网络编程及三大协议（TCP + UDP + Http）

￡神魔★判官ぃ 2024-04-20 11:20 80阅读 0赞

## 网络编程及三大协议（TCP + UDP + Http） ##

### 一、网络编程 ###

#### 1.计算机网络 ####

> 是指将地理位置不同的具有独立功能的多台计算机及其外部设备，通过通信线路连接起来，在网络操作系统，网络管理软件及网络通信协议的管理和协调下，实现资源共享和信息传递的计算机系统。

#### 2.网络编程 ####

> 实现多台计算机之间实现数据的共享和传递，网络应用程序主要组成为：  
> 网络编程+IO流+多线程

#### 3.网络编程三要素 ####

> 网络通讯的模型：请求-响应，客户端-服务端
> 
> 三要素：IP地址，端口，协议（数据传输的规则）
> 
> 1.IP地址
> 
> 1.1.IP地址：网络中计算机的唯一标识（IP地址是一个32位的二进制数据，为了方便，将一个字节的二进制转换为一个十进制的数据）
> 
> 1.2.IP地址的组成：网络号段+主机段
> 
> 1.3.1.A类IP地址:第一段号码为网络号码，剩下的三段号码为本地计算机的号码  
> \----可以配置256*256*256台主机
> 
> 1.3.2.B类IP地址:前二段号码为网络号码，剩下的二段号码为本地计算机的号码  
> 1.3.3.C类IP地址:前三段号码为网络号码，剩下的一段号码为本地计算机的号码  
> 1.3.4.特殊地址:  
> 127.0.0.1 回环地址,可用于测试本机的网络是否有问题. ping 127.0.0.1  
> DOS命令 ipconfig:查看本机IP地址
> 
> 补充：  
> A类地址的表示范围为：0.0.0.0~126.255.255.255，默认网络屏蔽为：255.0.0.0；A类地址分配给规模特别大的网络使用。A类网络用第一组数字表示网络本身的地址，后面三组数字作为连接于网络上的主机的地址。分配给具有大量主机（直接个人用户）而局域网络个数较少的大型网络。例如IBM公司的网络。
> 
> B类地址的表示范围为：128.0.0.0~191.255.255.255，默认网络屏蔽为：255.255.0.0；
> 
> C类地址的表示范围为：192.0.0.0~223.255.255.255，默认网络屏蔽为：255.255.255.0；C类地址分配给小型网络，如一般的局域网和校园网，它可连接的主机数量是最少的，采用把所属的用户分为若干的网段进行管理。
> 
> 2.端口号
> 
> 正在运行的程序的标识
> 
> 1.  A:每个网络程序都会至少有一个逻辑端口
> 2.  B:用于标识进程的逻辑地址，不同进程的标识不同
> 3.  C:有效端口：0-65535，其中0-1024系统使用或保留端口。
> 
> a) 80
> 
> b) ftp:23
> 
> c) www.baidu.com:80
> 
> 1.  通过第三方工具可以查看
> 
> 注意：端口与协议有关：TCP和UDP的端口互不相干，同一个协议的端口不能重复，不同协议的可以重复
> 
> TCP:10086
> 
> UDP:10086
> 
> 3.协议
> 
> 通信规则，就是数据的传输规则
> 
> TCP、UDP都是传输层的协议
> 
> TCP建立连接，形成传输数据的通道；在连接中进行大数据量传输；通过三次握手完成连接，是可靠协议；必须建立连接，效率会稍低，例如：打电话
> 
> UDP将数据源和目的封装到数据包中，不需要建立连接；每个数据报的大小在限制在64k；因无连接，是不可靠协议；不需要建立连接，速度快：例如发短信

#### 4.InetAddress – 主机类 ####

import java.net.InetAddress;
    import java.net.UnknownHostException;
    
    public class Test01 {
        
    
    	public static void main(String[] args) throws UnknownHostException {
        
    		
    		//获取到指定域名的服务器IP地址
    //		InetAddress byName = InetAddress.getByName("www.baidu.com");
    //  	System.out.println(byName);//14.215.177.39
    	
    		//获取到指定域名的所有服务器 IPd地址
    //		InetAddress[] allByName = InetAddress.getAllByName("www.baidu.com");
    //		for (InetAddress inetAddress : allByName) {
        
    //			System.out.println(inetAddress);
    //		}
    		
    		//获取到本机的IP地址
    		InetAddress localHost = InetAddress.getLocalHost();
    		System.out.println(localHost);
    	}
    }

### 二、TCP协议 ###

> Scoket也叫套接字，其表示的是IP地址和端口号的组合。
> 
> 网络编程主要就是指Socket编程，网络间的通信其实就是Socket间的通信，数据就通过IO流在两个Scoket间进行传递。

import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.PrintStream;
    import java.net.Socket;
    import java.net.UnknownHostException;
    
    //客户端
    public class Client {
        
    	//注意：关闭流等于关闭Socket
    	public static void main(String[] args) throws UnknownHostException, IOException {
        
    		
    		//武松
    		Socket socket = new Socket("127.0.0.001", 8888);
    		
    		//1.向服务端发送消息
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		ps.println("武松：小二，上好酒好菜！");
    		
    		//4.接收来自服务端的消息
    		BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(), "GBK"));
    		String readLine = br.readLine();
    		System.out.println(readLine);
    		
    		//关闭资源
    		ps.close();
    		br.close();
    		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;
    //服务端
    public class Server {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		//客栈掌柜
    		ServerSocket server = new ServerSocket(8888);
    		
    		System.out.println("等待端连接中...");
    		
    	
    		//店小二
    		//accept()是线程阻塞的方法，客户端和服务端连接成功后才会生成一个Socket对象
    		Socket socket = server.accept();
    		
    		System.out.println("欢迎光临，客人来了~~~");
    		
    		//2.接收来自客户端的消息
    		BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(),"GBK"));
    		String readLine = br.readLine();
    		System.out.println(readLine);
    		
    		//3.向客户端发送消息
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		ps.println("店小二：好的，您请坐！");
    		
    		//关闭资源
    		br.close();
    		ps.close();
    		socket.close();
    		server.close();
    	}
    }

#### 1.TCP案例之 传输文件 ####

import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.Socket;
    import java.net.UnknownHostException;
    
    public class Client {
        
    
    	public static void main(String[] args) throws UnknownHostException, IOException {
        
    		
    		Socket socket = new Socket("127.0.0.002", 6666);
    		
    		//客户端读取源文件，通过Socket提供的输出流向服务端传输数据即可
    		
    		FileInputStream fis = new FileInputStream("测试视频.mp4");
    		OutputStream os = socket.getOutputStream();
    		
    		byte[] b = new byte[1024];
    		int len;
    		while ((len = fis.read(b)) != -1) {
        
    			os.write(b, 0, len);
    		}
    		fis.close();
    		os.close();
    		socket.close();
    	}
    }

import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    public class Server {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		ServerSocket server = new ServerSocket(6666);
    		Socket socket = server.accept();
    		
    		//通过Socket提供过的输入流接收来自客户端的数据，并写入到本地文件中
    		InputStream is = socket.getInputStream();
    		FileOutputStream fos = new FileOutputStream("copy.mp4");
    		
    		byte[] b = new byte[1024];
    		int len;
    		while ((len = is.read(b)) != -1) {
        
    			fos.write(b, 0, len);
    		}
    		
    		is.close();
    		fos.close();
    		socket.close();
    		server.close();
    	}
    }

#### 2.TCP协议 之 一对一聊天 ####

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 Client {
        
    
    	public static void main(String[] args) throws UnknownHostException, IOException {
        
    		
    		Socket socket = new Socket("127.0.0.001", 5555);
    		
    		Scanner scan = new Scanner(System.in);
    		
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(),"GBK"));
    		
    		while (true) {
        
    			
    			ps.println("小小：" + scan.next());
    			
    			String readLine = br.readLine();
    			System.out.println(readLine);
    		}
    		
    	}
    }

#### 3.TCP协议 之 优化一对一聊天 ####

import java.io.IOException;
    import java.io.PrintStream;
    import java.net.Socket;
    import java.net.UnknownHostException;
    import java.util.Scanner;
    
    public class Client {
        
    
    	public static void main(String[] args) throws UnknownHostException, IOException {
        
    		
    		Socket socket = new Socket("127.0.0.1",5010);
    		
    		new ReceiveThread(socket).start();
    		
    		Scanner scan = new Scanner(System.in);
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		
    		while (true) {
        
    			ps.println("刘备：" + scan.next());
    		}
    	}
    }

import java.io.IOException;
    import java.io.PrintStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.Scanner;
    
    public class Server {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		ServerSocket server = new ServerSocket(5010);
    		
    		Socket socket = server.accept();
    		
    		new ReceiveThread(socket).start();
    		
    		Scanner scan = new Scanner(System.in);
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		
    		while (true) {
        
    			ps.println("张飞：" + scan.next());
    		}
    	}
    }

import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.Socket;
    
    public class ReceiveThread extends Thread{
        
    
    	private Socket socket;
    
    	public ReceiveThread(Socket socket) {
        
    		this.socket = socket;
    	}
    	
    	@Override
    	public void run() {
        
    		try {
        
    			BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(), "GBK"));
    			while (true) {
        
    				String readLine = br.readLine();
    				System.out.println(readLine);
    			}
    		} catch (IOException e) {
        
    			e.printStackTrace();
    		}
    	}
    }

#### 4.TCP协议 之 群聊 ####

import java.io.IOException;
    import java.io.PrintStream;
    import java.net.Socket;
    import java.net.UnknownHostException;
    import java.util.Scanner;
    
    public class Client {
        
    
    	public static void main(String[] args) throws UnknownHostException, IOException {
        
    		
    		Socket socket = new Socket("127.0.0.1", 4563);
    		
    		new ReceiveThread(socket).start();
    		
    		Scanner scan = new Scanner(System.in);
    		PrintStream ps = new PrintStream(socket.getOutputStream());
    		while (true) {
        
    			ps.println("关羽：" + scan.next());
    		}
    	}
    }

import java.io.IOException;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.concurrent.ConcurrentHashMap;
    
    public class Server {
        
    
    	public static final ConcurrentHashMap<String, Socket> map = new ConcurrentHashMap<>();
    	
    	public static void main(String[] args) throws IOException {
        
    		
    		ServerSocket server = new ServerSocket(4563);
    		
    		while (true) {
        
    			
    			Socket socket = server.accept();
    			
    			//获取客户端的IP地址
    			String ip = socket.getInetAddress().toString();
    			System.out.println(ip);
    			
    			//将IP地址和Socket对象存入Map中
    			map.put(ip,socket);
    			
    			//此线程 -- 接收当前Socket的消息，并发送给其他Socket
    			 new ServerThread(socket).start();
    		}
    	}
    }

import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.Socket;
    
    public class ReceiveThread extends Thread{
        
    
    	private  Socket socket;
    
    	public ReceiveThread(Socket socket) {
        
    		this.socket = socket;
    	}
    	
    	@Override
    	public void run() {
        
    
    		try {
        
    			BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(),"GBK"));
    			while (true) {
        
    				String readLine = br.readLine();
    				System.out.println(readLine);
    			}
    		} catch (IOException e) {
        
    			e.printStackTrace();
    		}
    	}
    }

import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.PrintStream;
    import java.io.UnsupportedEncodingException;
    import java.net.Socket;
    import java.util.Map.Entry;
    import java.util.Set;
    import java.util.concurrent.ConcurrentHashMap;
    
    public class ServerThread extends Thread{
        
    
    	private Socket socket;
    
    	public ServerThread(Socket socket) {
        
    		this.socket = socket;
    	}
    	
    	@Override
    	public void run() {
        
    		//接收当前Socket的消息，并发送给其他Socket
    		try {
        
    			BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream(),"GBK"));
    			
    			while (true) {
        
    				String readLine = br.readLine();
    				System.out.println(readLine);
    				
    				ConcurrentHashMap<String, Socket> map = Server.map;
    				Set<Entry<String,Socket>> entrySet = map.entrySet();
    				for (Entry<String, Socket> entry : entrySet) {
        
