使用会话清楚地取消SwingWorker

时间:2012-10-04 10:24:34

标签: java multithreading swing hibernate swingworker

我有以下情况:

2名有会话的swingworkers从数据库收集数据。现在我要取消第二个swingworker。我做swingworker.cancel(true),在swingworker的done()方法中,我用session.close()关闭会话。

在我完成之后,我认为swingworker有一个sql语句,他正在执行但是他被取消并且会话被关闭所以发生以下执行:

java.lang.NullPointerException
    at org.hibernate.engine.jdbc.internal.proxy.ConnectionProxyHandler.getResourceRegistry(ConnectionProxyHandler.java:104)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.getResourceRegistry(AbstractStatementProxyHandler.java:73)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.wrapIfNecessary(AbstractStatementProxyHandler.java:150)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:123)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
    at $Proxy9.executeQuery(Unknown Source)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1953)
    at org.hibernate.loader.Loader.scroll(Loader.java:2510)
    at org.hibernate.loader.custom.CustomLoader.scroll(CustomLoader.java:337)
    at org.hibernate.internal.SessionImpl.scrollCustomQuery(SessionImpl.java:1760)
    at org.hibernate.internal.AbstractSessionImpl.scroll(AbstractSessionImpl.java:232)
    at org.hibernate.internal.SQLQueryImpl.scroll(SQLQueryImpl.java:182)
    at de.mudisar.dataloader.SecondarySwingWorker.doInBackground(SecondarySwingWorker.java:71)
    at de.mudisar.dataloader.SecondarySwingWorker.doInBackground(SecondarySwingWorker.java:32)
    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at javax.swing.SwingWorker.run(SwingWorker.java:316)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

我该怎么做才能解决问题。如果我取消了swingworker,我希望所有sql操作或其他东西都应该被取消,然后关闭会话。

//编辑:

这是我的swingworker的代码。这个摇摆工作者有自己的会议:

@Override
protected Void doInBackground() throws Exception {

doMappings();

fetchSQL();


}

private void fetchSQL(){

for(String str : map.keySet()){

    //build sql;
    SQLQuery q = sess.createSQLQuery(query).addEntity("ins", ALL_RSC_DATA.class);
    q.setFetchSize(Integer.valueOf(1000));
    q.setReadOnly(true);
    ScrollableResults results = q.scroll(ScrollMode.FORWARD_ONLY);
    while (results.next()) {

        //processing

    }

}

}

这是我的另一个处理用户输入的类的动作(取消swingworker):

public Action cancelPrimarySwingWorker = new AbstractAction() {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Override
    public void actionPerformed(ActionEvent arg0) {
        if(psw != null && !psw.isDone()){
            closeDBConnection(psw.getSession());
            psw.cancel(true);
            psw = null;
            restoreData();
        }
    }
};

有关完整信息,请参阅closeDBConnection()的代码:

@SuppressWarnings("deprecation")
public static void closeDBConnection(Session session) {
    if(session != null){
        try {
            //session.connection().createStatement().execute("SHUTDOWN");
            if(session.isOpen()){
                session.cancelQuery();
                session.clear();
                session.close();
            }
            session = null;
        }
        catch (Exception sqle) {
            logging(sqle);
            System.exit(1);
        }
    }

}

1 个答案:

答案 0 :(得分:1)

public void actionPerformed(ActionEvent arg0) {
    if(psw != null && !psw.isDone()){
        closeDBConnection(psw.getSession());
        psw.cancel(true);
        psw = null;
        restoreData();
    }

这肯定会让我觉得你在读取器线程仍在运行时关闭数据库连接,这可能会导致你所看到的正是这样。您需要对事物进行重组,以便读取器线程响应取消并在finally块中关闭连接本身。