网络编程三要素之IP概述：
每个设备在网络中的唯一标识
每台网络终端在网络中都要一个独立的地址，我们在网络中传输数据就是使用这个地址
ipconfig：查看本机IP
ping：测试连接
本地回路地址：127.0.0.1 255.255.255.255是广播地址
IPv4：4个字节组成，4和0-255、大概42亿，30亿都在北美，亚洲4亿。2011年初已经用尽
IPv6：8组，每组4个16进制数
1a2b:0000:aaaa:0000:0000:0000:aabb:1f2f
1a2b::aaaa:0000:0000:0000:aabb:1f2f
1a2b:0000:aaaa::aabb:1f2f
1a2b:0000:aaaa::0000:aabb:1f2f
1a2b:0000:aaaa:0000::aabb:1f2f
网络编程三要素之端口号概述：
每个程序在设备上的唯一标识
每个网络程序都需要绑定一个端口号，传输数据的时候除了确定发到哪台机器上海要明确发到哪个程序
端口号范围从0-65535
编写网络应用就需要绑定一个端口号，尽量使用1024以上的，1024以下的基本上都被系统程序给占用了
常用端口
mysql：3306
oracle：1521
web：80
tomcat：8080
QQ：4000
feiQ：2425
网络编程三要素协议：
为计算机网络中进行数据交换而建立的规则、标准或约定的集合
UDP
面向无连接，数据不安全，速度快，不区分客户端与服务端
TCP
面向连接（三次握手），数据安全，速度略低。分为客户端和服务端
三次握手：客户端先想服务端发起请求，服务端响应请求，传输数据
UDP传输优化：
接收端Receive
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class Demo1_Receive {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666); //创建socket相当于创建码头
DatagramPacket packet = new DatagramPacket(new byte[1024], 1024); //创建Packet相当于创建集装箱
while(true){
socket.receive(packet); //接货，接收数据
byte[] arr = packet.getData(); //获取数据
int len = packet.getLength(); //获取有效的字节个数
String ip = packet.getAddress().getHostAddress(); //获取IP地址
int port = packet.getPort(); //获取端口号
System.out.println(ip + ":" + new String(arr,0,len));
}
}
}
发送端Send
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Scanner;
public class Demo1_Send {
public static void main(String[] args) throws IOException {
Scanner sc = new Scanner(System.in); //创建键盘录入对象
DatagramSocket socket = new DatagramSocket(); //创建socket相当于创建码头
while(true){
String line = sc.nextLine(); //获取键盘录入的字符串
if ("quit".equals(line)) {
break;
}
DatagramPacket packet = //创建packet相当于集装箱
new DatagramPacket(line.getBytes(), line.getBytes().length,InetAddress.getByName("127.0.0.1"),6666);
socket.send(packet);
}
socket.close();
}
}
UDP传输多线程：
发送和接收在一个窗口完成
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.Scanner;
public class Demo2 {
public static void main(String[] args) {
new Receive().start();
new Send().start();
}
}
class Receive extends Thread{
@Override
public void run() {
try {
DatagramSocket socket = new DatagramSocket(6666); //创建socket相当于创建码头
DatagramPacket packet = new DatagramPacket(new byte[1024], 1024); //创建Packet相当于创建集装箱
while(true){
socket.receive(packet); //接货，接收数据
byte[] arr = packet.getData(); //获取数据
int len = packet.getLength(); //获取有效的字节个数
String ip = packet.getAddress().getHostAddress(); //获取IP地址
int port = packet.getPort(); //获取端口号
System.out.println(ip + ":" + new String(arr,0,len));
}
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
class Send extends Thread{
@Override
public void run() {
try {
Scanner sc = new Scanner(System.in); //创建键盘录入对象
DatagramSocket socket = new DatagramSocket(); //创建socket相当于创建码头
while(true){
String line = sc.nextLine(); //获取键盘录入的字符串
if ("quit".equals(line)) {
break;
}
DatagramPacket packet = //创建packet相当于集装箱
new DatagramPacket(line.getBytes(), line.getBytes().length,InetAddress.getByName("127.0.0.1"),6666);
socket.send(packet);
}
socket.close();
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
UDP聊天图形化界面：
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Panel;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Demo3_GUIChat extends Frame {
public Demo3_GUIChat(){
init();
southPanel();
centerPanel();
event();
}
private void event() {
this.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
private void centerPanel() {
Panel center = new Panel(); //创建中间的Panel
TextArea viewText = new TextArea(); //显示的文本区域
TextArea sendText = new TextArea(5,1); //发送的文本区域
center.setLayout(new BorderLayout()); //设置为边界布局管理器
center.add(sendText, BorderLayout.SOUTH);//发送的文本区域放在南边
center.add(viewText, BorderLayout.CENTER);//显示区域放在中间
viewText.setEditable(false); //设置为不可编辑
viewText.setBackground(Color.WHITE); //这只背景颜色
sendText.setFont(new Font("hhh",Font.PLAIN ,16 ));
viewText.setFont(new Font("hhh",Font.PLAIN ,16 ));
this.add(center,BorderLayout.CENTER);
}
public void southPanel() {
Panel south = new Panel(); //创建南边的Panel
TextField tf = new TextField(15); //创建文本字段存储IP地址
Button send = new Button("发送"); //创建发送按钮
Button log = new Button("记录"); //创建记录按钮
Button clear = new Button("清屏"); //创建清屏按钮
Button shake = new Button("震动"); //创建震动按钮
south.add(tf);
south.add(send);
south.add(log);
south.add(clear);
south.add(shake);
this.add(south,BorderLayout.SOUTH); //将Panel放在Frame的南边
}
public void init() {
this.setLocation(500,50);
this.setSize(400, 600);
this.setVisible(true);
}
public static void main(String[] args) {
new Demo3_GUIChat();
}
}
UDP聊天发送功能
UDP聊天记录功能
UDP聊天清屏功能
UDP聊天振动功能
UDP聊天快捷键和代码优化
UDP聊天生成jar文件
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Panel;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileWriter;
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.text.SimpleDateFormat;
import java.util.Date;
public class Demo3_GUIChat extends Frame {
private TextField tf;
private Button send;
private Button log;
private Button clear;
private Button shake;
private TextArea viewText;
private TextArea sendText;
private DatagramSocket socket;
private BufferedWriter bw;
public Demo3_GUIChat(){
init();
southPanel();
centerPanel();
event();
}
private void event() {
this.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
try {
socket.close();
bw.close();
} catch (IOException e1) {
e1.printStackTrace();
}
System.exit(0);
}
});
send.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
try {
send();
} catch (IOException e1) {
e1.printStackTrace();
}
}
});
log.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
try {
logFile();
} catch (IOException e) {
e.printStackTrace();
}
}
});
clear.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
viewText.setText("");
}
});
shake.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
try {
send(new byte[]{-1},tf.getText());
} catch (IOException e1) {
e1.printStackTrace();
}
}
});
sendText.addKeyListener(new KeyAdapter() {
@Override
public void keyReleased(KeyEvent e) {
//if (e.getKeyCode() == KeyEvent.VK_ENTER && e.isControlDown()) { //isControlDown Ctrl键是否被按下
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
try {
send();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
});
}
private void shake() {
int x = this.getLocation().x; //获取横坐标位置
int y = this.getLocation().y; //获取纵坐标位置
for(int i = 0; i < 10; i++){
try {
this.setLocation(x + 10,y + 10);
Thread.sleep(10);
this.setLocation(x + 10,y - 10);
Thread.sleep(10);
this.setLocation(x + 10,y - 10);
Thread.sleep(10);
this.setLocation(x - 10,y - 10);
Thread.sleep(10);
this.setLocation(x,y);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
private void logFile() throws IOException {
bw.flush(); //刷新缓冲区
FileInputStream fis = new FileInputStream("config.txt");
ByteArrayOutputStream baos = new ByteArrayOutputStream(); //在内存中创建缓冲区
int len;
byte[] arr = new byte[8192];
while((len = fis.read(arr)) != -1){
baos.write(arr,0,len);
}
String str = baos.toString(); //将内存中的内容转换成了字符串
viewText.setText(str);
fis.close();
}
private void send(byte[] arr,String ip) throws IOException{
DatagramPacket packet =
new DatagramPacket(arr,arr.length,InetAddress.getByName(ip),9999);
socket.send(packet); //发送数据
}
private void send() throws IOException {
String message = sendText.getText(); //获取发送区域的内容
String ip = tf.getText(); //获取IP地址
ip = ip.trim().length() == 0 ? "255.255.255.255" : ip;
send(message.getBytes(),ip);
String time = getCurrentTime(); //获取当前时间
String str = time + " 我对" + (ip.equals("255.255.255.255") ? "所有人" : ip) + "说\r\n" +message + "\r\n\r\n";
viewText.append(str); //将信息添加到显示区域中
bw.write(str); //将数据写到数据库中
sendText.setText("");
}
private String getCurrentTime() {
Date d = new Date(); //创建当前日期对象
SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
return sdf.format(d); //将时间格式化
}
private void centerPanel() {
Panel center = new Panel(); //创建中间的Panel
viewText = new TextArea();
sendText = new TextArea(5,1);
center.setLayout(new BorderLayout()); //设置为边界布局管理器
center.add(sendText, BorderLayout.SOUTH);//发送的文本区域放在南边
center.add(viewText, BorderLayout.CENTER);//显示区域放在中间
viewText.setEditable(false); //设置为不可编辑
viewText.setBackground(Color.WHITE); //这只背景颜色
sendText.setFont(new Font("hhh",Font.PLAIN ,20 ));
viewText.setFont(new Font("hhh",Font.PLAIN ,20 ));
this.add(center,BorderLayout.CENTER);
}
public void southPanel() {
Panel south = new Panel(); //创建南边的Panel
tf = new TextField(15);
tf.setText("127.0.0.1");
send = new Button("发送");
log = new Button("记录");
clear = new Button("清屏");
shake = new Button("震动");
south.add(tf);
south.add(send);
south.add(log);
south.add(clear);
south.add(shake);
this.add(south,BorderLayout.SOUTH); //将Panel放在Frame的南边
}
public void init(){
this.setLocation(500,50);
this.setSize(600, 800);
new Receive().start();
try {
socket = new DatagramSocket();
bw = new BufferedWriter(new FileWriter("config.txt",true)); //需要在尾部追加
} catch (Exception e) {
e.printStackTrace();
}
this.setVisible(true);
}
private class Receive extends Thread { //接收和发送需要同时执行，所以定义成多线程的
@Override
public void run() {
try {
DatagramSocket socket = new DatagramSocket(9999);
DatagramPacket packet = new DatagramPacket(new byte[8192], 8192);
while(true){
socket.receive(packet); //接收信息
byte[] arr = packet.getData(); //获取字节数据
int len = packet.getLength(); //获取有效的字节数据
if (arr[0] == -1 && len == 1) { //如果发过来的数组第一个存储的值是-1，并且数组长度是1
shake(); //调用震动方法
continue; //终止本次循环，继续下次循环，因为震动后不需要执行下面的代码
}
String message = new String(arr, 0, len); //转换成字符串
String time = getCurrentTime(); //获取当前时间
String ip = packet.getAddress().getHostAddress(); //获取ip地址
String str = time + " " + ip + "对我说：\r\n" + message + "\r\n\r\n";
viewText.append(str);
bw.write(str);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
new Demo3_GUIChat();
}
}
TCP协议：
1、客户端
创建Socket连接服务端（指定ip地址，端口号）通过ip地址找对应的服务器
调用Socket的getInputStream（）和getOutputStream（）方法获取和服务端相连的IO流
输入流可以读取服务端输出流写出的数据
输出流可以写出数据到服务端的输入流
package com.tcp;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Demo1_Client {
public static void main(String[] args) throws UnknownHostException, IOException {
Socket socket = new Socket("127.0.0.1", 12345);
InputStream is = socket.getInputStream(); //获取客户端输入流
OutputStream os = socket.getOutputStream(); //获取客户端的输出流
byte[] arr = new byte[1024];
int len = is.read(arr); //读取服务器发过来的数据
System.out.println(new String(arr,0,len)); //将数据转换成字符串并打印
os.write("我爱学习".getBytes()); //客户端向服务器写数据
socket.close();
}
}
2、服务端
创建ServerSocket（需要指定端口号）
调用ServerSocket的accept（）方法接收一个客户端请求，得到一个Socket
调用Socket的getInputStream（）和getOutputStream（）方法获取和客户端相连的IO流
输入流可以读取客户端输出流写出的数据
输出流可以写出数据到客户端的输入流
package com.tcp;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Demo1_Server {
public static void main(String[] args) throws IOException {
ServerSocket server = new ServerSocket(12345);
Socket socket = server.accept(); //接受客户端的请求
InputStream is = socket.getInputStream(); //获取客户端输入流
OutputStream os = socket.getOutputStream(); //获取客户端的输出流
os.write("学习爱我".getBytes()); //服务器向客户端写数据
byte[] arr = new byte[1024];
int len = is.read(arr); //读取客户端发过来的数据
System.out.println(new String(arr,0,len)); //将数据转换成字符串并打印
socket.close();
}
}
TCP协议代码优化：
package com.tcp;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Demo2_Client {
public static void main(String[] args) throws UnknownHostException, IOException {
Socket socket = new Socket("127.0.0.1", 12345);
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); //将字节流包装成了字符流
PrintStream ps = new PrintStream(socket.getOutputStream()); //PrintStream中有写出换行的方法
System.out.println(br.readLine());
ps.println("我爱学习");
System.out.println(br.readLine());
ps.println("好好学习，天天向上");
socket.close();
}
}
package com.tcp;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Demo2_Server {
public static void main(String[] args) throws IOException {
ServerSocket server = new ServerSocket(12345);
Socket socket = server.accept(); //接受客户端的请求
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); //将字节流包装成了字符流
PrintStream ps = new PrintStream(socket.getOutputStream()); //PrintStream中有写出换行的方法
ps.println("你爱学习吗？");
System.out.println(br.readLine());
ps.println("真的吗？");
System.out.println(br.readLine());
socket.close();
}
}
服务端是多线程的：
public static void demo2() throws IOException {
ServerSocket server = new ServerSocket(12345);
Socket socket = server.accept(); // 接受客户端的请求
new Thread(){
public void run() {
try {
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); // 将字节流包装成了字符流
PrintStream ps = new PrintStream(socket.getOutputStream()); // PrintStream中有写出换行的方法
ps.println("你爱学习吗？");
System.out.println(br.readLine());
ps.println("真的吗？");
System.out.println(br.readLine());
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
};
}.start();
}
练习1：
客户端向服务端写字符串（键盘录入），服务端（多线程）将字符串反转后写会，客户端再次读取到时反转后的字符串
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;
public class Text1_Client {
/**
* 需求：客户端向服务端写字符串（键盘录入），服务端（多线程）将字符串反转后写会，客户端再次读取到时反转后的字符串
* @throws IOException
* @throws UnknownHostException
*/
public static void main(String[] args) throws UnknownHostException, IOException {
Scanner sc = new Scanner(System.in);
Socket socket = new Socket("127.0.0.1", 54321); //创建客户端，指定IP地址和端口号
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); //获取输入流
PrintStream ps = new PrintStream(socket.getOutputStream()); //获取输出流
ps.println(sc.nextLine()); //将字符串写到服务器去
System.out.println(br.readLine()); //将反转后的结果读出来
socket.close();
}
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Test1_Server {
public static void main(String[] args) throws IOException {
ServerSocket server = new ServerSocket(54321);
System.out.println("服务器启动，绑定54321端口");
while(true){
Socket socket = server.accept(); //接受客户端的请求
new Thread(){ //开启一条线程
public void run() {
try {
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream())); //获取输入流
PrintStream ps = new PrintStream(socket.getOutputStream()); //获取输出流
String line = br.readLine(); //将客户端写过来的数据读取出来
line = new StringBuilder(line).reverse().toString(); //链式编程
ps.println(line); //反转后写回去
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
};
}.start();
}
}
}
练习2：
客户端向服务器上传文件
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;
public class Test2_UpdateClient {
public static void main(String[] args) throws UnknownHostException, IOException {
//1、提示输入要上传的文件路径，验证路径是否存在或是否是文件夹
File file = getFile();
//2、发送文件名到服务端
Socket socket = new Socket("127.0.0.1",12345);
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintStream ps = new PrintStream(socket.getOutputStream());
ps.println(file.getName());
//6、接收结果，如果存在给予提示，程序直接退出
String result = br.readLine(); //读取存在后不存在的结果
if ("存在".equals(result)) {
System.out.println("您上传的文件已存在，请不要重复上传");
socket.close();
return;
}
//7、如果不存在，定义FileInputStream读取文件,写出到网络
FileInputStream fis = new FileInputStream(file);
byte[] arr = new byte[8192];
int len;
while((len = fis.read(arr)) != -1) {
ps.write(arr,0,len);
}
fis.close();
socket.close();
}
private static File getFile() {
Scanner sc = new Scanner(System.in);
System.out.println("请输入一个文件路径：");
while (true) {
String line = sc.nextLine();
File file = new File(line);
if (!file.exists()) {
System.out.println("您录入的文件路径不存在，请重新录入：");
}else if (file.isDirectory()) {
System.out.println("您录入的是文件夹路径，请重新录入一个文件路径：");
}else {
return file;
}
}
}
}
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Test2_UpdateServer {
public static void main(String[] args) throws IOException {
//3、建立多线程的服务器
ServerSocket server = new ServerSocket(12345);
System.out.println("服务器启动，绑定12345端口...");
//4、读取文件名
while (true) {
final Socket socket = server.accept(); //接受请求
new Thread() {
public void run() {
try {
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
PrintStream ps = new PrintStream(socket.getOutputStream());
String fileName = br.readLine();
//5.判断文件是否存在, 将结果发回客户端
File dir = new File("update");
dir.mkdir(); //创建文件夹
File file = new File(dir,fileName); //封装成File对象
if(file.exists()) { //如果服务器已经存在这个文件
ps.println("存在"); //将存在写给客户端
socket.close(); //关闭socket
return;
}else {
ps.println("不存在");
}
//8.定义FileOutputStream, 从网络读取数据, 存储到本地
FileOutputStream fos = new FileOutputStream(file);
byte[] arr = new byte[8192];
int len;
while((len = is.read(arr)) != -1) {
fos.write(arr, 0, len);
}
fos.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();
}
}
}
来源：https://www.cnblogs.com/clqbolg/p/10974866.html