您需要在子进程的流和 System
流(System.in
、System.out
和 System.err
)之间复制输入和输出。这与我最近的问题相关 (链接)。目前我找到的最佳解决方案是:
import java.io.FileInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousCloseException;
import java.nio.channels.FileChannel;
class StreamCopier implements Runnable {
private InputStream in;
private OutputStream out;
public StreamCopier(InputStream in, OutputStream out) {
this.in = in;
this.out = out;
}
public void run() {
try {
int n;
byte[] buffer = new byte[4096];
while ((n = in.read(buffer)) != -1) {
out.write(buffer, 0, n);
out.flush();
}
}
catch (IOException e) {
System.out.println(e);
}
}
}
class InputCopier implements Runnable {
private FileChannel in;
private OutputStream out;
public InputCopier(FileChannel in, OutputStream out) {
this.in = in;
this.out = out;
}
public void run() {
try {
int n;
ByteBuffer buffer = ByteBuffer.allocate(4096);
while ((n = in.read(buffer)) != -1) {
out.write(buffer.array(), 0, n);
out.flush();
}
out.close();
}
catch (AsynchronousCloseException e) {}
catch (IOException e) {
System.out.println(e);
}
}
}
public class Test {
private static FileChannel getChannel(InputStream in)
throws NoSuchFieldException, IllegalAccessException {
Field f = FilterInputStream.class.getDeclaredField("in");
f.setAccessible(true);
while (in instanceof FilterInputStream)
in = (InputStream)f.get((FilterInputStream)in);
return ((FileInputStream)in).getChannel();
}
public static void main(String[] args)
throws IOException, InterruptedException,
NoSuchFieldException, IllegalAccessException {
Process process = Runtime.getRuntime().exec("sh -i +m");
Thread outThread = new Thread(new StreamCopier(
process.getInputStream(), System.out));
outThread.start();
Thread errThread = new Thread(new StreamCopier(
process.getErrorStream(), System.err));
errThread.start();
Thread inThread = new Thread(new InputCopier(
getChannel(System.in), process.getOutputStream()));
inThread.start();
process.waitFor();
System.in.close();
outThread.join();
errThread.join();
inThread.join();
}
}
这里的难点在于从
System.in
中提取一个通道。如果没有这个通道,当子进程终止时,您将无法中断读取输入的线程。
这种方法有一个严重的缺点:关闭
System.in
后,您将无法再从中读取。我目前使用的解决方法是使用单个输入重定向线程用于所有子进程。