MapStruct：與HashMap中的條目處理源

Question

這裏是我的源對象：

public class Record { 

    public final long captureTime; 
    public final String environnement; 
    public final String bundle; 
    public final String type; 
    public final String id; 
    public final Map<String,Object> meta; 

} 

這是我的目標對象：

public class MappedRecord { 

    public final long captureTime; 
    public final String environnement; 
    public final String bundle; 
    public final String type; 
    public final String id; 
    public final String ip; 
    public final String server; 

} 

我的映射如下所示：

public interface RecordMapper { 

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


    @Mappings({ 
     @Mapping(source = "captureTime", target = "captureTime"), 
     @Mapping(source = "environnement", target = "environnement"), 
     @Mapping(source = "bundle", target = "bundle"), 
     @Mapping(source = "type", target = "type"), 
     @Mapping(source = "id", target = "id"), 
     @Mapping(expression = "java((String) r.meta.get(\"ip\"))", target = "ip"), 
     @Mapping(expression = "java((String) r.meta.get(\"server\"))", target = "server"), 
    }) 

    MappedRecord toMappedRecord(Record r); 

} 

現在它運行良好，但我想知道是否有一個更「優雅」的方式來設置地圖項作爲源。因爲有了這個，我沒有設法使用「qualifiedByName」屬性添加轉換函數，它看起來只能在指定「源」時才能工作。我誤解了什麼？

我嘗試沒有滿意的結果以下方法：

• 覆蓋getter方法中的特定字段我Record類

• 添加一個轉換功能與「qualifiedByName」屬性。例如：

  @Named("metaGetter") 
  default String dataGetter (String property) { 
      return (String) r.meta.get(property); 
  } 
  

  但顯然這不會編譯，因爲屬性名稱無效作爲適當的來源。

謝謝你的時間。

Answer 1

自己寫的預選賽：

public class MappingUtil { 
    @Qualifier 
    @Target(ElementType.METHOD) 
    @Retention(RetentionPolicy.SOURCE) 
    public @interface Ip { 
    } 
    @Qualifier 
    @Target(ElementType.METHOD) 
    @Retention(RetentionPolicy.SOURCE) 
    public static @interface Server { 
    } 
    @Ip 
    public String ip(Map<String, Object> in) { 

     return (String)in.get("ip"); 
    } 
    @Server 
    public String server(Map<String, Object> in) { 

     return (String)in.get("server"); 
    } 
} 

，然後只需添加到映射：

@Mapper(uses = MappingUtil.class) 
public interface SourceTargetMapper { 

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

    @Mappings({ 
     @Mapping(source = "map", target = "ip", qualifiedBy = MappingUtil.Ip.class), 
     @Mapping(source = "map", target = "server", qualifiedBy = MappingUtil.Server.class), 
    }) 
    Target toTarget(Source s); 
}