MapStruct + lombok实现优雅实体转换

1、是什么？

MapSturct 是一个生成类型安全， 高性能且无依赖的 JavaBean 映射代码的注解处理器（annotation processor）。

抓一下重点：

注解处理器
可以生成 JavaBean 之间那的映射代码
类型安全， 高性能， 无依赖性
从字面的理解， 我们可以知道， 该工具可以帮我们实现 JavaBean 之间的转换， 通过注解的方式。

同时， 作为一个工具类，相比于手写， 其应该具有便捷， 不容易出错的特点。

具体见https://mapstruct.org/

2、如何接入

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.3.1.Final</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.8</version>
</dependency>

lombok和mapstruct要匹配，最好与官网保持一致

<build>
   <plugins>
      <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.8.1</version>
         <configuration>
            <source>1.8</source>
            <target>1.8</target>
            <annotationProcessorPaths>
               <path>
                  <groupId>org.mapstruct</groupId>
                  <artifactId>mapstruct-processor</artifactId>
                  <version>${org.mapstruct.version}</version>
               </path>
               <path>
                  <groupId>org.projectlombok</groupId>
                  <artifactId>lombok</artifactId>
                  <version>${lombok.version}</version>
               </path>
            </annotationProcessorPaths>
         </configuration>
      </plugin>
   </plugins>
</build>

3、demo类

转换接口

@Mapper
public interface ExpCardMapper {

    ExpCardMapper MAPPER = Mappers.getMapper(ExpCardMapper.class);

    ExpCardDetailModel convertExpCardDetail(ExpCardDetailDto detailDto);

    ExpCardModel convertExpCard(ExpCardDto expCardDto);

    ExpCardBatchModel convertExpCardBatch(ExpCardBatchDto batchDto);
}

生成具体实现类（框架自动生成，无需关注）

public class ExpCardMapperImpl implements ExpCardMapper {
    public ExpCardMapperImpl() {
    }

    public ExpCardDetailModel convertExpCardDetail(ExpCardDetailDto detailDto) {
        if (detailDto == null) {
            return null;
        } else {
            ExpCardDetailModelBuilder expCardDetailModel = ExpCardDetailModel.builder();
            expCardDetailModel.card(this.convertExpCard(detailDto.getCard()));
            expCardDetailModel.cardBatch(this.convertExpCardBatch(detailDto.getCardBatch()));
            return expCardDetailModel.build();
        }
    }

    public ExpCardModel convertExpCard(ExpCardDto expCardDto) {
        if (expCardDto == null) {
            return null;
        } else {
            ExpCardModelBuilder expCardModel = ExpCardModel.builder();
            expCardModel.amount(expCardDto.getAmount());
            expCardModel.cardKey(expCardDto.getCardKey());
            expCardModel.code(expCardDto.getCode());
            expCardModel.streamNumber(expCardDto.getStreamNumber());
            return expCardModel.build();
        }
    }

    public ExpCardBatchModel convertExpCardBatch(ExpCardBatchDto batchDto) {
        if (batchDto == null) {
            return null;
        } else {
            ExpCardBatchModelBuilder expCardBatchModel = ExpCardBatchModel.builder();
            expCardBatchModel.price(batchDto.getPrice());
            expCardBatchModel.productCode(batchDto.getProductCode());
            expCardBatchModel.fv(batchDto.getFv());
            expCardBatchModel.monthCard(batchDto.isMonthCard());
            return expCardBatchModel.build();
        }
    }
}

具体使用

ExpCardDetailModel detailModel = ExpCardMapper.MAPPER.convertExpCardDetail(expCardRes.getData());

4、高级用法

https://mapstruct.org/documentation/stable/reference/html/