java.lang.StackOverflowError : null for the jpa saveAll

Question

我在将 spring-boot 与 JPA 存储库集成时收到这些错误 这是代码

@CrossOrigin(origins = "http://localhost:4200")
@RestController
@RequestMapping("/api")
public class EmpController {

    @Autowired
    private CrudRepo crud;

    @Autowired
    private AddrCrudRepo addr;

    @Autowired
    private EntityManager entity;

    //@Autowired
    //private ModelMapper mapper;

private static int count = 0;


    @Bean
    public ModelMapper model() {
        return new ModelMapper();
    }

    //@Autowired
//  public EmpController(ModelMapper mapper) {
//      this.mapper = mapper;
//  }



    @RequestMapping(path = "/post-addr", method = RequestMethod.POST)
    public List<AddressModel> postAddr(@Valid @RequestBody List<AddressRequest> addr1){
    //  crud.findById(id)

        //AddressModel list = new AddressModel();

        EmployeeModel emp = new EmployeeModel();

        System.out.println("CALLING THE MAPPER "+addr1);
        List<AddressModel> addr_list = ObjectMapperUtils.mapAll(addr1, AddressModel.class);

        System.out.println("CALLED THE MAPPER "+addr_list);
        addr_list.forEach((a) -> {

            crud.findById(a.getEmpId()).ifPresent((b) -> {
                System.out.println(this.count++);
                a.setEmp_id(b);
                b.getAddress().add(a);

            });
        });


//      AddressModel addr_list = model().map(addr1, AddressModel.class);
//      
//      crud.findById(addr1.getEmp_id()).ifPresent((b) -> {
//          addr_list.setEmp_id(b);
//          
//      });`enter code here`
        System.out.println(addr_list.size());
        List<AddressModel> addr3 =  addr.saveAll(addr_list);
        System.out.println(addr3);
         return addr_list;

    }

postAddr 中出现错误方法，当它返回 List<AddressModel> 时这是AddressModel

@Entity
@Table(name="Emp_Address")
public class AddressModel  implements Serializable{

    @Column(name="address_id")
    @Id
    private Integer address_id;

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

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

    @Transient
    private Integer empId;

    @ManyToOne
    @JoinColumn(name="emp_id")
    private EmployeeModel emp_id;

    public AddressModel() {

    }

//getter and setter

和EmployeeModel

@Entity
@Table(name="Employee")
public class EmployeeModel implements Serializable{

    @Column(name="Emp_id")
    @Id
    private Integer emp_id;

    @Column(name="Emp_Name")
    private String emp_name;

    @OneToMany(mappedBy="emp_id")
    private Collection<AddressModel> address = new ArrayList<>();

    public EmployeeModel() {

    }

//getter and setters

因此，虽然 saveAll 正确完成，但是当 postAddr 方法返回 List 时，它会抛出 StackOverflow

Answer 1

出现此 StackOverflow 错误是因为两个类生成的 toString 方法相互循环依赖。

EmployeeModel 尝试打印 AddressModel，但 AddressModel 再次尝试打印 EmployeeModel，因此出现错误。

尝试从 EmployeeModel 类的 toString 方法中删除 AddressModel 或相反，从 toString 中删除 EmployeeModel AddressModel 类的 方法。