利用java编写网络聊天程序并加密信息

优化了代码后的地址：https://blog.csdn.net/qq_43483251/article/details/125470514?spm=1001.2014.3001.5501

所用知识：javaGUI+网络编程+多线程+信息加密

**原理：**GUI编写基本的图形化界面，利用UDP传输信息，利用多线程同时接收以及发送信息，利用信息加密，加密，密码以及聊天信息。

可能会遇到的问题：

2.javaGUI中的重画方法，repaint只能在原有基础上重绘，并不能清除原来痕迹。因为我使用的Swing默认为轻量级则不执行update，awt组件才是重量级。解决方法：

removeAll（）移除组件，repaint（）刷新面板，再添加组件( add() )，最后重新布局面板( revalidate() )。

3.只有字符串类型的相同变量的哈希值才会相同，因为字符串都存储在同一内存池中，且每定义一个字符串变量会先判断内存池中是否有相同内容的，如果有就不会开辟新的空间，而是直接将变量指向此内容。

4.网络编程中接收的消息被存储进字节数组中，再次拿出来时其实还附带了空余的字节数组空间中的默认值：0，需要对字节数组做判断并只拿取有效的字符串信息。

代码：

登陆界面代码：

package MyNetworkSecurity01;import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.*;public class Land   {//用来当按钮按下后赋值的变量，控制客户端的弹出int i=0;JFrame frame=new JFrame();//设置面板，为了显示标签JPanel panel=new JPanel();//设置账号，密码的标签JLabel land =new JLabel("请登录或者注册！");JLabel accountNumber =new JLabel("账号:");JLabel password=new JLabel("密码:");//设置标签旁的文本框，因为要观察加密情况，所以密码框也使用普通文本框JTextField accountNumber02 = new  JTextField(20);JTextField password02 = new  JTextField(20);//设置登陆和注册按钮!JButton landButton= new JButton("登陆");JButton registerButton = new JButton("注册");//显示登陆成功的标签JLabel label = new JLabel( "登陆成功!");//登陆成功后跳转的按钮JButton Jump=new JButton("继续");//构造方法Land(){//设置界面居中frame.setBounds(Toolkit.getDefaultToolkit().getScreenSize().width/2-200,Toolkit.getDefaultToolkit().getScreenSize().height/2-250,400,500);//设置程序标题frame.setTitle("                      登陆界面");//设置关闭frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);//设置容器Container container=frame.getContentPane();//设置面板的布局panel.setLayout(null);//将面板放入容器container.add(panel);//设置标签位置land.setBounds(100,25,200,50);accountNumber.setBounds(50,75,50,50);password.setBounds(49,150,50,50);//设置字体的样式：行楷，粗体，大小land.setFont(new Font("行楷",Font.BOLD,20));accountNumber.setFont(new Font("行楷",Font.BOLD,20));password.setFont(new Font("行楷",Font.BOLD,20));//将标签放入面板panel.add(land);panel.add(accountNumber);panel.add(password);//设置文本框的位置accountNumber02.setBounds(100,85,200,30);password02.setBounds(99,160,200,30);//将文本框放入面板panel.add(accountNumber02);panel.add(password02);//设置按钮的位置和大小landButton.setBounds(70,300,80,35);registerButton.setBounds(230,300,80,35);//将按钮添加进面板panel.add(landButton);panel.add(registerButton);Button_ button_ = new Button_();//创建按钮点击事件实现类的对象//设置按钮的监听事件//登陆的监听事件landButton.addActionListener(button_);//注册的监听事件registerButton.addActionListener(button_);Jump.addActionListener(new Button_01());//文本框的事件监听//账号框accountNumber02.addActionListener(button_);//密码框password02.addActionListener(button_);frame.setVisible(true);}//用成员内部类实现按钮点击事件class  Button_ implements ActionListener  {@Overridepublic void actionPerformed(ActionEvent e) {//获取账号框的内容String accountNumber_Button = accountNumber02.getText();accountNumber02.setText("");//清空账号框//获取密码框内容String password_Button = (password02.getText());password02.setText("");//清空密码框//确认账号，密码输入不为空if (accountNumber_Button.equals("") || password_Button.equals("")) {JLabel password03 = new JLabel("抱歉，框不能为空！");password03.setForeground(Color.red);//设置字体颜色password03.setBounds(70, 350, 250, 40);password03.setFont(new Font("行楷", Font.BOLD, 20));panel.removeAll();//移除组件panel.repaint();//刷新移除组件后的效果组件//重新添加组件panel.add(land);panel.add(accountNumber);panel.add(password);panel.add(accountNumber02);panel.add(password02);panel.add(landButton);panel.add(registerButton);panel.add(password03);//重新布局面板panel.revalidate();} else {String hashCode_password="";//将接收到的密码转换成字符数组进行倒置//将获取的密码（字符串）变成字符数组char[] hashCode_password01 =password_Button.toCharArray();//倒置字符数组并转换成字符串，如：第一个变为最后一个。