Socket

1、概述

　　　　　　1.1　　2个进程之间如果进行通信，必须唯一标识一个进程，在本地进程通信中，可以通过PID唯一标识一个进程；

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　在网络中，通过IP+PID唯一标识一个进程；

　　　　　　1.2　　Socket 是  对TCP、UDP等协议的抽象，是  操作系统  对外开放的接口：

　　　　　　　　　　　　

　　　　　　1.3　　Socket通信流程：

　　　　　　　　　　　　　　

　　　　　　1.4　　java的Socket实战：

　　　　　　　　　　　　

　　　　　　　　　　　　　　TCP实现：

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package com.an.socket.tcp;   import com.an.socket.Task; import java.io.IOException; import java.net.ServerSocket; import java.net.Socket;   public class TcpServer {       public static void main(String[] args){         ServerSocket serverSocket=null;         try {             //创建服务器端Socket，并绑定5888端口             serverSocket=new ServerSocket(5888);             while (true){                 //监听来自客户端向5888端口发送的信息                 Socket clientSocket =serverSocket.accept();                 //对接受到的信息执行相关处理                 new Task(clientSocket).start();             }         }catch (IOException ioe){             ioe.printStackTrace();         }     } }

　　

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package com.an.socket.tcp;   import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.Socket;   public class TcpClient {       public static void main(String[] args){         Socket socket=null;         InputStream inputStream=null;         OutputStream outputStream=null;         try {             //创建客户端Socket，并指向  服务器的Socket（IP+端口）             socket=new Socket("127.0.0.1",5888);             //获取Socket的输入、输出流             inputStream=socket.getInputStream();             outputStream=socket.getOutputStream();             //向服务器端发送字符串数据             outputStream.write(new String("Hello world").getBytes());             //接收到数据的长度             int receivedMsgLength=0;             //接收到数据存放的缓冲区             byte[] buffer=new byte[1024];             //读取服务器发送的数据             receivedMsgLength=inputStream.read(buffer);             System.out.println("client received msg from:"+receivedMsgLength);         }catch (IOException e){             e.printStackTrace();         }finally {             try {                 outputStream.close();                 inputStream.close();                 socket.close();             }catch (IOException ioe){                 ioe.printStackTrace();             }         }     } }

　　

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package com.an.socket;   import java.io.InputStream; import java.io.OutputStream; import java.net.Socket;   public class Task extends Thread {       private Socket socket;       public Task(){       }       public Task(Socket socket){         this.socket=socket;     }       @Override     public void run() {         OutputStream outputStream=null;         InputStream inputStream=null;         try {             outputStream=this.socket.getOutputStream();             inputStream=this.socket.getInputStream();             //读取的内容长度             int receivedMsgLength=0;             //读取数据存放的缓冲区             byte[] buffer=new byte[1024];             //读取客户端发送的数据             receivedMsgLength=inputStream.read(buffer);             //将读取的数据转为字符串             String receivedMsg=new String(buffer,0,receivedMsgLength);             System.out.println("server received msg from client:"+receivedMsg);             //向客户端回写接收到的字符串长度             outputStream.write(String.valueOf(receivedMsg.length()).getBytes());             //关闭资源             inputStream.close();             outputStream.close();             socket.close();         }catch (Exception e){             e.printStackTrace();         }     } }

　　

 　　　　　　　　　　　　　　UDP实现：

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package com.an.socket.udp;   import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket;   public class UdpServer {       public static void main(String[] args){         DatagramSocket datagramSocket=null;         try {             //创建服务器端Socket，并绑定5999端口             datagramSocket=new DatagramSocket(5999);             //接收到客户端发送存放的缓冲区             byte[] buffer=new byte[1024];             //将缓冲区数据封装到DatagramPacket中             DatagramPacket datagramPacket=new DatagramPacket(buffer,buffer.length);             //服务器接收来自客户端发送的消息             datagramSocket.receive(datagramPacket);             //从datagramPacket中读取接收到客户端的数据             byte[] bytes=datagramPacket.getData();             String receivedMsg=new String(bytes,0,bytes.length);             System.out.println("server received from client:"+receivedMsg);               //将接收到的数据转换为二进制             byte[] bytes1=String.valueOf(receivedMsg.trim().length()).getBytes();             //创建指向客户端 IP+端口的数据报             DatagramPacket toClientData=new DatagramPacket(bytes1,bytes1.length,datagramPacket.getAddress(),datagramPacket.getPort());             //发送数据给客户端             datagramSocket.send(toClientData);         }catch (IOException ioe){             ioe.printStackTrace();         }finally {             datagramSocket.close();         }     } }

　　

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package com.an.socket.udp;   import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress;   public class UdpClient {       public static void main(String[] args){         DatagramSocket datagramSocket=null;         try {             //创建客户端Socket             datagramSocket=new DatagramSocket();             //要发送给服务器的数据             byte[] sendMsg=new String("Hello world").getBytes();             //服务器IP             InetAddress serverAddress= InetAddress.getByName("127.0.0.1");             //封装  指向服务器IP+端口  数据报             DatagramPacket datagramPacket=new DatagramPacket(sendMsg,sendMsg.length,serverAddress,5999);             //向服务器发送数据             datagramSocket.send(datagramPacket);               //读取服务器发送的数据存放的缓冲区             byte[] buffer=new byte[1024];             //将接受的数据封装到数据报中             DatagramPacket receivedPacket=new DatagramPacket(buffer,buffer.length);             datagramSocket.receive(receivedPacket);             //从数据报中读取接受到的数据             byte[] bytes=receivedPacket.getData();             System.out.println(new String(bytes,0,receivedPacket.getLength()));         }catch (IOException ioe){             ioe.printStackTrace();         }finally {             datagramSocket.close();         }       } }