java - 结束卡在 InputStream.read() 循环中的线程

Question

我启动了一个 cmd 应用程序，它通过这个 SyncPipe Runnable 输出到 System.out:

public class SyncPipe implements Runnable {

    private final InputStream is;
    private final OutputStream os;

    public SyncPipe(InputStream is, OutputStream os) {
        this.is = is;
        this.os = os;
    }

    public void run() {
        try {
            final byte[] buffer = new byte[1024];
            for ( int length = 0; ( length = is.read(buffer) ) != -1; )
                os.write(buffer, 0, length);
            System.out.print("stopped");
        } catch ( Exception ex ) { 
            ex.printStackTrace(); 
        }
    }

}

我用 cmd = "C:/bin/read.exe -f D:/test.jpg" 启动 RunIt

private class RunIt implements Runnable {

    public int p;
    public String cmd;

    public RunIt (int p, String cmd) {
        this.p = p;
        this.cmd = cmd;
    }

    public void run() {
        ProcessBuilder pb = new ProcessBuilder("cmd");
        try {
            process = pb.start();
            (new Thread(new SyncPipe(process.getErrorStream(), System.err))).start();
            (new Thread(new SyncPipe(process.getInputStream(), System.out))).start();
            OutputStream out = process.getOutputStream();
            out.write((cmd + "\r\n").getBytes());
            out.flush();
            out.close();

            try {
                process.waitFor();
            } catch ( InterruptedException e ) {
                e.printStackTrace();
            }

            println("Stopped using %d.", p);
        } catch ( IOException ex ) {
            ex.printStackTrace();
        }
    }

}

我现在的问题是:如何让 (new Thread(new SyncPipe(process.getErrorStream(), System.err))) 死掉？给 SyncPipe 一个 boolean 变量 stop，在运行时将其设置为 true，并通过 for ( int length = 0; ( length = is.read(buffer ) ) != -1 && !stop; ) 没有成功。

非常感谢。

---

我最终采用了@Gray 建议的变通方法。现在可以使用了:

public void run() {
    try {
        final byte[] buffer = new byte[1024];
        do
            if ( is.available() > 0 ) {
                int length = is.read(buffer);
                if ( length != -1 )
                    os.write(buffer, 0, length);
                else
                    stop = true;
            }
        while ( !stop );
    } catch ( Exception ex ) { 
        ex.printStackTrace(); 
    }
}

Answer 1

线程会在底层进程退出时读取EOS并退出。您不必自己做任何特别的事情。

编辑 在我看来，通过阅读您对其他答案的评论，您的真正问题在于结束流程。一旦发生这种情况，这些线程就会松开。你在攻击问题的错误一端。