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读取具有一对多关系的JPA模型时生成不完整的JSON错误

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读取具有一对多关系的JPA模型时生成不完整的JSON错误,json,jackson,jax-rs,eclipselink,one-to-many,Json,Jackson,Jax Rs,Eclipselink,One To Many,我正在使用JPA EclipseLink对用例和PainPoint之间的一对多关系进行建模。我可以很好地插入值。此后，我使用JAX-RS使用GET方法检索数据。GET方法失败，错误为生成不完整的JSON 控制台日志： @NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")}) @Id @GeneratedValue(strategy = GenerationType.AUTO)

我正在使用JPA EclipseLink对用例和PainPoint之间的一对多关系进行建模。我可以很好地插入值。此后，我使用JAX-RS使用GET方法检索数据。GET方法失败，错误为生成不完整的JSON

控制台日志：

@NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "UseCaseID")
private int UseCaseID;

@Column(name = "Description")
private String Description;

@OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();

@NamedQueries({@NamedQuery(name = "getAllPainPoints", query = "SELECT c FROM PainPoint c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "PainPointID")
private int PainPointID;

@Column(name = "PainPointDescription")
private String PainPointDescription;

@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
private UseCase usecase;

UseCase useCase = new UseCase("Description 1");
PainPoint painPoint1 = new PainPoint("Pain Point 1", useCase);
useCase.getPainPoints().add(painPoint1);
em.persist(useCase);

@GET
@Path("/")
public List<UseCase> getUseCases() {

List<UseCase> retVal = null;

EntityManagerFactory emf = Utility.getEntityManagerFactory();
EntityManager em = emf.createEntityManager();

retVal = em.createNamedQuery("getAllUseCases").getResultList();

return retVal;
}
  • [EL Fine]：在用例（UseCaseID，描述）中插入值（？，） 绑定=>[1，说明]
  • [EL Fine]：插入痛点 （PainPointID，PainPointDescription，USECASE_ID）值（？，？）绑定 =>[2，痛点1，1]
  • [EL Fine]：选择UseCaseID，从USECASE中选择描述
  • 2017年11月17日下午7:16:22 org.eclipse.yasson.internal.Marshaller:Generating 不完全JSON
用例：

@NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "UseCaseID")
private int UseCaseID;

@Column(name = "Description")
private String Description;

@OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();

@NamedQueries({@NamedQuery(name = "getAllPainPoints", query = "SELECT c FROM PainPoint c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "PainPointID")
private int PainPointID;

@Column(name = "PainPointDescription")
private String PainPointDescription;

@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
private UseCase usecase;

UseCase useCase = new UseCase("Description 1");
PainPoint painPoint1 = new PainPoint("Pain Point 1", useCase);
useCase.getPainPoints().add(painPoint1);
em.persist(useCase);

@GET
@Path("/")
public List<UseCase> getUseCases() {

List<UseCase> retVal = null;

EntityManagerFactory emf = Utility.getEntityManagerFactory();
EntityManager em = emf.createEntityManager();

retVal = em.createNamedQuery("getAllUseCases").getResultList();

return retVal;
}
数据加载器：

@NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "UseCaseID")
private int UseCaseID;

@Column(name = "Description")
private String Description;

@OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();

@NamedQueries({@NamedQuery(name = "getAllPainPoints", query = "SELECT c FROM PainPoint c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "PainPointID")
private int PainPointID;

@Column(name = "PainPointDescription")
private String PainPointDescription;

@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
private UseCase usecase;

UseCase useCase = new UseCase("Description 1");
PainPoint painPoint1 = new PainPoint("Pain Point 1", useCase);
useCase.getPainPoints().add(painPoint1);
em.persist(useCase);

@GET
@Path("/")
public List<UseCase> getUseCases() {

List<UseCase> retVal = null;

EntityManagerFactory emf = Utility.getEntityManagerFactory();
EntityManager em = emf.createEntityManager();

retVal = em.createNamedQuery("getAllUseCases").getResultList();

return retVal;
}
UseCaseService:

@NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "UseCaseID")
private int UseCaseID;

@Column(name = "Description")
private String Description;

@OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();

@NamedQueries({@NamedQuery(name = "getAllPainPoints", query = "SELECT c FROM PainPoint c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "PainPointID")
private int PainPointID;

@Column(name = "PainPointDescription")
private String PainPointDescription;

