TCP,UDP,java,Socket简单编程实验

编程实现如下内容：

1）  一台客户机从其标准输入（键盘）读取一行字符，并通过其套接字将该行发送到

服务器。

2）  服务器从其连接套接字读取一行字符。

3）  服务器将该行字符转换成大写。

4）  服务器将修改后的行通过其连接套接字再回发给客户机。

5）  客户机从其套接字中读取修改后的行，然后将该行在其标准输出（监视器）上打

印出来。

TCP实验框架：

1、实验内容有三部分构成

一、MyClientPanel.java 实现界面以及与用户的交互还有与其它两部分的交互

二、MyClient.java 实现TCP Socket读的功能

三、MyWriterClient.java 实现TCP Socket写的功能

2、三部分均实现了Runnable接口，可以直接开启单独的线程。

3、MyClient and MyWriterClient 共同继承自MyBaseClient,而MyBaseClient有静态变量，所以可以通过静态变量实现信息的交互。

代码重点解释：

1、while（true）中调用Thread.sleep()，是为了不让CPU的使用率过高

2、客户端新建Socket

socket = new Socket("127.0.0.1", 2001);

服务端新建Socket

serverSocket = new ServerSocket(2001);
socket = serverSocket.accept();

Socket 的两个得到读和写的流的方法

BufferedReader bufferReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

//发送不成功，在这里设置了 为true之后成功了
PrintWriter printWriter = new PrintWriter(socket.getOutputStream(), true);

3、多线程中要发送成功，需要设置上面那个true的参数

实验代码如下：

package com.example.tcp_client;

public class TCPClient {
public TCPClient() {
MyClientPanel myClientPanel = new MyClientPanel();
new Thread(myClientPanel).start();

MyClient myClient = new MyClient();
new Thread(myClient).start();

new Thread(new MyWriterClient()).start();
}
public static void main(String []args) {
new TCPClient();
}
}

package com.example.tcp_client;

import java.net.Socket;

public class MyBaseClient {

/**
* @author adam
*/
static Socket socket;
static String get_info,send_info;

}

package com.example.tcp_client;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;
import java.net.UnknownHostException;

public class MyClient extends MyBaseClient implements Runnable{

public MyClient () {
try {
socket = new Socket("127.0.0.1", 2001);
get_info = "Client init";
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void run() {
// TODO Auto-generated method stub
while (true){
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
getInfo();
}
}
private void getInfo() {
/*if (get_info == null) {
return;
}*/
try {
BufferedReader bufferReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
get_info = bufferReader.readLine();
} catch (IOException e) {
System.out.println("MyClient getinfo() Error!");
return;
// TODO Auto-generated catch block
//e.printStackTrace();
}

}
}

package com.example.tcp_client;

import java.io.IOException;
import java.io.PrintWriter;

public class MyWriterClient extends MyBaseClient implements Runnable{

/**
* @param args
*/

public void run() {
// TODO Auto-generated method stub
while (true) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
sendInfo();
send_info = null;
}
}
private void sendInfo() {
if (send_info == null) {
return;
}
try {
//发送不成功，在这里设置了 为true之后成功了
PrintWriter printWriter = new PrintWriter(socket.getOutputStream(), true);
printWriter.println(send_info);
send_info = "Client: " + send_info + " ";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

package com.example.tcp_client;

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class MyClientPanel extends JFrame implements Runnable, ActionListener{

String sender,getter;
StringBuffer stringBuffer = new StringBuffer();
MyBaseClient myBaseClient = new MyBaseClient();
JPanel jp;
JTextArea jta;
JTextField jtf;
JScrollPane jsp;
JButton jb;

public MyClientPanel() {
jp = new JPanel();
jta = new JTextArea();
jtf = new JTextField();
jsp = new JScrollPane(jta);
jb = new JButton();

jtf.setCaretColor(Color.GREEN);
jtf.setForeground(Color.GREEN);

jta.setEditable(false);
jb.setText("SEND");
jb.setActionCommand("send");
jb.addActionListener(this);

jp.setLayout(new GridLayout(2,1));
jp.add(jtf);
jp.add(jb);

this.setLayout(new GridLayout(2,1));
this.add(jsp);
this.add(jp);

this.setSize(400, 400);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("Client");
}
public void actionPerformed(ActionEvent ae) {
// TODO Auto-generated method stub
if (ae.getActionCommand() == "send") {
//myBaseClient.send_info = jtf.getText();
myBaseClient.send_info = sender;
if (sender == "bye") {
System.exit(0);
}
stringBuffer.append("Client: " + sender + " ");
jta.setText(stringBuffer.toString());
jtf.setText(null);
this.repaint();
}
}

public void run() {
// TODO Auto-generated method stub
while (true) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
sender = this.jtf.getText();
getter = myBaseClient.get_info;
if (myBaseClient.get_info == null) {
continue;
}
if (myBaseClient.get_info != null) {
stringBuffer.append(getter + " ");
jta.setText(stringBuffer.toString());
myBaseClient.get_info = null;
}
this.repaint();
}
}

}

UDP没有实现界面，只是实现了基本功能

UDP实现注意要点

1、UDP不同于TCP（面向连接），它是通过构建数据报文的形式来进行的。

DatagramPacket sendPacket=new DatagramPacket(sendData,sendData.length,IPAddress,9879);

public DatagramPacket(byte[] paramArrayOfByte, int paramInt1, InetAddress paramInetAddress, int paramInt2)；//paramInt2是server端口号

2、服务器新建Socket，DatagramSocket serverSocket = new DatagramSocket(9879);

    客户端新建Socket, DatagramSocket clientSocket=new DatagramSocket();

实验代码：

package com.example.UDPClient;
import java.io.*;
import java.net.*;

public class UDPClient {
public static void main(String argv[]) throws Exception
{
BufferedReader inFromUser=new BufferedReader(
new InputStreamReader(System.in));
DatagramSocket clientSocket=new DatagramSocket();
InetAddress IPAddress=InetAddress.getByName("Agd_PC");
byte[] sendData=new byte[1024];
byte[] receiveData=new byte[1024];
String sentence=inFromUser.readLine();
sendData=sentence.getBytes();
DatagramPacket sendPacket=new DatagramPacket(sendData,sendData.length,IPAddress,9879);
clientSocket.send(sendPacket);
DatagramPacket receivePacket=new DatagramPacket(receiveData,receiveData.length);
clientSocket.receive(receivePacket);
String modifiedSentence=new String(receivePacket.getData());
System.out.println("FROM SERVER: "+modifiedSentence.trim());
clientSocket.close();
}
}

package com.example.UDPServer;
import java.io.*;
import java.net.*;

public class UDPServer {
public static void main(String argv[]) throws Exception
{
DatagramSocket serverSocket = new DatagramSocket(9879);
byte[] sendData=new byte[1024];
byte[] receiveData=new byte[1024];
while(true) {
DatagramPacket receivePacket=new DatagramPacket(receiveData,receiveData.length);
serverSocket.receive(receivePacket);
String sentence=new String(receivePacket.getData());
InetAddress IPAddress=receivePacket.getAddress();
int port=receivePacket.getPort();
String capitalizedSentence=sentence.toUpperCase();
//System.out.println(port);
sendData=capitalizedSentence.getBytes();
DatagramPacket sendPacket=new DatagramPacket(sendData,sendData.length,IPAddress,port);
serverSocket.send(sendPacket);
}
}
}