Mapstruct：根据某个字段的值忽略集合中的某些元素

Question

我有这些豆子：

public class Company {
    private String name;
    private List<Address> addresses;
    ...some other fields...
}

public class Address {
    private String street;
    private String city;
    private boolean deleted;
    ...some other fields...
}

我还有一些用于这些豆子的 DTO

public class CompanyDto {
    private String name;
    private List<AddressDto> addresses;
    ...some other fields...
}

public class AddressDto {
    private String street;
    private String city;
    ...some other fields...
}

（请注意，AddressDto 类缺少该deleted字段）

我正在使用 Mapstruct 将这些 bean 映射到它们的 DTO。映射器是这样的：

@Mapper
public interface CompanyMapper {
    CompanyDto companyToCompanyDto(Company company);
    List<AddressDto> ListAddressToListAddressDto(List<Address> addresses);
}

现在，在映射中我想忽略deleted字段为 的Address 实例true。我有办法实现这一目标吗？

Answer 1

I'm not sure if you can get it out of the box from MapStruct features.

From Documentation:

The generated code will contain a loop which iterates over the source collection, converts each element and puts it into the target collection. - https://mapstruct.org/documentation/stable/reference/html/#mapping-collections

I want to ignore the Address instances whose deleted field is true - to do it you need your own implementation of mapping this collection.

Below an example of CompanyMapper

@Mapper
public interface CompanyMapper {
    CompanyDto companyToCompanyDto(Company company);
    AddressDto addressToAddressDto(Address address);

    default List<AddressDto> addressListToAddressDtoList(List<Address> list) {
        return list.stream()
                   .filter(address -> !address.isDeleted())
                   .map(this::addressToAddressDto)
                   .collect(Collectors.toList());
    }
}