Java Socket

1. 网络基础知识

2. InetAddress 类

InetAddressaddress =InetAddress.getLocalHost();System.out.println(address.getHostName());System.out.println(address.getHostAddress());System.out.println(Arrays.toString(address.getAddress()));System.out.println(address);

3. URL

try {URLurl =newURL("https://www.baidu.com");InputStreamis =url.openStream();InputStreamReaderisr =newInputStreamReader(is,StandardCharsets.UTF_8);BufferedReaderbr =newBufferedReader(isr);Stringdata =br.readLine();while (data !=null) {System.out.println(data);data =br.readLine();    }br.close();isr.close();is.close();}catch (IOExceptione) {e.printStackTrace();}

4. Socket

4.1. 基于 TCP 的 Socket 通信

4.1.1. 服务端

// 1. 创建 ServerSocket 对象，绑定监听端口ServerSocketserverSocket =newServerSocket(8888);System.out.println("***服务器已经启动，开始侦听客户端的连接***");// 2. 通过 accept() 方法监听客户端请求Socketsocket =serverSocket.accept();// 3. 连接建立后，通过输入流读取客户端发送的请求信息InputStreamis =socket.getInputStream();InputStreamReaderisr =newInputStreamReader(is);BufferedReaderbr =newBufferedReader(isr);Stringinfo =null;while ((info =br.readLine()) !=null) {System.out.println("我是服务器，客户端说：" +info);}socket.shutdownInput();// 关闭输入流// 4. 通过输出流向客户端发送响应信息OutputStreamos =socket.getOutputStream();PrintWriterpw =newPrintWriter(os);pw.write("欢迎你");pw.flush();// 5. 关闭相应资源pw.close();os.close();br.close();isr.close();is.close();socket.close();serverSocket.close();

4.1.2. 客户端

// 1. 创建 Socket 对象，指明需要连接的服务器的地址和端口号Socketsocket =newSocket("127.0.0.1",8888);// 2. 连接建立后，通过输出流向服务器发送请求信息OutputStreamos =socket.getOutputStream();PrintWriterpw =newPrintWriter(os);pw.write("user:zhangsan;passwd:123456");pw.flush();socket.shutdownOutput();// 关闭输出流// 3. 通过输入流获取服务器响应的信息InputStreamis =socket.getInputStream();InputStreamReaderisr =newInputStreamReader(is);BufferedReaderbr =newBufferedReader(isr);Stringresp =null;while ((resp =br.readLine()) !=null) {System.out.println("我是客户端，服务器说：" +resp);}socket.shutdownInput();// 关闭输入流// 4. 关闭相应资源pw.close();os.close();br.close();isr.close();is.close();socket.close();

4.2. 使用多线程实现服务端与多客户端通信

// 1. 创建 ServerSocket 对象，绑定监听端口ServerSocketserverSocket =newServerSocket(8888);System.out.println("***服务器已经启动，开始侦听客户端的连接***");intcount =0;// 2. 通过 accept() 方法监听客户端请求Socketsocket;while (true) {socket =serverSocket.accept();ServerThreadthread =newServerThread(socket);thread.setPriority(4);thread.start();count++;System.out.println("客户端的数量为：" +count);InetAddressaddress =socket.getInetAddress();System.out.println("当前客户端的地址为：" +address.getHostAddress());}

5. UDP 编程

5.1. 基于 UDP 的 Socket 通信

5.1.1. 服务端

// 1. 创建 DatagramSocket，指定端口号DatagramSocketsocket =newDatagramSocket(8888);// 2. 创建 DatagramPacketbyte[]data =newbyte[1024];DatagramPacketpacket =newDatagramPacket(data,data.length);System.out.println("***服务器已经启动，开始侦听客户端的连接***");// 3. 接受客户端发送的数据信息// 此方法在接收到数据之前按一直会保持阻塞socket.receive(packet);// 4. 读取数据Stringinfo =newString(data,0,packet.getLength());System.out.println("我是服务器，客户端说：" +info);// 服务器向客户端进行响应InetAddressaddress =packet.getAddress();intport =packet.getPort();byte[]resp ="你好，这是服务器对客户端的响应".getBytes();DatagramPacketrespPacket =newDatagramPacket(resp,resp.length,address,port);socket.send(respPacket);socket.close();

5.1.2. 客户端

// 1. 定义发送信息InetAddressaddress =InetAddress.getLocalHost();intport =8888;byte[]data ="user:zhangsan;passwd:888888".getBytes();// 2. 创建 DatagramPacket，包含所要发送的信息DatagramPacketpacket =newDatagramPacket(data,data.length,address,port);// 3. 创建 DatagramSocketDatagramSocketsocket =newDatagramSocket();// 4. 发送数据socket.send(packet);// 客户端接收服务器端的响应byte[]resp =newbyte[1024];DatagramPacketrespPacket =newDatagramPacket(resp,resp.length);socket.receive(respPacket);Stringinfo =newString(resp,0,respPacket.getLength());System.out.println("我是客户端，服务器响应的信息为：" +info);

6. 相关问题