Mapstruct - 映射器对象需要对象字段的值映射答案

【问题标题】：Mapstruct - mapper object needs valuemapping of an object fieldMapstruct - 映射器对象需要对象字段的值映射
【发布时间】：2020-05-09 07:06:26
【问题描述】：

我有一个对象A，我正在尝试将其映射到B。现在这个A 有一个名为field1 的枚举，其中包含一些值。我想使用@ValueMappings 将它们映射到B 中的其他枚举值。以下是我到目前为止的代码：

@Mapping(source = "field1", target = "field1", nullValuePropertyMappingStrategy = IGNORE)
@Mapping(source = "field2", target = "field2", nullValuePropertyMappingStrategy = IGNORE)
@ValueMappings({
    @ValueMapping(source = "field1.some1", target = "diff1"),
    @ValueMapping(source = "field1.some2", target = "diff1"),
    @ValueMapping(source = "field1.some3", target = "diff1"),
    @ValueMapping(source = "field1.some4", target = "diff2"),
})
B map(A a);

当我尝试编译它时，我得到了错误：

error: The following constants from the property "A.field1 field1" enum have no corresponding constant in the "B field1" enum and must be be mapped via adding additional mappings: diff1, diff2.

【问题讨论】：

标签： mapstruct

【解决方案1】：

解决此问题的一种方法是执行以下操作：

@Mapper(componentModel = "spring",  uses = {SomeUtil.class}, unmappedTargetPolicy = ReportingPolicy.IGNORE)
public interface Mapper {
    @Mapping(source = "field1", target = "field1", nullValuePropertyMappingStrategy = IGNORE)
    @Mapping(source = "field2", target = "field2", nullValuePropertyMappingStrategy = IGNORE)
    B map(A a);
}

在 SomeUtil.class 中：

@Mapper(componentModel = "spring")
public interface SomeUtil {

    @ValueMappings({
        @ValueMapping(source = "field1.some1", target = "diff1"),
        @ValueMapping(source = "field1.some2", target = "diff1"),
        @ValueMapping(source = "field1.some3", target = "diff1"),
        @ValueMapping(source = "field1.some4", target = "diff2"),
    })
    b.field1 map(a.field1 field);
}

【讨论】：