java - commons-exec : hanging when I call executor. 执行(命令行)；

Question

我不知道为什么会挂起。我正在 try catch 通过 commons-exec 运行的进程的输出，但我继续挂起。我在下面提供了一个示例程序来演示此行为。

import java.io.DataInputStream;
import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
import org.apache.commons.exec.PumpStreamHandler;
public class test {

public static void main(String[] args) {
    String command = "java";

    PipedOutputStream output = new PipedOutputStream();
    PumpStreamHandler psh = new PumpStreamHandler(output);

    CommandLine cl = CommandLine.parse(command);

    DefaultExecutor exec = new DefaultExecutor();
    DataInputStream is = null;
    try {
        is = new DataInputStream(new PipedInputStream(output));
        exec.setStreamHandler(psh);
        exec.execute(cl);
    } catch (ExecuteException ex) {
    } catch (IOException ex) {
    }

    System.out.println("huh?");
}
}

Answer 1

根据javadoc , execute(CommandLine command) 是同步的，execute(CommandLine command, ExecuteResultHandler handler) 是异步的。