java UDP可靠通信
我想做一个java基于的udp的通信，udp不是面向连接，但是我想自己手工对它进行校验和，可以用crc校验，有谁做过的，给我点帮助吧，谢谢
[解决办法]
这个程序试一试：没有crc校验部分，你得的自己添加
不过你可以模拟crc校验，就是每次发送信息增加某些值，接收信息之前进行确认，再返回（类似TCP连接的三次握手）
我建议做模拟crc之前，先做模拟奇偶校验，主要先熟悉API文档中的Byte类和String类的操作技巧和编码问题
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import java.util.regex.*;;
public class PointToPointUDPChat {
Frame f = new Frame("聊天室");
Label lbRemoteIP = new Label("目标IP");// 对方IP
Label lbRemotePort = new Label("目标端口");
Label lbLocalSendPort = new Label("本地发送端口");
Label lbLocalReceivePort = new Label("本地接收端口");
TextField tfRemoteIP = new TextField(15);// 要发送数据的目标IP
TextField tfRemotePort = new TextField(15);// 要发送数据的目标端口
TextField tfLocalSendPort = new TextField(15);// 使用此端口发送数据
TextField tfLocalReceivePort = new TextField(15);// 使用此端口发送数据
String remoteIP = null;
int remotePort = 0;
int localSendPort = 0;
int localReceivePort = 0;
TextArea allChatContent = new TextArea();
TextField sendChatContent = new TextField(20);
Button connect = new Button("连接");
Button disConnect = new Button("断开");
Button bt = new Button("发送");
Thread receiveThread = null;// 利用start和stop控制是否接收消息
public PointToPointUDPChat() {
initFrame();
}
public static void main(String args[]) {
new PointToPointUDPChat();
}
// 外观布局，添加事件响应
public void initFrame() {// //////
f.setSize(400, 500);// 设置容器的大小
f.setLayout(new BorderLayout());
Panel p = new Panel();
Panel p2 = new Panel();
// 添加组件，布置布局
p.setLayout(new GridLayout(5, 5));
p.add(lbRemoteIP);
p.add(tfRemoteIP);
p.add(lbRemotePort);
p.add(tfRemotePort);
p.add(lbLocalSendPort);
p.add(tfLocalSendPort);
p.add(lbLocalReceivePort);
p.add(tfLocalReceivePort);
p.add(connect);
p.add(disConnect);
f.add("North", p);
connect.addActionListener(new ActionListener() {// 连接按钮事件
public void actionPerformed(ActionEvent e) {
try {
remoteIP = tfRemoteIP.getText();
remotePort = Integer.parseInt(tfRemotePort
.getText());
localSendPort = Integer.parseInt(tfLocalSendPort
.getText());
localReceivePort = Integer
.parseInt(tfLocalReceivePort.getText());
} catch (Exception exception) {
prompt("连接信息不能为空或格式错误");
return;
}
if (!checkIP(remoteIP)) {
prompt("目标IP设置错误");
return;
}
if (!checkPort(remotePort)) {
prompt("目标端口设置错误");
return;
}
if (!checkPort(localSendPort)) {
prompt("本地发送端口设置错误");
return;
}
if (!checkPort(localReceivePort)) {
prompt("本地接收端口设置错误");
return;
}
prompt("连接成功");
tfRemoteIP.setEditable(false);
tfRemotePort.setEditable(false);
tfLocalReceivePort.setEditable(false);
tfLocalSendPort.setEditable(false);
receiveMessage();
}
});
disConnect.addActionListener(new ActionListener() {// 断开按钮事件
public void actionPerformed(ActionEvent e) {
tfRemoteIP.setEditable(true);
tfRemotePort.setEditable(true);
tfLocalReceivePort.setEditable(true);
tfLocalSendPort.setEditable(true);
tfLocalReceivePort.setText("");
tfLocalSendPort.setText("");
tfRemoteIP.setText("");
tfRemotePort.setText("");
remoteIP = null;
remotePort = 0;
localSendPort = 0;
localReceivePort = 0;
receiveThread.stop();
prompt("断开成功");
}
});
f.add("Center", allChatContent);
p2.setLayout(new FlowLayout());
p2.add(bt);