for (int length = hashCode_password01.length-1; length >=0; length--) {hashCode_password=hashCode_password+hashCode_password01[length];}//计算密码的字符串形式的哈希值，并重新赋值给hashCode_password（字符串变量）int i = hashCode_password.hashCode();hashCode_password=""+i;//处理登陆和注册问题if (e.getActionCommand().equals("登陆")) {try {TextSend(accountNumber_Button,hashCode_password);} catch (IOException  ioException) {ioException.printStackTrace();}}//设置显示点击按钮后加密后的密码JLabel password03 = new JLabel("加密后的密码是：");password03.setForeground(Color.red);//设置字体颜色password03.setBounds(70, 100, 200, 40);password03.setFont(new Font("行楷", Font.BOLD, 20));JTextField password_text = new JTextField();//用来显示加密后的密码password_text.setBounds(70, 150, 250, 35);password_text.setText(""+hashCode_password);panel.removeAll();//移除组件panel.repaint();//刷新移除组件后的效果组件//重新添加组件panel.add(password03);panel.add(password_text);panel.add(label);panel.add(Jump);//重新布局面板panel.revalidate();}}}class  Button_01 implements ActionListener{@Overridepublic void actionPerformed(ActionEvent e1) {//设置登陆后的跳转按钮点击事件if(e1.getActionCommand().equals("继续")){frame.setVisible(false);//对信息加密解密的类EncryptionAndDecryption ed = new EncryptionAndDecryption();YouClient youClient = new YouClient();//接收Runnable runnable = () -> {//定义自身名字 //定义对方的端口号//建立进程要用的端口DatagramSocket socket = null;try {socket = new DatagramSocket(9100);} catch (SocketException e) {e.printStackTrace();}//  设置一个接收数据的字符串String data;while (true) {//设置一次接收多少的字节byte数据byte[] data_byte = new byte[100];//单位是字节//构造一个 DatagramPacket用于接收长度的数据包 length 。DatagramPacket packet = new DatagramPacket(data_byte, 0, data_byte.length);//接收来自DatagramPacket的数据包try {socket.receive(packet);} catch (IOException e) {e.printStackTrace();}String s3="";//存储接收到的信息char[] s2 = (new String(packet.getData(), 0, packet.getData().length)).toCharArray();for(char s1:s2){if(s1==0)break;s3=s3+s1;}//在界面上显示收到的信息youClient.receive_text01.setText(s3);//解密ed.Decryption(s3);youClient.receive_text02.setText(ed.data02);//获得包裹中的数据data = "服务端：" + " " +ed.data02;if (!data.equals("")) {youClient.str = youClient.str + data + "\n";youClient.ChatBox.setText(youClient.str);}youClient.connect.setText("连接成功！");}};//接收Thread thread = new Thread(runnable);thread.start();}}}public static void main(String[] args)  {new Land();}//用来发送登陆请求并接收回执/或者发送消息public void TextSend(String accountNumber,String password ) throws IOException {//建立端口DatagramSocket socket=new DatagramSocket(9090);//获取本机地址InetAddress inetAddress=InetAddress.getByName("localhost");//设置另一个的端口号int port=5051;//账号和密码的数据String account="账号"+accountNumber+"密码"+password;//发送数据需要的，数据，地址，端口号DatagramPacket packet=new DatagramPacket(account.getBytes(),0,account.getBytes().length,inetAddress,port);//打包发送socket.send(packet);//接收回执//接收数据包byte[] buffer=new byte[1024];//构造一个 DatagramPacket用于接收长度的数据包 length 。DatagramPacket packet1=new DatagramPacket(buffer,0,buffer.length);//接收来自DatagramPacket的数据包socket.receive(packet1);String receive = new String(packet1.getData(), 0, "登陆成功!".getBytes().length);if(receive.equals("登陆成功!")){try {label.setBounds(120,190,250,30);label.setFont(new Font("行楷", Font.BOLD, 30));Jump.setBounds(140,350,100,30);} catch (Exception e) {e.printStackTrace();}}//关闭流socket.close();}
}

服务端代码：

package MyNetworkSecurity01;import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.*;public class MyServer {//用来存储聊天信息static String str="";//用来接收输入框中的信息static String str1="";JFrame frame=new JFrame();//设置最内层面板JPanel panel=new JPanel();//设置panel_text聊天面板的组件JTextArea ChatBox=new JTextArea(20,10);//文本域，聊天记录显示//设置显示对话内容的面板JScrollPane panel_text=new JScrollPane(ChatBox);//设置容器Container container=frame.getContentPane();//panel的组件JTextField connect = new JTextField();//标签JLabel receive01=new JLabel("收到的加密信息:");JLabel receive02=new JLabel("解译后:");JLabel send_out01=new JLabel("想发送的文字:");JLabel send_out02=new JLabel("加密后:");//文本框JTextField receive_text01=new JTextField();JTextField receive_text02=new JTextField();JTextField send_out_text01=new JTextField();JTextField send_out_text02=new JTextField();JTextField ChatText=new JTextField();//聊天输入框JButton inButton=new JButton("发送"); //发送信息按钮public void init(){//设置界面居中frame.setBounds(Toolkit.getDefaultToolkit().getScreenSize().width/2-300,Toolkit.getDefaultToolkit().getScreenSize().height/2-350,600,700);//设置程序标题frame.setTitle("服务端");//设置关闭frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);//设置面板的布局panel.setLayout(null);//设置聊天面板的大小，位置panel_text.setBounds(200,0,380,500);//将面板放入容器container.add(panel);panel.add(panel_text);//设置最内层面板的组件connect.setBounds(20,50,150,30);receive01.setBounds(20,130,180,30);receive01.setFont(new Font("行楷",Font.BOLD,20));receive01.setForeground(Color.red);//设置字体颜色receive_text01.setBounds(20,160,150,30);receive_text01.setFont(new Font("行楷",Font.BOLD,20));receive02.setBounds(20,190,150,30);receive02.setFont(new Font("行楷",Font.BOLD,20));receive02.setForeground(Color.red);receive_text02.setBounds(20,220,150,30);receive_text02.setFont(new Font("行楷",Font.BOLD,20));send_out01.setBounds(20,300,150,30);send_out01.setFont(new Font("行楷",Font.BOLD,20));send_out01.setForeground(Color.blue);//设置字体颜色send_out_text01.setBounds(20,330,150,30);send_out_text01.setFont(new Font("行楷",Font.BOLD,20));send_out02.setBounds(20,360,150,30);send_out02.setFont(new Font("行楷",Font.BOLD,20));send_out02.setForeground(Color.blue);//设置字体颜色send_out_text02.setBounds(20,390,150,30);send_out_text02.setFont(new Font("行楷",Font.BOLD,20));//聊天输入框设置ChatText.setBounds(200,500,300,30);//聊天框的发送按钮inButton.setBounds(500,500,100,30);//聊天域的字体，大小设置ChatBox.setFont(new Font("行楷",Font.BOLD,20));panel.add(connect);panel.add(receive01);panel.add(receive_text01);panel.add(receive02);panel.add(receive_text02);panel.add(send_out01);panel.add(send_out_text01);panel.add(send_out02);panel.add(send_out_text02);panel.add(ChatText);panel.add(inButton);frame.setVisible(true);//发送按钮的监听事件inButton.addActionListener(new