Mapstruct：如何映射层次结构，其中子对象是列表并且具有列表属性

Question

我有一个场景，需要从 DTO 对象映射到域对象。

我已经简化了下面的场景

class TopLevel {
    private String attr1;
    private String attr2;
    private List<SecondLevel> secondLevel = new ArrayList<>();
    
    class SecondLevel {
        private String attr3;
        private JsonNode additionalConfig;
        private List<String> stringList = new ArrayList<>();
        private List<ThirdLevel> thirdLevel = new ArrayList<>();

        class ThirdLevel {
            private String attr4;
            private String attr5;
            private List<String> anotherList = new ArrayList<>();
            
        }  

    }  

}

这需要映射到下面的域结构

class TopLevelDomain {
    private ID guid1; //Generated Guid
    private String attr1;
    private String attr2;
    private List<SecondLevelDomain> secondLevelDomain = new ArrayList<>();
}

class SecondLevelDomain {
    private ID guid1; //From TopLevel Domain
    private ID guid2; //Generated Guid
    private String attr3;
    private String stringListAsString; // List of Strings needs to be converted to string (JSON format)
    private String additionalConfig; //JSON node needs to be converted to String (JSON format)
    private List<ThirdLevelDomain> thirdLevelDomain = new ArrayList<>();
}

class ThirdLevelDomain {
    private ID guid1; //From TopLevel Domain
    private ID guid2; //From SecondLevel Guid
    private ID guid3; //New Guid
    private String attr4;
    private String attr5;
    private String anotherListAsString; // List of Strings needs to be converted to string (JSON format)

}

现在我需要进行qualifiedByName/Named映射来获取第一级的GUID。另外，我还需要其他 2 个子级别的类似 GUID。

@Mapping(source = "topLevel", target = "guid1", qualifiedByName = "mapGuid1")
@Mapping(source = "topLevel", target = "secondLevelDomain", qualifiedByName = "secondLevelDomain")
TopLevelDomain toTopLevel(TopLevel topLevel)

如果我执行类似上面代码的操作，我看不出如何访问第二级属性 attr3、additionalConfig 和 @Mapping 注释中的列表 stringList

另外，如何访问第三级属性 attr4、attr5 和 anotherList。我需要直接映射字符串矩阵，分配 guid 并为字符串和 JSONNode 列表进行一些自定义映射

Answer 1

您想要在这里做两件事。

1. 添加额外的映射方法。 Mapstruct 将使用用户定义的映射方法来生成新的映射方法。
2. 使用@AfterMapping 传递生成的GUID。

// custom mapping annotations
TopLevelDomain toTopLevel( TopLevel topLevel );

// custom mapping annotations
SecondLevelDomain toSecondLevel( TopLevel.SecondLevel secondLevel );

// custom mapping annotations
ThirdLevelDomain toThirdLevel( TopLevel.SecondLevel.ThirdLevel thirdLevel );

// custom mapping methods

@AfterMapping
default void handleGuidTransfer( TopLevelDomain topLevel ){
    for ( SecondLevelDomain secondLevel: topLevel.getSecondLevelDomain() ) {
        secondLevel.setGuid1( topLevel.getGuid1() );
        for ( ThirdLevelDomain thirdLevel: secondLevel.getThirdLevelDomain() ) {
            thirdLevel.setGuid1( topLevel.getGuid1() );
            thirdLevel.setGuid2( secondLevel.getGuid2() );
        }
    }
}