    					String ip = entry.getKey();
    					Socket value = entry.getValue();
    					
    					if (!socket.getInetAddress().toString().equals(ip)) {
        
    						PrintStream ps = new PrintStream(value.getOutputStream());
    						ps.println(readLine);
    					}
    				}
    			}
    		} catch (UnsupportedEncodingException e) {
        
    			e.printStackTrace();
    		} catch (IOException e) {
        
    			e.printStackTrace();
    		}
    		
    	}
    }

### 四、UDP协议 ###

#### 1.简介 ####

> UDP（User Datagram Protocol）用户数据报包协议，UDP和TCP位于同一层-传输层，但它对于数据包的顺序错误或重发没有TCP可靠；UDP是一种面向无连接的通信协议。UDP向应用程序提供一种发送封装的原始IP数据报的方法，并且发送时无需建立连接，不保证可靠数据的传输
> 
> UDP — 发短信
> 
> TCP — 打电话

import java.net.DatagramSocket;
    import java.net.SocketException;
    
    public class Client01 {
        
    
    	public static void main(String[] args) throws SocketException {
        
    		
    		DatagramSocket socket = new DatagramSocket(8808);
    		
    		new ReceiveThread(socket).start();
    		
    		new SendThread(socket, "127.0.0.1", 9099, "马超").start();
    		
    	}
    }

import java.net.DatagramSocket;
    import java.net.SocketException;
    
    public class Client02 {
        
    
    	public static void main(String[] args) throws SocketException {
        
    		
    		DatagramSocket socket = new DatagramSocket(9099);
    		
    		new ReceiveThread(socket).start();
    		new SendThread(socket, "127.0.0.1", 8808, "吕布").start();
    	}
    }

import java.io.IOException;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    public class ReceiveThread extends Thread{
        
    
    	private DatagramSocket socket;
    
    	public ReceiveThread(DatagramSocket socket) {
        
    		this.socket = socket;
    	}
    	
    	@Override
    	public void run() {
        
    
    		while (true) {
        
    		
    			try {
        
    				//数据容器
    				byte[] buf = new byte[1024];
    				//数据报包
    				DatagramPacket dp = new DatagramPacket(buf, 0, buf.length);
    				//接收数据报包
    				socket.receive(dp);
    				//打印
    				System.out.println(new String(buf).trim());
    			} catch (IOException e) {
        
    				e.printStackTrace();
    			}
    		}
    	}
    }

import java.io.IOException;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.UnknownHostException;
    import java.util.Scanner;
    
    public class SendThread extends Thread{
        
    
    	private DatagramSocket socket;
        private String ip;
        private int port;
        private String name;
        
        public SendThread(DatagramSocket socket, String ip, int port, String name) {
        
    		this.socket = socket;
    		this.ip = ip;
    		this.port = port;
    		this.name = name;
    	}
    
    	@Override
        public void run() {
        
    		
    		Scanner scan = new Scanner(System.in);
    		
    		while (true) {
        
    			
    			try {
        
    				//数据
    				byte[] buf = (name + ":" + scan.next()).getBytes();
    				//数据报包
    				DatagramPacket dp = new DatagramPacket(buf, 0, buf.length);
    				//发送数据报包
    				socket.send(dp);
    			} catch (UnknownHostException e) {
        
    				e.printStackTrace();
    			} catch (IOException e) {
        
    				e.printStackTrace();
    			}
    		}
        }
    }

#### 2.TCP VS UDP ####

<table> 
 <thead> 
  <tr> 
   <th align="center"></th> 
   <th align="center">TCP</th> 
   <th align="center">UDP</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="center">是否连接</td> 
   <td align="center">面向连接</td> 
   <td align="center">无面向连接</td> 
  </tr> 
  <tr> 
   <td align="center">传输可靠性</td> 
   <td align="center">可靠</td> 
   <td align="center">不可靠</td> 
  </tr> 
  <tr> 
   <td align="center">应用场合</td> 
   <td align="center">传输大量数据</td> 
   <td align="center">少量数据</td> 
  </tr> 
  <tr> 
   <td align="center">速度</td> 
   <td align="center">慢</td> 
   <td align="center">快</td> 
  </tr> 
 </tbody> 
</table>

### 五、Http协议 ###

#### 1.Http案例之获取来电归属地 ####

import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.URL;
    
    import javax.net.ssl.HttpsURLConnection;
    
    public class Test01 {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		//获取链接地址
    		URL url = new URL("https://cx.shouji.360.cn/phonearea.php?number=15879090133");
    		//获取连接对象
    		HttpsURLConnection huc = (HttpsURLConnection) url.openConnection();
    		