InButton());}//成员内部类实现接口且发发送数据class InButton implements ActionListener {@Overridepublic void actionPerformed(ActionEvent e) {//获取聊天输入框的内容str1 = ChatText.getText();ChatText.setText("");str=str+"我: "+str1+"\n";ChatBox.setText(str);//加密前的信息到界面显示send_out_text01.setText(str1);//对信息加密解密的类EncryptionAndDecryption ed = new EncryptionAndDecryption();//加密ed.Encryption(str1);//  将加密后的信息发送到界面显示send_out_text02.setText(ed.data01);try {new UDP_Send(5656, 9100,ed.data01);} catch (IOException ioException) {ioException.printStackTrace();}}}//处理登陆或者注册问题public void landAndRegister() throws IOException {//在本机地址上建立端口，以接收DatagramSocket socket=new DatagramSocket(5051);//接收数据包byte[] buffer=new byte[1024];//构造一个 DatagramPacket用于接收长度的数据包 length 。DatagramPacket packet=new DatagramPacket(buffer,0,buffer.length);//接收来自DatagramPacket的数据包socket.receive(packet);System.out.println("发送的内容："+new String(packet.getData(),0,packet.getData().length));if(packet.getData()!=null){connect.setText("连接成功!");//获取本机地址InetAddress inetAddress= InetAddress.getByName("localhost");int port=9090;//参数：数据(Byte类型)，发送数据的长度，要发给谁DatagramPacket packet1=new DatagramPacket("登陆成功!".getBytes(),0,"登陆成功!".getBytes().length,inetAddress,port);socket.send(packet1);//发送包}//关闭流socket.close();}MyServer( ) throws IOException {init();landAndRegister();}public static void main(String[] args) throws IOException {MyServer myServer = new MyServer();//对信息加密解密的类EncryptionAndDecryption ed = new EncryptionAndDecryption();//接收Runnable runnable = () -> {//定义自身名字 //定义自己的端口号//建立进程要用的端口DatagramSocket socket = null;try {socket = new DatagramSocket(5052);} catch (SocketException e) {e.printStackTrace();}//  设置一个接收数据的字符串String data;while (true) {//设置一次接收多少的字节byte数据byte[] data_byte = new byte[100];//单位是字节//构造一个 DatagramPacket用于接收长度的数据包 length 。DatagramPacket packet = new DatagramPacket(data_byte, 0, data_byte.length);//接收来自DatagramPacket的数据包try {socket.receive(packet);} catch (IOException e) {e.printStackTrace();}//因为接收的信息的字节数组长度很长，除了信息外还有很多无用的默认值为：0//的数据在数组中，需要加以判断，哪些是有用的，如果不进行判断，输出来的信息//会带很长的正方形的小尾巴String s3="";//存储接收到的信息char[] s2 = (new String(packet.getData(), 0, packet.getData().length)).toCharArray();for(char s1:s2){if(s1==0)break;s3=s3+s1;}//在界面上显示收到的信息myServer.receive_text01.setText(s3);//解密ed.Decryption(s3);myServer.receive_text02.setText(ed.data02);//设置显示在文本域中的信息data = "客户端：" + " "+ ed.data02;if (!data.equals("")) {str = str + data + "\n";myServer.ChatBox.setText(str);}}};//接收Thread thread = new Thread(runnable);thread.start();}
}

