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JSON和Hibernate JPA的无限递归

input spring-boot hibernate json java

dEs12ZER · 技术社区 · 6 年前

使用spring Boot,在尝试将JPA对象转换为JSON时,我不断遇到以下错误:

nested exception is 
  `org.springframework.http.converter.HttpMessageNotWritableException:
     Could not write JSON: Infinite recursion (StackOverflowError); 
    nested exception is com.fasterxml.jackson.databind.
JsonMappingException: Infinite recursion (StackOverflowError)
 (through reference chain: interv.Entities.AppUser["projects"]->org.hibernate.collection.internal.PersistentBag[0]->interv.Entities.Project["appUser"]->interv.Entities.AppUser["projects"]->org.hibernate.collection.internal.Persis`

根据堆栈溢出中的一些解决方案,我在结束时添加了注释 @JsonIgnoreProperties,因此我的实体项目如下所示:

@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Project implements Serializable{

        @Id @GeneratedValue
        private long id;
        private String intitule;
        private String description;

        @OneToMany(mappedBy = "project" , fetch = FetchType.EAGER)
       @Fetch(value = FetchMode.SUBSELECT)
        @JsonIgnoreProperties("contrats")
        private Collection<Contrat> contrats;

        @ManyToOne
        @JoinColumn(name = "Id_appUser")
        @JsonIgnoreProperties("appUser")
        private AppUser appUser;
 }

api restful如下所示:

    import java.util.List;

@RestController
public class ProjectsController {

    @Autowired
    private ProjectRepo projectRepo;

    @RequestMapping(path = "/ListProjects", method = RequestMethod.GET)
    public List<Project> getProjects(){
        return projectRepo.findAll();
    }

我尝试了其他注释,但始终出现相同的错误:

在弧延伸中,我得到:

200好的

分析JSON数据时出错

JSON输入意外结束

提前感谢您的帮助:)。

编辑:

文件AppUser。Java语言

@Entity
@Data
@AllArgsConstructor @NoArgsConstructor
public class AppUser implements Serializable {

    @Id @GeneratedValue
    private Long id;
    @Column(unique = true)
    private String username;
    private String password;
    @ManyToMany(fetch = FetchType.EAGER)
    private Collection<AppRole> roles = new ArrayList<>();

    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    private Collection<Project> projects = new ArrayList<>();


    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    private Collection<Intervention> interventions = new ArrayList<>();

    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    private Collection<Contrat> contrats = new ArrayList<>();

}

1 回复 | 直到 6 年前

SEY_91 6 年前

出现这些问题是因为在生成JSON时存在无限循环。您可以使用@JsonManagedReference和@JsonBackReference来解决无限递归。

@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Project implements Serializable{

        @Id @GeneratedValue
        private long id;
        private String intitule;
        private String description;

        @OneToMany(mappedBy = "project" , fetch = FetchType.EAGER)
       @Fetch(value = FetchMode.SUBSELECT)
        @JsonIgnoreProperties("contrats")
        private Collection<Contrat> contrats;

        @ManyToOne
        @JoinColumn(name = "Id_appUser")
        @JsonBackReference
        private AppUser appUser;
 }

应用程序用户

@Entity
@Data
@AllArgsConstructor @NoArgsConstructor
public class AppUser implements Serializable {

    @Id @GeneratedValue
    private Long id;
    @Column(unique = true)
    private String username;
    private String password;
    @ManyToMany(fetch = FetchType.EAGER)
    private Collection<AppRole> roles = new ArrayList<>();

    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    @JsonManagedReference
    private Collection<Project> projects = new ArrayList<>();


    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    private Collection<Intervention> interventions = new ArrayList<>();

    @OneToMany(mappedBy = "appUser" , fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)
    private Collection<Contrat> contrats = new ArrayList<>();

}