Java Spring 不 return DTO 对象如果为空？

Question

我有一个 Java 实现覆盖方法，根据输入的参数，returns DTO 对象来自 2 个微服务。

我能够获得经过过滤的搜索结果，但是在不满足第二个服务条件的情况下，我收到 'null' 我想获得一个结果，其中空对象不是 returned whatsoever.How 我能到 return 满足所有指定参数的结果？

下面我提供了我使用 "Swagger" 收到的响应的屏幕截图以及执行所有操作的代码片段。
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？
如有任何进一步的建议或想法，我们将不胜感激。

我进一步完善了我之前的问题

招摇响应

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
我已经尝试将 @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，所有满足条件 1 的对象都得到 returned，但不满足条件 2 的空对象字段被 returned。

Answer 1

您的 "objects" 元素不能直接从页面中删除。你可以做的是，从页面中获取内容，这将是一个列表，然后根据你的条件从列表中删除元素，然后创建一个新页面，其中包含页面所需的数据字段。

而不是

    @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

}

从 Spring Data Rest - How to remove an element from a Page? 得到了这个问题的答案只是修改了代码和措辞的一点，因为答案已经在现场;）

Answer 2

添加这个

@JsonInclude(JsonInclude.Include.NON_NULL)

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