Java进程IO

Question

我正在使用java在linux中启动GNOME终端进程，并将其输入和输出重定向到我的代码。下面是一段代码。

        public static void main(String[] args) throws InterruptedException
    {
        // TODO Auto-generated method stub  /usr/bin/telnet
        try
        {
            String line, commandInput;
            Scanner scan =  new Scanner(new File("/home/Ashutosh/Documents/testfile"));
            ProcessBuilder telnetProcessBuilder = new ProcessBuilder("/bin/bash");///home/Ashutosh/Documents/tempScript");
            telnetProcessBuilder.redirectErrorStream(true);
            Process telnetProcess = telnetProcessBuilder.start();
            //Process telnetProcess = Runtime.getRuntime().exec("xterm");///home/Ashutosh/Documents/tempScript");
            BufferedReader input = new BufferedReader(new InputStreamReader(telnetProcess.getInputStream()));
            BufferedWriter output = new BufferedWriter(new OutputStreamWriter(telnetProcess.getOutputStream()));
            while(scan.hasNext())
            {
                commandInput = scan.nextLine();
                output.write(commandInput);
/*              if(commandInput.trim().equals("exit"))
                {
                    output.write("exit\r");
                }
                else
                {
                    output.write("((" + commandInput + ") && echo --EOF--) || echo --EOF--\r");
                }
*/              output.flush();
                line = input.readLine();
                while(line != null && !line.trim().equals("--EOF--"))
                {
                    System.out.println(line);
                    line = input.readLine();
                }
                if(line == null)
                    break;
            }
/*          Thread.sleep(500);
            output.write("/home/Ashutosh/Documents/testfile\r");
            Thread.sleep(500);
            output.flush();

            while((line = input.readLine())!= null)
                System.out.println(line);
            telnetProcess.destroy();
*/          //String s = input.readLine();
            //System.out.print(s + "\r\n");
            //s = input.readLine();
            //System.out.print(s + "\r\n");
        }

bash脚本的testfile的内容是

#!/bin/bash

ls -l
pwd
date
exit

我还尝试了下面的交互式脚本，它接受用户的输入，我想从java代码中重定向

#! /bin/bash
echo "Input any number form 0-3:"
read num
case $num in
  0) echo "You are useless";;
  1) echo "You are number 1";;
  2) echo "Too suspecious";;
  3) echo "Thats all man, got to go...!";;
  *) echo "Cant't u read english, this is wrong choice";;
esac
read
exit

我的代码止步于input.readLine();。我不确定，但我认为我无法重定向输出流。

output.write(commandInput);

命令执行得很好，但没有在进程重定向输入上写入我想要的内容，这就是它在readLine();挂起的原因。如果有人已经解决了，请让我知道解决方案。通过下面的链接，我试图解决这个问题，但仍然没有成功：

Java Process with Input/Output Stream

谢谢

Ashutosh

Answer 1

嗨，伙计们，很抱歉反应晚了，经过一些试验，我把它弄好了。我只是让进程正常地完成它的进程并退出，而不是强制退出，然后BufferedReader和BufferedWriter将字符串缓冲区保存在内存中，我现在可以在进程退出后读取它，代码为0。

public static void main(String[] args) throws InterruptedException
{
    // TODO Auto-generated method stub
    try
    {
        String line, commandInput;
        ProcessBuilder telnetProcessBuilder = new ProcessBuilder("/bin/bash");
        telnetProcessBuilder.redirectErrorStream(true);
        Process telnetProcess = telnetProcessBuilder.start();
        BufferedReader input = new BufferedReader(new InputStreamReader(telnetProcess.getInputStream()));
        BufferedWriter output = new BufferedWriter(new OutputStreamWriter(telnetProcess.getOutputStream()));
        commandInput = "ls -l\n";
        output.write(commandInput);
        output.flush();
        commandInput = "pwd\n";
        output.write(commandInput);
        output.flush();
        commandInput = "whoami\n";
        output.write(commandInput);
        output.flush();
        commandInput = "exit\n";
        output.write(commandInput);
        output.flush();
        while((line = input.readLine())!= null)
            System.out.println(line);
    }
}

Answer 2

readLine()读取行的内容，末尾不带换行符。

write()只写文本，它不会添加新行。

您可能希望添加write("\n")；或使用PrintStream或PrintWriter。

我想，你的脚本是作为

#!/bin/bashls -lpwddateexit

这是一个没有换行符的注释。

Answer 3

编辑:巨大的错误，没有将命令添加到ProcessBuilder!！

为什么你不把你的脚本作为Linux脚本运行呢？那是,

ProcessBuilder builder = new ProcessBuilder();
LinkedList<String> command = new LinkedList<String>();
command.add("/bin/bash");
command.add("/home/Ashutosh/Documents/testfile");
builder.command(command);

Process myProc = builder.start();

另外，我注意到这个变量被命名为'telnetProcess‘，但是在我能看到的任何地方都没有调用telnet。也许这就是问题所在？

编辑:添加了我对交互式脚本的建议。

ProcessBuilder builder = new ProcessBuilder();
LinkedList<String> command = new LinkedList<String>();
command.add("/bin/bash");
command.add("/path/to/interactiveScript");
builder.command(command);

final Process myProc = builder.start();

// Java input goes to process input.
Thread inputParser = new Thread() {
  public void run() {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(myProc.getOutputStream()));
    String line = "";
    while(line != null) {
      line = br.readLine();
      bw.write(line);
      bw.newLine();
    }
  }
}.start();

// Process output must go to Java output so user can see it!
Thread outputParser = new Thread() {
  public void run() {  
    BufferedReader br = new BufferedReader(new InputStreamReader(myProc.getInputStream()));
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    String line = "";
    while(line != null) {
      line = br.readLine();
      bw.write(line);
      bw.newLine();
    }
  }
}.start();