当我们保存答案时，hibernate异常行被更新或删除异常 [英] hibernate exception row was updated or deleted exception when we save answer

问题描述

例外：

在这里我提供了引发异常的hibernate项目代码。  org.hibernate.StaleObjectStateException：行被另一个事务更新或删除（或未保存的值映射不正确）：
  

当我们调用下面提到的方法
i时，希望使这个线程安全

pre $ public String saveAnswer（String assignmentid，String answerid，String answer）throws Exception {
$ b $ getStudentManager（）。logRequestedAnswer（answerid，answer）;

User user = getUserManager（）。getCurrentUser（）;

HttpSession session = WebContextFactory.get（）。getSession（）;
int practiceElapsedTime = getStudentManager（）。touchPracticeTime（assignmentid，session）;
long practiceUpdateTime =（（Date）session.getAttribute（student_current_practice_last_update））。getTime（）;

StudentAnswer savedAnswer = getStudentManager（）。saveAnswer（user，assignmentid，answerid，answer）;

地图< String，Object> result = new HashMap< String，Object>（）;
result.put（answerid，savedAnswer.getAnswerKey（）。getObjectid（））;
result.put（answer，savedAnswer.getAnswer（））;

//我们将客户端的时间与服务器同步，节省
result.put（practiceElapsedTime，practiceElapsedTime）;
result.put（practiceUpdateTime，practiceUpdateTime）; $（）
$ b if（savedAnswer.getAssignmentStatus（）。isCompleted（））
result.put（progress，savedAnswer.getAssignmentStatus（）。getPercent（））;
else
result.put（progress，savedAnswer.getAssignmentStatus（）。getProgress（））;

StringWriter json = new StringWriter（）;
ObjectMapper mapper = new ObjectMapper（）;
mapper.writeValue（json，result）;
返回json.toString（）;




解决方案

我用hibernate学了两件事。
首先，如果您多次快速保存同一对象，则可能会出现StaleObjectStateException。这是由于桌面上的版本控制。一个简单的解决方案是禁用它。
如果你的表被多个线程访问，你也应该考虑锁定： http://docs.jboss.org/hibernate/orm/4.0/devguide/en-US/html/ch05.html

Here I am Providing the hibernate project code which throws the exception

Exception:

org.hibernate.StaleObjectStateException:Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect):

When we called the method mentioned below i want to make this thread safe

public String saveAnswer(String assignmentid, String answerid, String answer) throws Exception {

        getStudentManager().logRequestedAnswer(answerid, answer);

        User user = getUserManager().getCurrentUser();

        HttpSession session = WebContextFactory.get().getSession();
        int practiceElapsedTime = getStudentManager().touchPracticeTime(assignmentid, session);
        long practiceUpdateTime = ((Date) session.getAttribute("student_current_practice_last_update")).getTime();

        StudentAnswer savedAnswer = getStudentManager().saveAnswer(user, assignmentid, answerid, answer);

        Map<String, Object> result = new HashMap<String, Object>();
        result.put("answerid", savedAnswer.getAnswerKey().getObjectid());
        result.put("answer", savedAnswer.getAnswer());

        //we're synching the client's time with the server on saves
        result.put("practiceElapsedTime", practiceElapsedTime);
        result.put("practiceUpdateTime", practiceUpdateTime);

        if (savedAnswer.getAssignmentStatus().isCompleted())
            result.put("progress", savedAnswer.getAssignmentStatus().getPercent());
        else
            result.put("progress", savedAnswer.getAssignmentStatus().getProgress());

        StringWriter json = new StringWriter();
        ObjectMapper mapper = new ObjectMapper();
        mapper.writeValue(json, result);
        return json.toString();

    }

解决方案

There are two things i learned with hibernate. First, if you save the same object multiple times rapidly you may have a StaleObjectStateException. This is due to versioning on the table. A simple solution is to disable it. You should consider locking too if your table is accessed by multiple threads: http://docs.jboss.org/hibernate/orm/4.0/devguide/en-US/html/ch05.html

这篇关于当我们保存答案时，hibernate异常行被更新或删除异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！