如果没有null，Java Spring不会返回DTO对象？

Question

我有一个Java实现Override方法，该方法根据输入的参数从2个微服务返回DTO对象结果。我可以得到过滤后的搜索结果，但是如果不满足第二个服务条件，我会收到'null'，我想获得一个结果，其中无论如何都不返回空对象。我如何才能返回满足所有指定参数的结果？下面，我提供了使用“ Swagger”接收到的响应的屏幕截图，并且代码被截断了，它可以解决所有问题。我是否需要使用ObjectMapper或类似@JsonInclude(Include.NON_NULL)的东西，但是我可以在服务植入和DTO对象中使用它吗？任何进一步的建议或想法反弹将不胜感激。我进一步根据先前的问题Java pass variable into mapped DTO method?

Swagger Response

代码段

    @Override
public Page<ProfileCreditDTO> findProfileBySelectedParameters(String username, Integer gender, Integer profileType, Integer orientation, Boolean online, Double profileCredit, Integer creditMode, Double creditTotal, Pageable pageable) {
    Page<Profile> searchData= profileRepository.findByAllParameters(username, gender, profileType, orientation, online, pageable);
    Page<ProfileCreditDTO> searchProfileData=null;
    if(searchData != null)
        searchProfileData = searchData.map(x -> this.convertProfileToProfileCreditDTO(x, profileCredit, creditMode, creditTotal));
    return searchProfileData;
}


public ProfileCreditDTO convertProfileToProfileCreditDTO(final Profile theProfile, Double profileCredit, Integer creditMode, Double creditTotal)  {
    if(theProfile == null)
        return null;
    ProfileCreditDTO theDTO= new ProfileCreditDTO();
    theDTO.setProfile(theProfile);
    CreditDTO theCreditDto = profileCreditClient.findClientByProfileId(theProfile.getId(), profileCredit, creditMode, creditTotal);
    log.error(String.valueOf(theCreditDto));
    if (theCreditDto != null)
        theDTO.setCredit(theCreditDto);
    else {
        return null;
    }

    return theDTO;
}

已更新我尝试将@JsonInclude(Include.NON_NULL)添加到ProfileCredit DTO中仍然没有，也已将相同的内容添加到CreditDTO中。

ProfileCredit DTO

 @Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
@JsonInclude(JsonInclude.Include.NON_NULL)
public class ProfileCreditDTO {
    // profile fields
    private Long profileId;
    @Size(min = 2, max = 50)
    private String username;
    private Integer gender;
    private Integer profileType;
    private Integer orientation;
    private boolean online;


    // Credit fields
    private Long creditId;
    @Column(unique = true)
    private Double profileCredit;  //X
    private Integer creditMode;
    private Integer creditCheck;
private Double creditTotal;

/**
 * set the profile derrived data
 * @param profile
 */
public void setProfile(final Profile profile){
    this.setProfileId(profile.getId());
    this.setUsername(profile.getUsername());
    this.setGender(profile.getGender());
    this.setProfileType(profile.getProfileType());
    this.setOrientation(profile.getOrientation());
    this.setOnline(profile.isOnline());
}

/**
 * Set the credit aspect
 * @param credit
 */
public void setCredit(final CreditDTO credit){
    this.setCreditId(credit.getId());
    this.setProfileId(credit.getProfileId());
    this.setProfileCredit(credit.getProfileCredit());
    this.setCreditMode(credit.getCreditMode());
    this.setCreditTotal(credit.getCreditTotal());

}

当我在实现中未指定return null;时，响应如下所示。如您所见，所有返回的对象都满足条件1，但不满足条件2则返回空对象字段。

Answer 1

您作为元素的“对象”不能直接从页面中删除。您可以做的是，从页面中获取内容，该内容将是一个列表，然后根据您的条件从列表中删除该元素，然后使用页面所需的数据字段创建一个新页面。

代替

    @Override
public Page<ProfileCreditDTO> findProfileBySelectedParameters(String username, Integer gender, Integer profileType, Integer orientation, Boolean online, Double profileCredit, Integer creditMode, Double creditTotal, Pageable pageable) {
    Page<Profile> searchData= profileRepository.findByAllParameters(username, gender, profileType, orientation, online, pageable);
    Page<ProfileCreditDTO> searchProfileData=null;
    if(searchData != null)
        searchProfileData = searchData.map(x -> this.convertProfileToProfileCreditDTO(x, profileCredit, creditMode, creditTotal));
    return searchProfileData;
}

尝试

   @Override
public Page<ProfileCreditDTO> findProfileBySelectedParameters(String username, Integer gender, Integer profileType, Integer orientation, Boolean online, Double profileCredit, Integer creditMode, Double creditTotal, Pageable pageable) {
    Page<Profile> searchData= profileRepository.findByAllParameters(username, gender, profileType, orientation, online, pageable);
    Page<ProfileCreditDTO> searchProfileData=null;
    if(searchData != null)
        searchProfileData = searchData.map(x -> this.convertProfileToProfileCreditDTO(x, profileCredit, creditMode, creditTotal));

    List modifiedAppList = searchProfileData.getContent().stream().filter(v -> v !=null).collect(Collectors.toList()); //Will filter your search result and put it into a list

    Page<ProfileCreditDTO> filteredList = new PageImpl<>(modifiedAppList, new PageRequest(0, searchProfileData.getSize()), searchProfileData.getTotalElements()); //Will put your filtered list back into page

    return  filteredList; //Returns filtered result

}