设置LocalDateTime的值。使用ModelMapper进行映射时，将now（）转换为两个字段

Question

我必须通过ModelMapper将我从UI获得的DTO映射到我的实体。

在使用ModelMapper之前，我有以下方法：

private Operation map(OperationForm src) {
    Operation operation = new Operation();
    LocalDateTime NOW = LocalDateTime.now();
    operation.setOperationKey(OperationKey.of(src.getLegalEntityId(), 
                             src.getEmployeeId(), 
                             NOW));  // here
    operation.setIndividualId(src.getIndividualId());
    operation.setKey(src.getLegalEntityId() + "_" 
                     + src.getEmployeeId() + "_" 
                     + NOW);         // and here

    return operation;
}

在这种情况下，我必须通过LocalDateTime.now（）生成新的LocalDateTime，并在两个不同的字段中使用它。

所以，我尝试这样配置ModelMapper：

public OperationFormMapper(ModelMapper modelMapper) {
    Converter<OperationForm, OperationKey> operationKeyConverter = (context) -> OperationKey.of(context.getSource().getLegalEntityId(), 
                context.getSource().getEmployeeId(), 
                LocalDateTime.now()); // generate new LocalDateTime to 
                                      // destination instance

    Converter<Operation, String> keyConverter = (context) -> {
        Operation src = context.getSource();
        return src.getOperationKey().getLegalEntityId() + "_" 
               + src.getOperationKey().getEmployeeId() + "_" 
               + src.getOperationKey().getOperationDate();
    }; // converter for my purpose
       // I am trying to get value not from source, 
       // but from destination instance, hoping that 
       // all needed fields are already mapped

    this.modelMapper = modelMapper;

    this.modelMapper.addMappings(new PropertyMap<OperationForm, Operation>() {

        @Override
        protected void configure() {
            using(operationKeyConverter).map(source, destination.getOperationKey());
            map().setIndividualId(source.getIndividualId());
            map().setOperationStatus(Operation.OperationStatus.CREATED);

            using(keyConverter).map(destination, destination.getKey()); 
            // trying to get all needed data from already mapped fields
        }
    });
}

它不起作用并不奇怪。我得到了NullPointerException。显然，在我试图获取关键字段的值时，字段仍然没有映射。

那么，有人知道如何处理这一时刻，并使ModelMapper也为我的案例工作吗？或者至少有一些方法可以完全定制映射过程并创建整个方法，该方法将由ModelMapper用于映射（或者使其使用我现有的方法）？

更新：

我的实体：

public class Operation {
    private OperationKey operationKey;
    private Long individualId;
    private String operationStatus;
    private String operationResult;
    private String guardCardSeries;
    private String guardCardNumber;
    private LocalDateTime guardCardStartDate;
    private LocalDateTime guardCardEndDate;
    private String resultMessage;
    private String key;
}

用户界面中的我的DTO：

public class OperationForm implements Serializable {
    private Long legalEntityId;
    private Long employeeId;
    private Long individualId;
}

我的Cassandra DB复合密钥：

public class OperationKey {
    private final Long legalEntityId;
    private final Long employeeId;
    private final LocalDateTime operationDate;
}

我只是通过删除持久性注释简化了它们。

Answer 1

看来我找到了解决办法。

我的ModelMapper配置现在。

public OperationFormMapper(ModelMapper modelMapper) {
        this.modelMapper = modelMapper;

        Converter<OperationForm, Operation> converter = context -> {
            OperationForm src = context.getSource();
            Operation dest = new Operation();

            final LocalDateTime NOW = LocalDateTime.now();
            dest.setOperationKey(OperationKey.of(src.getLegalEntityId(), src.getEmployeeId(), NOW));
            dest.setIndividualId(src.getIndividualId());
            dest.setKey(src.getLegalEntityId() + "_" + src.getEmployeeId() + "_" + NOW);

            return dest;
        };

        this.modelMapper.addConverter(converter);
    }

我创建了转换器并将我的方法推入其中。现在它起作用了。