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停止等待算法模拟
实现了两个程序通信的前提下，模拟实现停止等待ARQ协议。
模拟实现：
1.正常数据帧的通信过程
2.错误帧的通信过程
3.数据帧的丢失的通信过程
程序源码及资源下载 http://download.csdn.net/detail/qq_24054661/9802134
package com.stopandwait.test;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
import java.net.*;
import java.security.Timestamp;
import java.util.*;
import java.util.prefs.BackingStoreException;
import javax.swing.*;
public class IServer extends JFrame {
private static long time1;
private static long time2;
private JPanel jp = new JPanel();
private JTextArea jta = new JTextArea();
private JScrollPane jsp = null;
private JButton jb = new JButton("发送");
private JTextField jtf = new JTextField(30);
private ServerSocket server;
private Socket socket;
DataOutputStream dos;
DataInputStream dis;
public IServer() throws IOException
{
Toolkit t = Toolkit.getDefaultToolkit();
Dimension Size =t.getScreenSize();
int width = Size.width;
int height = Size.height;
setLocationByPlatform(true);
jsp = new JScrollPane(jta);
this.setTitle("发送方");
this.setSize(600, 500);
this.setBounds((width - 600) / 2,
(height - 500) / 2, 600,500);
jp.add(jtf);
jp.add(jb);
this.add(jsp, BorderLayout.CENTER);
this.add(jp, BorderLayout.SOUTH);
jta.setCaretPosition(jta.getDocument().getLength());// 设置滚动条自动滚动
this.setVisible(true);
this.setAlwaysOnTop(true);
server = new ServerSocket(9000);
socket= server.accept();
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
dos = new DataOutputStream(socket.getOutputStream());
dis =new DataInputStream(socket.getInputStream());
jb.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
try {
Send();
} catch (InterruptedException | IOException e) {
e.printStackTrace();
}
}
});
}
public static void main(String[] args) throws IOException, InterruptedException
{
new IServer();
}
public void Send() throws InterruptedException, IOException
{
String info = jtf.getText();
jtf.setText("");
char[] Msg = info.toCharArray();
dos.write(Msg.length);
for(int i=0;i<Msg.length;i++)
{
Random random=new java.util.Random(); //实现数据帧错传，以随机数的概率来实现
int result=random.nextInt(21);
if(result>=4)
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Sending...:" + Msg[i]);
} else {
jta.append("\r\nSending...:" + Msg[i]);
}
dos.writeChar(Msg[i]); //发送数据帧
time1 = System.currentTimeMillis(); //设置超时计时器
}
else
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Sending...:" + Msg[i]);
} else {
jta.append("\r\nSending...:" + Msg[i]);
}
dos.writeChar(‘η‘); //发送数据帧
time1 = System.currentTimeMillis(); //设置超时计时器
}
int c = dis.readInt(); //接受客户端确认帧
time2 = System.currentTimeMillis();
long time = time2-time1; //System.out.println("接收所用时间："+time);
if(time<500) //确认帧未超时
{
if(c==i+2) //确认帧正确，传输成功，准备传输下一个帧
{
if(i<Msg.length-1)
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive: ACK" + c);
} else {
jta.append("\r\nReceive: ACK" + c);
}
}
else if(i==Msg.length-1)
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("数据传输成功！");
} else {
jta.append("\r\n"+"数据传输成功！");
jta.setForeground(Color.BLUE);
//jta.setEnabled(false);
}
server.close();
}
}
else if(c==-1) //数据帧被丢弃（接收方不接收）
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive: ACK"+(i+1)+"，重新发送"+(i+1)+"帧");
} else {
jta.append("\r\nReceive: ACK"+(i+1)+"，重新发送"+(i+1)+"帧");
}
i=i-1;
}
}
else //超时，重传
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("确认帧超时，重新发送"+(i+1)+"帧");
} else {
jta.append("\r\n确认帧超时，重新发送"+(i+1)+"帧");
}
i=i-1;
}
}
}
}
package com.stopandwait.test;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
public class IClient extends JFrame {
JPanel jp = new JPanel();
JTextArea jta = new JTextArea();
JScrollPane jsp = null;
public IClient()
{
Toolkit t = Toolkit.getDefaultToolkit();
Dimension Size =t.getScreenSize();
int width = Size.width;
int height = Size.height;
setLocationByPlatform(true);
this.setAlwaysOnTop(true);
jsp = new JScrollPane(jta);
this.setTitle("接收方");
this.add(jp);
this.setSize(500, 400);
this.setBounds((width - 500) / 2,
(height - 400) / 2, 600,500);
this.add(jsp, BorderLayout.CENTER);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setVisible(true);
}
public static void main(String[] args) throws UnknownHostException, IOException, InterruptedException {
new IClient().Receive();
}
public void Receive() throws UnknownHostException, IOException, InterruptedException
{
Socket client = new Socket("localhost",9000);
DataOutputStream dos = new DataOutputStream(client.getOutputStream());
DataInputStream dis =new DataInputStream(client.getInputStream());
int length = dis.read(); //读取接收数据帧的长度
//System.out.println(length); //输出要接受的数据的长度
for(int i=0;i<length;i++)
{
char c = dis.readChar(); //接收数据帧，判断是否正确
if(c!=‘η‘){ //CRC数据帧校验正确
Random ran=new java.util.Random();
int re=ran.nextInt(13);
if(re>=4){ //数据帧正确
if(i<length-1)
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive:" + "成功接收"+(i+1)+"号帧，发送ACK"+(i+2)+"，内容为："+c);
} else {
jta.append("\r\nReceive:" + "成功接收"+(i+1)+"号帧，发送ACK"+(i+2)+"，内容为："+c);
}
dos.writeInt(i+2);
Thread.sleep(100);
}
else
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive:" + "成功接收"+(i+1)+"号帧，发送ACK"+(i+2)+"，内容为："+c);
} else {
jta.append("\r\nReceive:" + "成功接收"+(i+1)+"号帧，发送ACK"+(i+2)+"，内容为："+c);
}
dos.writeInt(i+2); //向发送方返回确认帧
Thread.sleep(100);
}
}
else //数据帧内容错误
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive:" + "数据帧内容不符合顺序，丢弃，发送ACK"+(i+1)+"等待!");
} else {
jta.append("\r\nReceive:" + "数据帧内容不符合顺序，丢弃，发送ACK"+(i+1)+"等待!");
}
Thread.sleep(200);
dos.writeInt(-1);
i=i-1;
}
}
else if(c==‘η‘) //CRC数据帧错误丢弃等待
{
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append("Receive:" + "数据帧错误,丢弃等待!");
} else {
jta.append("\r\nReceive:" + "数据帧错误,丢弃等待!");
}
i=i-1;
Thread.sleep(600);
dos.writeInt(-2);
}
}
if (jta.getText() == null || "".equals(jta.getText())) {
jta.append( "接收信息成功！");
} else {
jta.append("\r\n" + "接收信息成功！");
}
jta.setForeground(Color.RED);
//jta.setEnabled(false);
client.close();
}
}
停止等待算法模拟
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