Java 使用ProcessBuilder向外部进程发送命令

我正在尝试启动一个命令shell并向其发送'dir'命令。但它不起作用。我使用的代码基于这里的SO问题：

由于我看到以下输出，进程被触发。但是，如果我尝试传递任何命令，它不会以输出或其他任何方式响应：

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

---

您正在返回结果的命令提示符中执行命令

cmd.exe

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

这样做怎么样

Process p=Runtime.getRuntime().exec("cmd /c dir"); 

如果您希望您的程序运行在后面并接收值

private ExecutorService execService = Executors.newFixedThreadPool(1);

try {
            execService.submit(new Runnable() {

                @Override
                public void run() {
                    try {
                         //define the task over here ...
                         //eg. String command= "your command";
                         //    Process pr = rt.exec(command);
                        } catch (IOException ex) {}
                }
            });
 } catch (IOException ex) {}

看看这个节目。 有一个主程序，它有一个用于添加两个数字的GUI。 在终端的屏幕后面有另一个正在运行的程序，它执行相同的加法操作。两者同时运行

import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Myapp extends javax.swing.JFrame {
    public Myapp() {
        initComponents();
    }
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        first = new javax.swing.JTextField();
        jLabel189 = new javax.swing.JLabel();
        jLabel183 = new javax.swing.JLabel();
        second = new javax.swing.JTextField();
        jLabel184 = new javax.swing.JLabel();
        sum = new javax.swing.JTextField();
        signbut = new javax.swing.JButton();
        signbut1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        first.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.LOWERED));

        jLabel189.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel189.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel189.setText("First Number");

        jLabel183.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel183.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel183.setText("Second Number");

        second.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.LOWERED));

        jLabel184.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel184.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel184.setText("Sum");

        sum.setBackground(new java.awt.Color(255, 255, 255));
        sum.setEditable(false);
        sum.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.LOWERED));
        sum.setDisabledTextColor(new java.awt.Color(255, 255, 255));

        signbut.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
        signbut.setText("CLEAR");
        signbut.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                signbutActionPerformed(evt);
            }
        });

        signbut1.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
        signbut1.setText("ADD");
        signbut1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                signbut1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(10, 10, 10)
                        .addComponent(jLabel189, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(first, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel183, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(second, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel184, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(sum, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(70, 70, 70)
                        .addComponent(signbut, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(signbut1, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(26, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel189)
                    .addComponent(first, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(12, 12, 12)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel183)
                    .addComponent(second, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(10, 10, 10)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel184)
                    .addComponent(sum, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(signbut)
                    .addComponent(signbut1))
                .addContainerGap(20, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    private void signbutActionPerformed(java.awt.event.ActionEvent evt) {
       sum.setText("");
       first.setText("");
       second.setText("");
    }

    private void signbut1ActionPerformed(java.awt.event.ActionEvent evt) {
      try
      {
       int a=Integer.parseInt(first.getText());
       int b=Integer.parseInt(second.getText());
       int c=a+b;
       sum.setText(""+c);
      }catch(Exception e){
       sum.setText("");
       first.setText("");
       second.setText("");}
    }
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                BackProgram b=new BackProgram();
                b.getBackendWorker();
                new Myapp().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JTextField first;
    private javax.swing.JLabel jLabel183;
    private javax.swing.JLabel jLabel184;
    private javax.swing.JLabel jLabel189;
    private javax.swing.JTextField second;
    private javax.swing.JButton signbut;
    private javax.swing.JButton signbut1;
    private javax.swing.JTextField sum;
    // End of variables declaration
}

class BackProgram
{
   private ExecutorService execService = Executors.newFixedThreadPool(1);
   public void getBackendWorker() {
        try {
            execService.submit(new Runnable() {
                @Override
                public void run() {
                    try {
                          while(true)
                            {
                            try{
                                    System.out.println("(BackProgram Class) Enter two Numbers:");
                                    Scanner s=new Scanner(System.in);
                                    int a=s.nextInt();
                                    int b=s.nextInt();
                                    int c=a+b;
                                    System.out.println("Number Sum is:"+c);
                                }catch(Exception ed){}
                            }
                        } catch (Exception ex) {}
                }
            });
           } catch (Exception ex) {}

