Question

开始进入Spring Boot，并使用jpa存储库来持久保存本地mysql数据库，而我的插入遇到麻烦。我将其简化为我的用户和任务类，一个用户可以有一个任务，并且我在任务类中使用@ManyToOne注释进行一个方向映射。在邮递员中调用端点时，出现错误，并且跟踪显示user_id列为空（这是用户映射的列）。

要调试，我在实际taskRepo.save（task）方法的task服务类中设置了一个断点，看来user_id实际上是。我尝试了一对多和多对一的双向映射，但按选项进行映射却无济于事。

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(unique = true)
private Long id;

private Long postId;

@Column(unique = true, nullable = false)
private String username;

@Column(unique = true, nullable = false, name = "email")
private String email;

@Column(nullable = false)
private String password;





@Id
@GeneratedValue(strategy =GenerationType.IDENTITY)
@Column(name = "id", nullable = false)
private Long id;

@Column(name = "taskName", nullable = false)
private String taskName;

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

@ManyToOne
@JoinColumn(name = "user_id", nullable = false)
private User user;






@Autowired
private TaskService taskService;

@GetMapping("/getAllTask")
public List<Task> getAllTasks(){
    return taskService.getAllTask();
}

@CrossOrigin(origins = "http://localhost:3000")
@PostMapping("/addTask")
public void addTask(@RequestBody Task task){
    taskService.addTask(task);
}



@Autowired
private TaskRepo taskRepo;

public List<Task> getAllTask(){
    List<Task> tasks = new ArrayList<>();
    taskRepo.findAll().forEach(task -> tasks.add(task));
    return tasks;
}

public void addTask(Task task){
    taskRepo.save(task);
}







{
        "taskName": "Task 1",
        "description": "This is the first item",
        "user_id": 1
    }



{
    "timestamp": "2019-04-02T02:15:06.989+0000",
    "status": 500,
    "error": "Internal Server Error",
    "message": "could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement",
    "path": "/task/addTask"
}

[enter image description here][1] ERROR 30016 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause

java.sql.SQLIntegrityConstraintViolationException: Column 'user_id' cannot be null

Answer 1

您的json格式不正确。 user_id不是Task的字段。

您的json应该看起来像这样：

{
  "taskName": "Task 1",
  "description": "This is the first item",
  "user": {
    "id": 1
  }
}

user json字段是指

@ManyToOne
@JoinColumn(name = "user_id", nullable = false)
private User user;

由于User是一个对象，因此需要将其表示为JsonObject。

@ManyToOne JPA spring mysql插入错误，列为空

1 个答案: