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Java stackoverflow创建对象_Java_Spring - Fatal编程技术网

Java stackoverflow创建对象

Java stackoverflow创建对象,java,spring,Java,Spring,当我创建GET响应时,出现了Stackoveflow错误 应答控制器 @Controller public class TaskViewController { @Autowired private TaskService taskService; @RequestMapping(value = "/task/view", method = RequestMethod.GET) public @ResponseBody AjaxResponseBody

当我创建GET响应时,出现了Stackoveflow错误

应答控制器

@Controller
public class TaskViewController {

    @Autowired
    private TaskService taskService;

    @RequestMapping(value = "/task/view", method = RequestMethod.GET)
    public @ResponseBody
    AjaxResponseBody getTask(@RequestParam String text) {

        int id;
        AjaxResponseBody result = new AjaxResponseBody();
        Task task;
        System.out.println(text);

        try {
            id = Integer.parseInt(text);
        }
        catch (Exception e) {
            result.setMsg("Invalid task number");
            return result;
        }

        task = taskService.findById(id);

        if (task == null){
            result.setMsg("Task not found");
            return result;
        }

        result.setTask(task);
        return result;
    }
}
public class AjaxResponseBody {

    private String msg;
    private Task task;

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Task getTask() {
        return task;
    }

    public void setTask(Task task) {
        this.task = task;
    }
}
他用AjaxResponseBody类作为答案

@Controller
public class TaskViewController {

    @Autowired
    private TaskService taskService;

    @RequestMapping(value = "/task/view", method = RequestMethod.GET)
    public @ResponseBody
    AjaxResponseBody getTask(@RequestParam String text) {

        int id;
        AjaxResponseBody result = new AjaxResponseBody();
        Task task;
        System.out.println(text);

        try {
            id = Integer.parseInt(text);
        }
        catch (Exception e) {
            result.setMsg("Invalid task number");
            return result;
        }

        task = taskService.findById(id);

        if (task == null){
            result.setMsg("Task not found");
            return result;
        }

        result.setTask(task);
        return result;
    }
}
public class AjaxResponseBody {

    private String msg;
    private Task task;

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Task getTask() {
        return task;
    }

    public void setTask(Task task) {
        this.task = task;
    }
}
当这个控制器工作时,我捕捉到

2017-11-24 10:47:10.514 WARN 1448 --- [nio-8080-exec-4] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Infinite recursion (StackOverflowError) (through reference chain: tracker.models.Project_$$_jvstd06_4["user"]->tracker.models.User_$$_jvstd06_5["watched_project"]->tracker.models.Project_$$_jvstd06_4["user"]->tracker.models.User_$$_jvstd06_5["watched_project"]->tracker.models.Project_$$_jvstd06_4["user"]->tracker.models.User_$$_jvstd06_5["watched_project"]->tracker.models.Project_$$_jvstd06_4["user"]->tracker.models.User_$$_jvstd06_5["watched_project"]->
我是如何理解这种情况的,因为模型用户和模型项目彼此有链接。模型用户有一个可选字段“监视的项目”

并且模型项目具有字段,而不是empriy字段“author”:


我怎么能放弃它?或者任何方式?

JSON序列化尝试序列化对象,并且您有循环引用。关于这件事,有很多疑问。如果您使用的是Jackson,那么您可以对
项目中的
对象
用户
用户
项目中的
对象使用注释
@JsonIgnore


您还可以使用
@JsonManagedReference
@JsonBackReference
作为答案。

用户如何与项目建立多对一关系,项目如何与用户建立多对一关系?我认为其中一个应该是一对多