc属性的值赋给vo的desc字段
	@Mapping(source = "name", target = "dto1.productName")
	@Mapping(source = "desc", target = "dto2.productDesc")
	FollowUpVO dtoToVo(FollowUpDTO1 dto1, FollowUpDTO2 dto2);
}

特殊用法这些基本够用了，就不举例了。