    }
}

import java.util.Scanner；
导入java.util.concurrent.ExecutorService；
导入java.util.concurrent.Executors；
公共类Myapp扩展了javax.swing.JFrame{
公共Myapp（）{
初始化组件（）；
}
@抑制警告（“未选中”）
// 
私有组件（）{
first=newjavax.swing.JTextField（）；
jLabel189=newjavax.swing.JLabel（）；
jLabel183=newjavax.swing.JLabel（）；
second=newjavax.swing.JTextField（）；
jLabel184=newjavax.swing.JLabel（）；
sum=newjavax.swing.JTextField（）；
signbut=newjavax.swing.JButton（）；
signbut1=newjavax.swing.JButton（）；
setDefaultCloseOperation（javax.swing.WindowConstants.EXIT_ON_CLOSE）；
setboorder（javax.swing.BorderFactory.createBevelOrder（javax.swing.border.BevelOrder.LOWERED））；
jLabel189.setFont（新的java.awt.Font（“Tahoma”，1，14））；//NOI18N
jLabel189.setHorizontalAlignment（javax.swing.SwingConstants.RIGHT）；
jLabel189.setText（“第一个数字”）；
jLabel183.setFont（新的java.awt.Font（“Tahoma”，1，14））；//NOI18N
jLabel183.setHorizontalAlignment（javax.swing.SwingConstants.RIGHT）；
jLabel183.setText（“第二个数字”）；
setboorder（newjavax.swing.border.SoftBevelOrder（javax.swing.border.BevelOrder.LOWERED））；
jLabel184.setFont（新的java.awt.Font（“Tahoma”，1，14））；//NOI18N
jLabel184.setHorizontalAlignment（javax.swing.SwingConstants.RIGHT）；
jLabel184.setText（“总和”）；
setBackground（新java.awt.Color（255、255、255））；
sum.setEditable（false）；
setboorder（newjavax.swing.border.SoftBevelOrder（javax.swing.border.BevelOrder.LOWERED））；
setDisabledTextColor（新java.awt.Color（255，255，255））；
setFont（新的java.awt.Font（“Tahoma”，1，11））；//NOI18N
signbut.setText（“清除”）；
signbut.addActionListener（新的java.awt.event.ActionListener（）{
public void actionPerformed（java.awt.event.ActionEvent evt）{
已执行的签名（evt）；
}
});
signbut1.setFont（新的java.awt.Font（“Tahoma”，1，11））；//NOI18N
signbut1.setText（“添加”）；
signbut1.addActionListener（新java.awt.event.ActionListener（）{
public void actionPerformed（java.awt.event.ActionEvent evt）{
已执行的SignBut1操作（evt）；
}
});
javax.swing.GroupLayout=newjavax.swing.GroupLayout（getContentPane（））；
getContentPane（）.setLayout（布局）；
layout.setHorizontalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addGap（10,10,10）
.addComponent（jLabel189，javax.swing.GroupLayout.PREFERRED\u SIZE，120，javax.swing.GroupLayout.PREFERRED\u SIZE）
.addGap（10,10,10）
.addComponent（首先，javax.swing.GroupLayout.PREFERRED\u SIZE，120，javax.swing.GroupLayout.PREFERRED\u SIZE））
.addGroup（layout.createSequentialGroup（）
.addComponent（jLabel183，javax.swing.GroupLayout.PREFERRED\u SIZE，130，javax.swing.GroupLayout.PREFERRED\u SIZE）
.addGap（10,10,10）
.addComponent（第二个，javax.swing.GroupLayout.PREFERRED\u SIZE，120，javax.swing.GroupLayout.PREFERRED\u SIZE））
.addGroup（layout.createSequentialGroup（）
.addComponent（jLabel184，javax.swing.GroupLayout.PREFERRED\u SIZE，130，javax.swing.GroupLayout.PREFERRED\u SIZE）
.addGap（10,10,10）
.addComponent（sum，javax.swing.GroupLayout.PREFERRED_SIZE，120，javax.swing.GroupLayout.PREFERRED_SIZE））
.addGroup（layout.createSequentialGroup（）
.addGap（70,70,70）
.addComponent（signbut，javax.swing.GroupLayout.PREFERRED\u SIZE，90，javax.swing.GroupLayout.PREFERRED\u SIZE）
.addGap（10,10,10）
.addComponent（signbut1，javax.swing.GroupLayout.PREFERRED_SIZE，90，javax.swing.GroupLayout.PREFERRED_SIZE）））
.addContainerGap（26，简称最大值））
);
layout.setVerticalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addGap（20,20,20）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（jLabel189）
.addComponent（首先，javax.swing.GroupLayout.PREFERRED\u SIZE，javax.swing.GroupLayout.DEFAULT\u SIZE，javax.swing.GroupLayout.PREFERRED\u SIZE））
.addGap（12,12,12）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（jLabel183）
.addComponent（第二个，javax.swing
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Myapp extends javax.swing.JFrame {
    public Myapp() {
        initComponents();
    }
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        first = new javax.swing.JTextField();
        jLabel189 = new javax.swing.JLabel();
        jLabel183 = new javax.swing.JLabel();
        second = new javax.swing.JTextField();
        jLabel184 = new javax.swing.JLabel();
        sum = new javax.swing.JTextField();
        signbut = new javax.swing.JButton();
        signbut1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        first.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.LOWERED));

