问题描述
public class Actualizacion extends SwingWorker<Void,String>{
private final String cmd;
private final JTextArea jTextArea1;
public Actualizacion (String c,JTextArea j){
cmd = c;
jTextArea1 = j;
}
@Override
protected Void doInBackground() throws Exception {
Process powerShellProcess = Runtime.getRuntime().exec(cmd);
// Getting the results
powerShellProcess.getoutputStream().close();
String line;
BufferedReader stdout = new BufferedReader(new InputStreamReader(
powerShellProcess.getInputStream()));
while ((line = stdout.readLine()) != null) {
publish(line + "\n");
//System.out.println("" + line);
}
stdout.close();
BufferedReader stderr = new BufferedReader(new InputStreamReader(
powerShellProcess.getErrorStream()));
while ((line = stderr.readLine()) != null) {
publish(line + "\n");
//System.out.println("" + line);
}
stderr.close();
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods,choose Tools | Templates.
}
@Override
protected void done(){
publish("\nDone");
try {
get();
} catch (InterruptedException | ExecutionException e) {
e.printstacktrace();
}
}
@Override
protected void process(List<String> lines){
lines.forEach((String line) -> {
jTextArea1.append(line);
});
}
}
这是我的 SwingWorker 类，它应该使用命令“cmd”的输出实时更新 jTextArea，所以正如我所说，输出应该实时写入，但它发生在命令执行结束时，并且我也有例外。
我已经阅读了很多关于线程以及 Java Swing 如何拥有 EventdispatchThread 的内容，但我被卡住了。
这是程序执行的输出：
run:
java.util.concurrent.ExecutionException: java.lang.UnsupportedOperationException: Not supported yet.
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:192)
at javax.swing.SwingWorker.get(SwingWorker.java:602)
at destreamer.Actualizacion.done(Actualizacion.java:66)
at javax.swing.SwingWorker$5.run(SwingWorker.java:737)
at javax.swing.SwingWorker$DoSubmitaccumulativeRunnable.run(SwingWorker.java:832)
at sun.swing.AccumulativeRunnable.run(AccumulativeRunnable.java:112)
at javax.swing.SwingWorker$DoSubmitaccumulativeRunnable.actionPerformed(SwingWorker.java:842)
at javax.swing.Timer.fireActionPerformed(Timer.java:313)
at javax.swing.Timer$DoPostEvent.run(Timer.java:245)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventdispatchThread.pumpOneEventForFilters(EventdispatchThread.java:205)
at java.awt.EventdispatchThread.pumpEventsForFilter(EventdispatchThread.java:116)
at java.awt.EventdispatchThread.pumpEventsForHierarchy(EventdispatchThread.java:105)
at java.awt.EventdispatchThread.pumpEvents(EventdispatchThread.java:101)
at java.awt.EventdispatchThread.pumpEvents(EventdispatchThread.java:93)
at java.awt.EventdispatchThread.run(EventdispatchThread.java:82)
Caused by: java.lang.UnsupportedOperationException: Not supported yet.
at destreamer.Actualizacion.doInBackground(Actualizacion.java:57)
at destreamer.Actualizacion.doInBackground(Actualizacion.java:22)
at javax.swing.SwingWorker$1.call(SwingWorker.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at javax.swing.SwingWorker.run(SwingWorker.java:334)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
非常感谢！
解决方法
这是我的问题的解决方案：
首先我将 Runtime.getRuntime().exec 改为 ProcessBuilder。
然后我意识到我在 UI 中执行了一个可怕的循环，所以这就是 Swing Worker 线程在 EventDispatchThread 之后执行的主要原因。
不要在 UI 人员中使用疯狂循环，在我的情况下是：
while (!file.exist()){
}
我知道这个错误可能是一个基本错误，但我希望这篇文章能在未来对你有所帮助。
感谢@MadProgrammer 和@camickr 这么快就给我答复。