java 处理 IllegalThreadStateException
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Handling the IllegalThreadStateException
提问by augustus hill
import java.io.*;
class Sysexecute
{
public static void main(String args[]) throws IOException,InterruptedException,IllegalThreadStateException
{
Runtime rt= Runtime.getRuntime();
Process p=rt.exec("ls");
System.out.println(p.exitValue());
}
}
i was learning how to execute system commands in java and this error occured. i tried using throws to negate it but was of no use. please explain the reason and solution
我正在学习如何在 Java 中执行系统命令，但发生了此错误。我尝试使用 throws 来否定它，但没有用。请说明原因和解决方法
actual error:-
Exception in thread "main" java.lang.IllegalThreadStateException: process hasn't exited
at java.lang.UNIXProcess.exitValue(UNIXProcess.java:270)
at Sysexecute.main(Sysexecute.java:8)
回答by Sotirios Delimanolis
Invoke Process#waitFor()before trying to get the exit value. This blocks the current thread until the spawned process terminates. If you don't do this, Process#exitValue()throws
Process#waitFor()在尝试获取退出值之前调用。这会阻塞当前线程，直到产生的进程终止。如果你不这样做，Process#exitValue()抛出
IllegalThreadStateException- if the subprocess represented by this
Processobject has not yet terminated
IllegalThreadStateException- 如果此
Process对象表示的子 进程尚未终止
回答by Parthiban
Always use waitFor(long timeout,TimeUnit unit) instead of waitFor(), so that the thread will not be blocked indefinitely.
始终使用waitFor(long timeout,TimeUnit unit) 而不是waitFor()，这样线程就不会被无限阻塞。