客户端代码：

package MyNetworkSecurity01;import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;public class YouClient {//用来存储聊天信息static String str="";//用来接收输入框中的信息static String str1="";JFrame frame=new JFrame();//设置最内层面板JPanel panel=new JPanel();//设置panel_text聊天面板的组件JTextArea ChatBox=new JTextArea(20,10);//文本域，聊天记录显示//设置显示对话内容的面板JScrollPane panel_text=new JScrollPane(ChatBox);//设置容器Container container=frame.getContentPane();//panel的组件JTextField connect = new JTextField();//标签JLabel receive01=new JLabel("收到的加密信息:");JLabel receive02=new JLabel("解译后:");JLabel send_out01=new JLabel("想发送的文字:");JLabel send_out02=new JLabel("加密后:");//文本框JTextField receive_text01=new JTextField();JTextField receive_text02=new JTextField();JTextField send_out_text01=new JTextField();JTextField send_out_text02=new JTextField();JTextField ChatText=new JTextField();//聊天输入框JButton inButton=new JButton("发送"); //发送信息按钮public void init(){//设置界面居中frame.setBounds(Toolkit.getDefaultToolkit().getScreenSize().width/2-300,Toolkit.getDefaultToolkit().getScreenSize().height/2-350,600,700);//设置程序标题frame.setTitle("客户端");//设置关闭frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);//设置面板的布局panel.setLayout(null);//设置聊天面板的大小，位置panel_text.setBounds(200,0,380,500);//将面板放入容器container.add(panel);panel.add(panel_text);//设置最内层面板的组件connect.setBounds(20,50,150,30);receive01.setBounds(20,130,180,30);receive01.setFont(new Font("行楷",Font.BOLD,20));receive01.setForeground(Color.red);//设置字体颜色receive_text01.setBounds(20,160,150,30);receive_text01.setFont(new Font("行楷",Font.BOLD,20));receive02.setBounds(20,190,150,30);receive02.setFont(new Font("行楷",Font.BOLD,20));receive02.setForeground(Color.red);receive_text02.setBounds(20,220,150,30);receive_text02.setFont(new Font("行楷",Font.BOLD,20));send_out01.setBounds(20,300,150,30);send_out01.setFont(new Font("行楷",Font.BOLD,20));send_out01.setForeground(Color.blue);//设置字体颜色send_out_text01.setBounds(20,330,150,30);send_out_text01.setFont(new Font("行楷",Font.BOLD,20));send_out02.setBounds(20,360,150,30);send_out02.setFont(new Font("行楷",Font.BOLD,20));send_out02.setForeground(Color.blue);//设置字体颜色send_out_text02.setBounds(20,390,150,30);send_out_text02.setFont(new Font("行楷",Font.BOLD,20));//聊天输入框设置ChatText.setBounds(200,500,300,30);//聊天框的发送按钮inButton.setBounds(500,500,100,30);//聊天域的字体，大小设置ChatBox.setFont(new Font("行楷",Font.BOLD,20));panel.add(connect);panel.add(receive01);panel.add(receive_text01);panel.add(receive02);panel.add(receive_text02);panel.add(send_out01);panel.add(send_out_text01);panel.add(send_out02);panel.add(send_out_text02);panel.add(ChatText);panel.add(inButton);frame.setVisible(true);//发送按钮的监听事件inButton.addActionListener(new InButton());}//成员内部类实现接口且发发送数据class InButton implements ActionListener {@Overridepublic void actionPerformed(ActionEvent e) {//获取聊天输入框的内容str1 = ChatText.getText();send_out_text01.setText(str1);//对信息加密解密的类EncryptionAndDecryption ed = new EncryptionAndDecryption();//加密ed.Encryption(str1);//  将加密后的信息发送到界面显示send_out_text02.setText(ed.data01);ChatText.setText("");str=str+"我: "+str1+"\n";ChatBox.setText(str);try {new UDP_Send(9099, 5052,ed.data01);} catch (IOException ioException) {ioException.printStackTrace();}}}YouClient(){init();}
}

UDP发送代码：

package MyNetworkSecurity01;import java.io.IOException;
import java.net.*;//发送
public class UDP_Send {//定义对方的端口号public int MyPort,YouPort;//建立进程要用的端口DatagramSocket socket=new DatagramSocket(MyPort);//获取本机ipInetAddress inetAddress= InetAddress.getByName("localhost");//要传输的数据private String data;public UDP_Send(int MyPort,int YouPort,String data) throws IOException {this.MyPort=MyPort;this.YouPort=YouPort;this.data=data;if(!this.data.equals("")) {//准备好要发的数据，目的地的ip地址，进程端口号DatagramPacket packet = new DatagramPacket(this.data.getBytes(), 0, this.data.getBytes().length, inetAddress, this.YouPort);//发送try {socket.send(packet);} catch (IOException e) {e.printStackTrace();}socket.close();this.data="";//清空要传输的数据数据}}
}

加密与解密代码：

package MyNetworkSecurity01;import java.util.Random;public class EncryptionAndDecryption {//设置接收最终加密后信息的字符串变量String data01="";//设置接收最终解密后信息的字符串变量String data02="";//加密public  void Encryption(String encryption){data01="";Random r=new Random();//随机取0-10一个数作为偏移量int Offset01 =r.nextInt(10);//将需要加密的字符串变为字符数组,并且将偏移量作为字符数组的第一个数char[] char01=(Offset01+encryption).toCharArray();/*加入在字符数组的每个数中加入偏移量，使之改变为其他数，如：a+3(3为偏移量)=d,这样加密了信息*/for (int i = 0; i < char01.length; i++) {data01=data01+(char) ((int)char01[i]+Offset01);}}//解密public  void Decryption(String decryption){data02="";//将得到的信息变成字符数组char[] char02 = decryption.toCharArray();//获取偏移量int Offset02= ((int)char02[0]-48)/2;//利用循环和偏移量解出信息，并保存在字符数组中for(int i=1;i<char02.length;i++){data02=data02+(char) (char02[i]-Offset02);}}}