p2.add(sendChatContent);// ///p2面板添加发送按钮和要发送的内容
f.add("South", p2);
f.setVisible(true);// 让容器可显示
f.setResizable(false);// 不可改变容器大小
// 关闭窗口事件
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
f.setVisible(false);
f.dispose();
System.exit(0);
}
});
// //////触发发送按钮事件
bt.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sendMessage();
}
});
// 模态显示按钮的触发事件
// 输入文本框的触发事件
sendChatContent.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sendMessage();
}
});
}
// 发送数据
public void sendMessage() {//
// 定义ds
DatagramSocket ds = null;
try {
ds = new DatagramSocket(localSendPort);
} catch (SocketException e1) {
prompt("本地发送端口已被使用");
return;
}
// 设置发送信息
String sendMessage = sendChatContent.getText().trim();
if (sendMessage.equals("")) {
prompt("无效信息");
return;
}
byte[] buf = sendMessage.getBytes();// /////获得要发送的数据
// 设置接收数据的远程IP地址
InetAddress inetAddress = null;
try {
inetAddress = InetAddress.getByName(tfRemoteIP.getText().trim());
} catch (UnknownHostException e) {
prompt("非法远程IP地址");
return;
}
// 发送
DatagramPacket dp = new DatagramPacket(buf, 0, buf.length, inetAddress,
remotePort);
try {
ds.send(dp);
} catch (IOException e) {
prompt("网络故障，发送失败");
return;
}
sendChatContent.setText("");// //发送完数据，发送框重置为空
allChatContent.append(new java.text.SimpleDateFormat(
"yy-MM-dd HH:mm:ss").format(new Date())
+ " send to Remote("
+ dp.getAddress()
+ " "
+ dp.getPort()
+ ") :\n");
allChatContent.append(sendMessage + "\n");
ds.close();
}
// 接收数据
class MyRunnable implements Runnable {
byte buf[] = new byte[1024];
DatagramSocket ds = null;
DatagramPacket dp = null;
public void run() {
dp = new DatagramPacket(buf, 0, 1024);
try {
ds = new DatagramSocket(localReceivePort);
} catch (SocketException e1) {
prompt("本地接收端口已被使用");
return;
}
while (true) {
try {
ds.receive(dp);
} catch (IOException e) {
ds.close();
e.printStackTrace();
}
String receiveMessage = new String(dp.getData(), 0, dp
.getLength());
allChatContent.append(new java.text.SimpleDateFormat(
"yy-MM-dd HH:mm:ss").format(new Date())//
+ " from remote("
+ dp.getAddress().getHostAddress()
+ " " + dp.getPort() + ") :\n" + receiveMessage + "\n");
sendChatContent.setCaretPosition(sendChatContent.getText()
.length());
}
}
}
public void receiveMessage() {//
receiveThread = new Thread(new MyRunnable());
receiveThread.start();
}
// 异常处理
public void prompt(String promptMessage) {
JOptionPane.showConfirmDialog(null, promptMessage, "友情提示",
JOptionPane.WARNING_MESSAGE);
}
public boolean checkPort(int port) {
return String.valueOf(port).matches("\\d+") && port > 1024
&& port <= 65535;
}
public boolean checkPort(String port) {
return port.matches("\\d+") && Integer.parseInt(port) > 1024
&& Integer.parseInt(port) <= 65535;
}
public static boolean isDigit(String text) {
return text.matches("\\d+");
}
public boolean checkIP(String ip) {
java.util.regex.Matcher m = Pattern.compile(
"(\\d{1,3}).(\\d{1,3}).(\\d{1,3}).(\\d{1,3})").matcher(ip);
if (m.find()) {
for (int i = 1; i <= 4; i++)
if (Integer.parseInt(m.group(i)) < 0
[解决办法]
Integer.parseInt(m.group(i)) > 255)
return false;
return true;
}
return true;
}
}