238 lines
7.0 KiB
Markdown
238 lines
7.0 KiB
Markdown
# 网络编程：
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## 软件架构：
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**BS**
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Browser Server 浏览器 服务端
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**CS**
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Client Server 客户段 服务端
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## 总结：
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229162054898.png" alt="image-20251229162046866" style="zoom: 50%;" />
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## 网络编程三要素
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### **IP**
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229162724636.png" alt="image-20251229162723116" style="zoom:50%;" />
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**特殊ip地址：**
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**常用命令：**
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ipconfig:查看本机ip地址
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ping:检查网络是否畅通
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### **端口**
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229164024494.png" alt="image-20251229164022824" style="zoom:50%;" />
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### 协议
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**UDP协议：不可靠 速度快**
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案例：收发消息：
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接收端：
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```Java
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public class Receive {
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public static void main(String[] args) throws Exception{
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//创建DatagramSocket对象
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DatagramSocket socket = new DatagramSocket(9999);
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//创建DatagramPacket对象
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DatagramPacket packet = new DatagramPacket(new byte[1024],1024);
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//接受信息
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socket.receive(packet);
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//拆包裹
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byte [] data =packet.getData();
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String msg = new String(data);
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String ip = packet.getAddress().getHostAddress();
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System.out.println("从"+ip+"ip发过来的信息："+msg);
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//释放资源
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socket.close();
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}
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}
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```
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发送端：
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```Java
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public class Send {
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public static void main(String[] args) throws Exception{
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//创建DatagramSocket对象
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DatagramSocket socket = new DatagramSocket(8888);
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//准备材料
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String msg ="あんな别吃了";
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byte[] bytes = msg.getBytes();
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//打包包裹
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DatagramPacket packet = new DatagramPacket(bytes,
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bytes.length,
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InetAddress.getByName("127.0.0.1"),//参数为对方的ip对方的端口
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9999);
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socket.send(packet);
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socket.close();
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}
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}
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```
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**TCP协议：可靠信息安全，速度慢**
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229173459039.png" alt="image-20251229173457548" style="zoom:50%;" />
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**三次握手：**
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229184655532.png" alt="image-20251229184654252" style="zoom: 50%;" />
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**四次挥手：**
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<img src="https://gitee.com/icecat2233/picture/raw/master/20251229185455707.png" alt="image-20251229185454457" style="zoom:50%;" />
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大型案例：重点分析：
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TCP上传文件：
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客户端
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```Java
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package com.ice.cat.test;
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import java.io.*;
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import java.lang.reflect.Type;
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import java.net.Socket;
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public class Client {
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public static void main(String[] args) throws Exception {
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Socket socket = new Socket("10.104.117.228",9999);
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//获取输入输出流
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InputStream is = socket.getInputStream();
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OutputStream os = socket.getOutputStream();
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//将字节流转化为字符流，用来处理一些中文字符,再转化为字符缓冲流，可以读取一整行
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BufferedReader br = new BufferedReader(new InputStreamReader(is));
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BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
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//写出文件的名字
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File file = new File("C:\\Users\\asus\\Pictures\\ariya.png");
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bw.write(file.getName());//没带换行符
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bw.newLine();
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bw.flush();
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//接受客户端反馈
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String flag = br.readLine();
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if (flag.equals("ok")){
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//继续上传文件
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//创建本地流，上传图片
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FileInputStream fle = new FileInputStream(file);
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byte [] bys = new byte[1024];
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int lne;
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while ((lne = fle.read(bys)) != -1){
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os.write(bys,0,lne);
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}
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fle.close();
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//重点：给服务端一个结束标记
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socket.shutdownOutput();//通俗理解，写出了一个-1标记
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}
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//读取服务端的返回消息消息
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String result = br.readLine();
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System.out.println(result);
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socket.close();
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}
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}
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```
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服务端：
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```Java
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package com.ice.cat.test;
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import java.io.*;
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import java.net.ServerSocket;
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import java.net.Socket;
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import java.util.UUID;
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import java.util.concurrent.*;
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public class Server {
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public static void main(String[] args) throws Exception {
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//创建线程池
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ThreadPoolExecutor pool = new ThreadPoolExecutor(4,
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6,
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60,
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TimeUnit.SECONDS,
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new ArrayBlockingQueue<>(10),
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Executors.defaultThreadFactory(),
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new ThreadPoolExecutor.AbortPolicy());
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ServerSocket server = new ServerSocket(9999);
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System.out.println("服务端开启，等待客户端连接");
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//响应请求
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//多次响应上传图片，用循环包裹
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while (true) {
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Socket socket = server.accept();
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pool.submit(new SubmitTask(socket));
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}
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}
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}
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```
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线程池代码：为实现多次运行，可在不同线程进行调用
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```Java
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package com.ice.cat.test;
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import java.io.*;
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import java.net.Socket;
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import java.util.UUID;
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public class SubmitTask implements Runnable{
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private Socket socket;
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public SubmitTask(Socket socket){
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this.socket = socket;
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}
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@Override
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public void run() {
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try {
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InputStream is = socket.getInputStream();
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OutputStream os = socket.getOutputStream();
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//将字节流转化为字符流，用来处理一些中文字符,再转化为字符缓冲流，可以读取一整行
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BufferedReader br = new BufferedReader(new InputStreamReader(is));
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BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
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//接受文件名字
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String resultName = br.readLine();
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//给用户端反馈
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bw.write("ok");
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bw.newLine();
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bw.flush();
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//读取客户端上传的文件,注意写出上传的位置
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//为避免文件名字重复使用UUID方法
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File file = new File("C:\\Users\\asus\\Desktop\\JAVA", UUID.randomUUID().toString() + resultName);
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//准备本地的输出流，将网络服务端数据写入到指定位置
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FileOutputStream fos = new FileOutputStream(file);
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//读取网络流数据，写入到本地文件
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int lne;
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byte[] bys = new byte[1024];
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//is为网络输入流，没有关联文件，不可能有-1
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while ((lne = is.read(bys)) != -1) {
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fos.write(bys, 0, lne);
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}
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fos.close();
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//回写给客户段消息
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bw.write("上传成功");
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bw.newLine();
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bw.flush();
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//关流
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socket.close();
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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}
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```
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补充点：若文件名重复则使用UUID.randomUUID().toString()来生成随机名字 |