    		//设置参数
    		//设置请求方式
    		huc.setRequestMethod("GET");
    		//允许使用输入流
    		huc.setDoInput(true);
    		//允许使用输出流
    		huc.setDoOutput(true);
    		//设置连接超时时间
    		huc.setConnectTimeout(5000);
    		//设置读取超时时间
    		huc.setReadTimeout(5200);
    		
    		//获取响应状态码
    		int responseCode = huc.getResponseCode();
    		
    		if (responseCode == HttpsURLConnection.HTTP_OK) {
        //响应成功
    			
    			InputStreamReader isr = new InputStreamReader(huc.getInputStream(), "UTF-8");
    			char[] c = new char[1024];
    			int len;
    			while ((len = isr.read(c)) != -1) {
        
    				System.out.println(new String(c, 0, len));
    			}
    			isr.close();
    		}else if(responseCode == HttpsURLConnection.HTTP_NOT_FOUND){
        
    			System.out.println("报错了 --- 页面未找到");
    		}
    	}
    }

#### 2.Http案例之获取快递 ####

import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.URL;
    
    import javax.net.ssl.HttpsURLConnection;
    
    public class test02 {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		//获取地址
    		URL url = new URL("https://www.kuaidi100.com/?type=zhongtong&postid=78624759493002");
    		
    		//获取连接对象
    		HttpsURLConnection huc = (HttpsURLConnection) url.openConnection();
    		
    		//设置参数
    		//设置请求方式
    		huc.setRequestMethod("GET");
    		//允许使用输入流
    		huc.setDoInput(true);
    		//允许使用输出流
    		huc.setDoOutput(true);
    		//设置连接超时时间
    		huc.setConnectTimeout(5200);
    		//设置读取超时时间
    		huc.setReadTimeout(5000);
    		
    		//获取响应状态码
    		int responseCode = huc.getResponseCode();
    		
    		if (responseCode == HttpsURLConnection.HTTP_OK) {
        //响应成功
    			
    			InputStreamReader isr = new InputStreamReader(huc.getInputStream(),"UTF-8");
    			
    			char[] c = new char[1024];
    			int len;
    			while ((len = isr.read(c)) != -1) {
        
    				System.out.println(new String(c, 0, len));
    			}
    			isr.close();
    		} else if(responseCode == HttpsURLConnection.HTTP_NOT_FOUND){
        
    			System.out.println("报错了 --- 页面未找到");
    		}
    	}
    }

#### 3.Http案例之下载图片 ####

import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URL;
    
    import javax.net.ssl.HttpsURLConnection;
    
    public class Test03 {
        
    
    	public static void main(String[] args) throws IOException {
        
    		
    		//获取连接地址
    		URL url = new URL("https://ts1.cn.mm.bing.net/th/id/R-C.f27d775447d9f4ab7c71bbe5f8e38831?rik=4ISLL%2fsQWoSY8g&riu=http%3a%2f%2fimg95.699pic.com%2fphoto%2f40014%2f9369.jpg_wh860.jpg&ehk=S%2bDyu%2bhUKhk%2foLxQ6D7fO350Z%2fkmlDrRz5sM5J1QrCk%3d&risl=&pid=ImgRaw&r=0");
    		
    		//获取连接对象
    		HttpsURLConnection huc = (HttpsURLConnection) url.openConnection();
    		
    		//设置参数
    		//设置请求方式
    		huc.setRequestMethod("GET");
    		//允许使用输入流
    		huc.setDoInput(true);
    		//允许使用输出流
    		huc.setDoOutput(true);
    		//设置连接超时时间
    		huc.setConnectTimeout(5200);
    		//设置读取超时时间
    		huc.setReadTimeout(5000);
    		
    		
    		//获取响应状态码
    		int responseCode = huc.getResponseCode();
    		
    		if (responseCode == HttpsURLConnection.HTTP_OK) {
        
    			
    			InputStream is = huc.getInputStream();
    			FileOutputStream fos = new FileOutputStream("冲击的力量.jpg");
    			
    			byte[] b = new byte[1024];
    			int len;
    			while ((len = is.read(b)) != -1) {
        
    				fos.write(b, 0, len);
    			}
    			is.close();
    			fos.close();
    		}else if (responseCode == HttpsURLConnection.HTTP_NOT_FOUND) {
        
    			System.out.println("报错了 --- 页面未找到");
    		}
    		
    	}
    }