@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
private UseCase usecase;

UseCase useCase = new UseCase("Description 1");
PainPoint painPoint1 = new PainPoint("Pain Point 1", useCase);
useCase.getPainPoints().add(painPoint1);
em.persist(useCase);

@GET
@Path("/")
public List<UseCase> getUseCases() {

List<UseCase> retVal = null;

EntityManagerFactory emf = Utility.getEntityManagerFactory();
EntityManager em = emf.createEntityManager();

retVal = em.createNamedQuery("getAllUseCases").getResultList();

return retVal;
}

@GET
@路径（“/”）
公共列表getUseCases（）{
列表retVal=null；
EntityManagerFactory emf=Utility.getEntityManagerFactory（）；
EntityManager em=emf.createEntityManager（）；
retVal=em.createNamedQuery（“getAllUseCases”）.getResultList（）；
返回返回；
}
在循环引用的getter方法或任何其他派生字段上添加注释@jsonbttransient（包：javax.json.bind.annotation.jsonbttransient）。这相当于用于XML生成的@XmlTranisent注释，并将防止转换为JSON进入无限循环

我想这取决于您的工具集，但对于使用NetBeans的我来说，当自动生成实体类时，会添加XML注释，但不会添加JSON注释。根据上面所说的，只需将每个@xmltransive与等效的@JsonbTransient进行匹配即可。您可以添加以下Maven依赖项

<dependency>
    <groupId>javax.json.bind</groupId>
    <artifactId>javax.json.bind-api</artifactId>
    <version>1.0</version>
</dependency>


javax.json.bind

这很可能是由循环引用引起的，有两种方法处理此问题，如中所述：


  • @杰索尼奥雷
    • 

  • @JsonManagedReference和@JsonBackReference
    • 

    
我建议您采用第二种方法，并添加以下两种注释，以避免循环引用问题：
    

    @OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JsonBackReference                ///// ADD THIS ANNOTATION
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();


@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
@JsonManagedReference              ///// ADD THIS ANNOTATION
private UseCase usecase;

    

    @OneToMany（mappedBy=“usecase”，cascade=CascadeType.ALL，fetch=FetchType.EAGER）
@JsonBackReference//添加此批注
private Collection painPoints=new ArrayList（）；
@许多酮
@JoinColumn（name=“USECASE\u ID”，referencedColumnName=“UseCaseID”）
@JsonManagedReference///添加此批注
私人用例用例；

    

    
更多信息：
    

    @NamedQueries({@NamedQuery(name = "getAllUseCases", query = "SELECT c FROM UseCase c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "UseCaseID")
private int UseCaseID;

@Column(name = "Description")
private String Description;

@OneToMany(mappedBy="usecase", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
private Collection<PainPoint> painPoints = new ArrayList<PainPoint>();

    

    @NamedQueries({@NamedQuery(name = "getAllPainPoints", query = "SELECT c FROM PainPoint c")})

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@NotNull
@Column(name = "PainPointID")
private int PainPointID;

@Column(name = "PainPointDescription")
private String PainPointDescription;

@ManyToOne
@JoinColumn (name="USECASE_ID", referencedColumnName="UseCaseID")
private UseCase usecase;

    

    UseCase useCase = new UseCase("Description 1");
PainPoint painPoint1 = new PainPoint("Pain Point 1", useCase);
useCase.getPainPoints().add(painPoint1);
em.persist(useCase);

    

    @GET
@Path("/")
public List<UseCase> getUseCases() {

List<UseCase> retVal = null;

EntityManagerFactory emf = Utility.getEntityManagerFactory();
EntityManager em = emf.createEntityManager();

retVal = em.createNamedQuery("getAllUseCases").getResultList();

return retVal;
}

    

      

    • 

    • 

    • 

    • 

    显然，JSON生成与JPA API无关，所以为什么不调试到JSON生成的位置，使用什么代码……我想我应该在原始帖子中包含这些信息。但似乎有某种循环递归搜索正在进行。例如，用例有痛点。PainPoint与用例相关联。所以JSON出现了错误。。。不知道如何在一对多关系中绕过它。我删除了引用用例的PainPoint对象上的getter和setter，现在它似乎可以工作了。哈哈，应该猜到了。希望我不会遇到其他问题。我使用了来自和works的@JsonIdentityInfo，谢谢。@AndréLuítomaszdio我很高兴它对您有所帮助。