Java系列講座二：Socket網絡通訊實現聊天軟件項目講解（UDP）

    上一篇咱們講了經過TCP方式實現網絡通訊軟件開發的原理，思路及實現，今天跟你們談談Socket通訊中UDP方式通訊的軟件開發步驟及主要代碼講解，UDP實現方式實現的通訊軟件特色是不分客戶端與服務器端，一個程序既是客戶端與是服務器端，典型軟件是一些局域網的聊天軟件，如飛鴿等軟件。

    UDP方式通訊主要用到了java.net包中的3個類分別是DatagramPacket類，DatagramSocket類與InetAddress類，下面經過實現一個簡易聊天軟件小項目來說解他們的使用方法，代碼以下：

package T16;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.FlowLayout;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.SocketException;

import java.net.UnknownHostException;

import java.util.Date;

import javax.swing.BorderFactory;

import javax.swing.JButton;

import javax.swing.JEditorPane;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.JTextField;

/**

 * UDP通訊的聊天軟件

 * 

 * */

public class UDPChat extends JFrame implements ActionListener{

private JLabel lblPort,lblAddr,lblPort2;

private JTextField txtPort,txtAddr,txtPort2;

private JButton btnConn,btnSend,btnClose;

private JEditorPane txtReceive,txtSend;

public UDPChat(int n){

}

private UDPChat(int n,int m){

}

public UDPChat() {

super("UDP通訊的聊天軟件");

lblPort = new JLabel("本機端口：",JLabel.RIGHT);

lblPort2 = new JLabel("對方端口：",JLabel.RIGHT);

lblAddr = new JLabel("對方地址：",JLabel.RIGHT);

txtPort = new JTextField("8888",5);

txtPort2 = new JTextField("9999",5);

InetAddress ipaddr =null;

try {

ipaddr = InetAddress.getLocalHost();

} catch (UnknownHostException e) {

e.printStackTrace();

}

txtAddr = new JTextField(ipaddr.getHostAddress(),10);

btnConn = new JButton("鏈接(C))");

btnConn.setMnemonic('C');

JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));

topPanel.add(lblPort);

topPanel.add(txtPort);

topPanel.add(lblAddr);

topPanel.add(txtAddr);

topPanel.add(lblPort2);

topPanel.add(txtPort2);

topPanel.add(btnConn);

txtReceive = new JEditorPane();

txtSend = new JEditorPane();

JPanel centerPanel = new JPanel(new GridLayout(2,1,5,10));

centerPanel.add(txtReceive);

txtReceive.setBorder(BorderFactory.createLoweredBevelBorder());

//接收框不能編輯

txtReceive.setEditable(false);

txtSend.setBorder(BorderFactory.createLoweredBevelBorder());

centerPanel.add(txtSend);

btnSend = new JButton("發送(S)");

btnSend.setMnemonic('S');

btnClose = new JButton("退出(X)");

btnClose.setMnemonic('X');

JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));

bottomPanel.add(btnSend);

bottomPanel.add(btnClose);

add(topPanel,BorderLayout.NORTH);

//centerPanel.setBackground(Color.RED);

add(centerPanel,BorderLayout.CENTER);

add(bottomPanel,BorderLayout.SOUTH);

btnConn.addActionListener(this);

btnSend.addActionListener(this);

btnClose.addActionListener(this);

//發送按鈕禁用

btnSend.setEnabled(false);

setSize(600, 400);

setVisible(true);

setLocationRelativeTo(null);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

//建立內部類，實現接收線程

class ReceiveThread extends Thread{

DatagramSocket socket;

public ReceiveThread() {

try{

int port = Integer.parseInt(txtPort.getText().trim());

socket = new DatagramSocket(port);

}catch(Exception e){

e.printStackTrace();

}

}

@Override

public void run() {

byte[] b = new byte[1024];

DatagramPacket packet = new DatagramPacket(b,b.length);

while(true){

try {

//接收數據

socket.receive(packet);

//轉換爲字符串

String str = new String(b,0,packet.getLength());

//顯示在接收框

String content = txtReceive.getText();

content += new Date().toLocaleString()+"\n";

content += str+"\n";

txtReceive.setText(content);

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

public static void main(String[] args) {

//UDPChat chat = new UDPChat();

try {

Class.forName("T16.UDPChat").newInstance();

} catch (InstantiationException e) {

e.printStackTrace();

} catch (IllegalAccessException e) {

e.printStackTrace();

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

}

@Override

public void actionPerformed(ActionEvent e) {

if(e.getSource()==btnConn){

btnConn.setEnabled(false);

btnSend.setEnabled(true);

//啓動線程

new ReceiveThread().start();

}else if(e.getSource()==btnSend){

//發送內容

String str = txtSend.getText().trim();

if(str.equals("")){

JOptionPane.showMessageDialog(this, "請輸入要發送的內容");

return;

}

//把要發送的內容顯示到接收框

String content = txtReceive.getText();

content += new Date().toLocaleString()+"\n";

content += str+"\n";

txtReceive.setText(content);

try {

//設置對方IP地址

InetAddress ip = InetAddress.getByName(txtAddr.getText().trim());

//設置對方的端口

int port = Integer.parseInt(txtPort2.getText().trim());

//建立發送包

byte b[] = str.getBytes();

DatagramPacket p = new DatagramPacket(b,b.length,ip,port);

//建立DatagramSocket發送

DatagramSocket socket = new DatagramSocket();

//發送

socket.send(p);

//清空發送框的內容

txtSend.setText("");

} catch (UnknownHostException e1) {

e1.printStackTrace();

} catch (SocketException e2) {

e2.printStackTrace();

} catch (IOException e3) {

e3.printStackTrace();

}

}else if(e.getSource()==btnClose){

System.exit(0);

}

}

}

該程序必須同啓動2個實例才能實如今局域網聊天，互相設置對方的端口與IP地址便可。

本人從事軟件項目開發20年，2005年開始從事Java工程師系列課程的教學工做，錄製50多門精品視頻課程，包含java基礎，jspweb開發，SSH,SSM，SpringBoot，SpringCloud,人工智能，在線支付等衆多商業項目，每門課程都包含有項目實戰，上課PPT，及完整的源代碼下載，有興趣的朋友能夠看看個人在線課堂，

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