Java executes shell commands (multiple batches, one step at a time)

illustrate

There are many programs on the Internet that execute commands through java, but only one command can be executed, or all commands can be executed at once.
And what I want is to execute a command, look at the returned result, and then execute the next command. Unfortunately, I have searched the whole network, and there is no feasible method! ! !
No way, find a way to solve it yourself.

Implementation code

Not much nonsense, just go to the code:

Entry class

import core.CmdClient;

public class Main
{
    
    
    public static void main(String[] args)
    {
    
    
        CmdClient client = new CmdClient();
        client.run("cd /");
        client.run("ls");
        client.run("exit");
        System.out.println("主线程结束");
    }
}

Core code class:
Try not to write too complicated here, and cut off the direct interaction of multi-threading. You can modify it according to your needs.

package core;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

public class CmdClient
{
    
    
    // 中文有乱码的可以试着改一下编码格式。
    private static final Charset charset = StandardCharsets.UTF_8;
    // 初始化
    public CmdClient()
    {
    
    
        try
        {
    
    
            /*
              Runtime.getRuntime().exec()方法本质和windows上的运行一样，只能执行一个命令来启动一个程序。
              这里启动的是sh解释器，可以根据需要改成其他shell解释器。适用mac，linux系统。
              对于windows，则是运行C:\Windows\System32\cmd.exe，同时执行的也不是shell命令，而是dos命令。
             */
            Process process = Runtime.getRuntime().exec("/bin/sh");
            // 获取程序的输出流和输入流
            inputStream = process.getInputStream();
            errorStream = process.getErrorStream();
            outputStream = process.getOutputStream();
            /*
              输出数据需要，若执行的命令没有输出结果，就会阻塞读取流的线程。
              为了防止主线程被阻塞，所以声明新的线程专门盯着输出数据。
             */
            new Thread(this::ReadCmdOut).start();
            new Thread(this::ReadCmdError).start();
        }
        catch (IOException e)
        {
    
     throw new RuntimeException("cmd初始化异常", e); }
        System.out.println("控制台初始化完毕");
    }

    private final InputStream inputStream;
    private final InputStream errorStream;
    private final OutputStream outputStream;

    // 运行命令
    public void run(String cmd)
    {
    
    
        try
        {
    
    
        	// 若执行某些命令出现异常，可以尝试更换 \n 为 \r 或 \n\r
            outputStream.write((cmd + "\n").getBytes(charset));
            outputStream.flush();
        }
        catch (Exception e)
        {
    
     throw new RuntimeException("命令执行错误：" + cmd, e); }
    }

    private void ReadCmdOut()
    {
    
    
        try
        {
    
     print(inputStream); }
        catch (Exception e)
        {
    
     throw new RuntimeException("获取输出流异常", e); }
        System.out.println("正常输出流结束");
    }

    private void ReadCmdError()
    {
    
    
        try
        {
    
     print(errorStream); }
        catch (Exception e)
        {
    
     throw new RuntimeException("获取错误流异常", e); }
        System.out.println("异常输出流结束");
    }

    /**
     * 这里直接把数据打印出来了，有其他需求的可以在这里写判来确定下一步来执行什么。
     */
    private void print(InputStream inputStream) throws IOException
    {
    
    
        byte[] bytes = new byte[1024];
        int i;
        while (true)
        {
    
    
            i = inputStream.read(bytes);
            if (i == -1) break;
            System.out.print(new String(bytes, 0, i, charset));
        }
        System.out.println();
    }
}