将表连接添加到现有项目导致无限递归 [英] Adding table joins to existing project causes infinite recursion

问题描述

我在这个项目上工作：

这就是在应用程序启动时引发致命错误：

  Servlet.service（）对于path []中的servlet [dispatcherServlet]引发异常[Request processing failed;嵌套异常是org.springframework.http.converter.HttpMessageNotWritableException：无法写入JSON：无限递归（StackOverflowError）（通过引用链：sample.todosapp.spring.domain.User [todos]  - > org.hibernate.collection .internal.PersistentSet [0]  - > sample.todosapp.spring.domain.Todo [ 用户]  - > sample.todosapp.spring.domain.User [ 待办事项]  - > org.hibernate.collection。 internal.PersistentSet [0]  - > sample.todosapp.spring.domain.Todo [ 用户]  - > sample.todosapp.spring.domain.User [ 待办事项]  - > org.hibernate.collection.internal .PersistentSet [0]  - > sample.todosapp.spring.domain.Todo [ 用户]  - > sample.todosapp.spring.domain.User [ 待办事项]  - > org.hibernate.collection.internal。 PersistentSet [0]  - > sample.todosapp.spring.domain.Todo [user]  - > sample.todosapp.spring.domain.User [todos] 
  

......

我完全迷失了，我搜索了所有相关的问题和尝试了所有可能的注释变体，但仍然没有luch。我究竟做错了什么？

解决方案

您应该在您的某个属性中使用mappedBy，而不是在两者中定义关系。从HashSet Todo中移除批注@JoinColumn并将 @OneToMany（cascade = CascadeType.ALL）更改为 @OneToMany（mappedBy =user，cascade = CascadeType.ALL）

I work on this project: https://github.com/s1ddok/todosapp

Here you can find all sources for entity etc. What I'm trying to do is to add a connection between TODO and USER. I want that to be a many-to-one relation since one user can have multiple todos, but todos can only have one owner.

I've created a join table in my MySQL database, with foreign keys etc.

Then I added following annotations:

And that is raising fatal error on Application start:

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Infinite recursion (StackOverflowError) (through reference chain: sample.todosapp.spring.domain.User["todos"]->org.hibernate.collection.internal.PersistentSet[0]->sample.todosapp.spring.domain.Todo["user"]->sample.todosapp.spring.domain.User["todos"]->org.hibernate.collection.internal.PersistentSet[0]->sample.todosapp.spring.domain.Todo["user"]->sample.todosapp.spring.domain.User["todos"]->org.hibernate.collection.internal.PersistentSet[0]->sample.todosapp.spring.domain.Todo["user"]->sample.todosapp.spring.domain.User["todos"]->org.hibernate.collection.internal.PersistentSet[0]->sample.todosapp.spring.domain.Todo["user"]->sample.todosapp.spring.domain.User["todos"]

......

I'm completely lost. I search all related questions and tried all possible annotation variants, but still have no luch. What exactly I did wrong?

解决方案

You should use mappedBy in one of your attributes and not define the relationship in both of them. Remove the annotation @JoinColumn from the HashSet Todo and change @OneToMany(cascade = CascadeType.ALL) to @OneToMany(mappedBy = "user" , cascade = CascadeType.ALL)

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