        jLabel189.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel189.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel189.setText("First Number");

        jLabel183.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel183.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel183.setText("Second Number");

        second.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.LOWERED));

        jLabel184.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel184.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel184.setText("Sum");

        sum.setBackground(new java.awt.Color(255, 255, 255));
        sum.setEditable(false);
        sum.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.LOWERED));
        sum.setDisabledTextColor(new java.awt.Color(255, 255, 255));

        signbut.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
        signbut.setText("CLEAR");
        signbut.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                signbutActionPerformed(evt);
            }
        });

        signbut1.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
        signbut1.setText("ADD");
        signbut1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                signbut1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(10, 10, 10)
                        .addComponent(jLabel189, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(first, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel183, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(second, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel184, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(sum, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(70, 70, 70)
                        .addComponent(signbut, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(10, 10, 10)
                        .addComponent(signbut1, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(26, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel189)
                    .addComponent(first, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(12, 12, 12)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel183)
                    .addComponent(second, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(10, 10, 10)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel184)
                    .addComponent(sum, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(signbut)
                    .addComponent(signbut1))
                .addContainerGap(20, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    private void signbutActionPerformed(java.awt.event.ActionEvent evt) {
       sum.setText("");
       first.setText("");
       second.setText("");
    }

    private void signbut1ActionPerformed(java.awt.event.ActionEvent evt) {
      try
      {
       int a=Integer.parseInt(first.getText());
       int b=Integer.parseInt(second.getText());
       int c=a+b;
       sum.setText(""+c);
      }catch(Exception e){
       sum.setText("");
       first.setText("");
       second.setText("");}
    }
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                BackProgram b=new BackProgram();
                b.getBackendWorker();
                new Myapp().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JTextField first;
    private javax.swing.JLabel jLabel183;
    private javax.swing.JLabel jLabel184;
    private javax.swing.JLabel jLabel189;
    private javax.swing.JTextField second;
    private javax.swing.JButton signbut;
    private javax.swing.JButton signbut1;
    private javax.swing.JTextField sum;
    // End of variables declaration
}

class BackProgram
{
   private ExecutorService execService = Executors.newFixedThreadPool(1);
   public void getBackendWorker() {
        try {
            execService.submit(new Runnable() {
                @Override
                public void run() {
                    try {
                          while(true)
                            {
                            try{
                                    System.out.println("(BackProgram Class) Enter two Numbers:");
                                    Scanner s=new Scanner(System.in);
                                    int a=s.nextInt();
                                    int b=s.nextInt();
                                    int c=a+b;
                                    System.out.println("Number Sum is:"+c);
                                }catch(Exception ed){}
                            }
                        } catch (Exception ex) {}
                }
            });
           } catch (Exception ex) {}

    }
}