Mapstruct-为映射属性找到模糊的映射方法

Question

我正在使用mapstruct从一个DTO映射到另一个。我有多个默认方法，但是其中两个具有返回值String且使用与输入参数相同的类的默认方法给我“使用Java Mapstruct的模糊映射方法”错误。我在这里添加代码的相关部分：

@Mappings({
     @Mapping(source = "programInstance", target = "title", qualifiedByName = "title"),
     @Mapping(source = "programInstance", target = "seriesName", qualifiedByName = "seriesName"),
     @Mapping(source = "programInstance", target = "season", qualifiedByName = "season"),
     @Mapping(source = "programInstance", target = "epNumber", qualifiedByName = "epNumber"),
 })
 DTO1 mapDTOs (DTO2 dto2);

  @Named("title")
default String mapTitle(Program programInstance) {
    Optional<String> title = Utils.getObject(() -> programInstance.getTitle().getDescriptions().get(0).getValue());
    if (title.isPresent())
        return title.get();
    return null;
}
@Named("seriesName")
default String mapSeriesName(Program programInstance) {
    Optional<String> seriesName = Utils.getObject(() -> programInstance.get(0).getProgram().getTitle().getDescriptions().get(0).getValue());
    if (seriesName.isPresent())
        return seriesName.get();
    return null;
}
 @Named("season")
default Integer mapSeasonNumber(Program programInstance) {
    Optional<Integer> season = Utils.getObject(() -> programInstance.get(0).getSeasonOf().get(0).getOrderNo());
    if (season.isPresent())
        return season.get();
    return null;
}

@Named("epNumber")
default Integer mapEpNumber(Program programInstance) {
    Optional<Integer> epNumber = Utils.getObject(() -> programInstance.getEpOf().get(0).getOrderNo());
    if (epNumber.isPresent())
        return epNumber.get();
    return null;
}

错误是

找到了用于将属性“ Program programInstance”映射到java.lang.String的模糊映射方法：java.lang.String mapTitle（），java.lang.String mapSeriesName（）。

Answer 1

我检查了您的示例。问题是您尝试定位的字段是字符串类型。

所以：

public class IvpVodOfferStatusDTO {

    private String seasonNumber;
    private String episodeNumber;
} 

MapStruct 尝试将其与您提供的签名匹配：

 @Named("season")
default Integer mapSeasonNumber(Program programInstance) {
    Optional<Integer> season = Utils.getObject(() -> programInstance.get(0).getSeasonOf().get(0).getOrderNo());
    if (season.isPresent())
        return season.get();
    return null;
}

@Named("epNumber")
default Integer mapEpNumber(Program programInstance) {
    Optional<Integer> epNumber = Utils.getObject(() -> programInstance.getEpOf().get(0).getOrderNo());
    if (epNumber.isPresent())
        return epNumber.get();
    return null;
}

MapStruct 具有预定义的尝试顺序：

1. 用户提供的映射方法
2. 直接（类型 source -target 相同）
3. 映射方法（内置）
4. 类型转换

如果这一切都失败了 MapStruct 会尝试执行许多 2 步方法：

5. 映射方法 - 映射方法
6. 映射方法——类型转换
7. 类型转换-映射方法

At 6. it finds 2 qualifying methods (Program to String). It's probably an error in MapStruct that it selects methods that do not qualify (need to check whether this is intentional) by the @Named. Otherwise, I'll write an issue.

The most easy solution is: adapt the target:

public class IvpVodOfferStatusDTO {

    private Integer seasonNumber;
    private Integer episodeNumber;
}

What is probably what you intend (I guess).. Otherwise you could change the signature not to return an Integer but a String