socket通信

socket通讯主要基于两种协议：一种是TCP协议，一种是UDP协议

1.TCP

TCP通信：tcp属于全双工连接，可以保证数据传输的安全性。一般分为服务器端和客户端。使用TCP协议连接所传递的数据不会丢失。通常使用在发短信，文件传输，发邮件等

测试代码：

服务器端：

import java.io.*;import java.net.ServerSocket;import java.net.Socket;public class TcpFileServer {    public static void main(String[] args) throws Exception { //创建服务器 ServerSocket serverSocket = new ServerSocket(8888); //监听服务器 Socket socket = serverSocket.accept(); //创建输入流 InputStream is = socket.getInputStream(); //创建文件输出流 FileOutputStream fos = new FileOutputStream(new File("D:\\LianXi\\Java\\demoLX\\src\\com\\demo1\\receive.png")); byte[] buffer = new byte[1024]; int len; while((len=is.read(buffer))!=-1){     fos.write(buffer,0,len); } //通知服务器我已经发送完毕 OutputStream outputStream = socket.getOutputStream(); outputStream.write("我已经接收完毕".getBytes()); outputStream.close(); fos.close(); is.close(); socket.close(); serverSocket.close();    }}

客户端：

package com.demo1;import java.io.*;import java.net.InetAddress;import java.net.Socket;import java.net.UnknownHostException;public class TcpFile {    public static void main(String[] args) throws Exception { //创建客户端 Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 8888); //创建输出流 OutputStream os = socket.getOutputStream(); //创建文件输出流 FileInputStream fos = new FileInputStream(new File("D:\\LianXi\\Java\\demoLX\\src\\com\\demo1\\aaa.png")); int len=0; byte[] buffer = new byte[1024]; while((len=fos.read(buffer))!=-1){     os.write(buffer,0,len); } //本次传输以及完成 socket.shutdownOutput(); //接收 InputStream stream = socket.getInputStream(); //内存转化 ByteArrayOutputStream baos = new ByteArrayOutputStream(); int len1; byte[] buffer1 = new byte[1024]; while((len1=stream.read(buffer1))!=-1){     baos.write(buffer1,0,len1); } System.out.println(baos.toString()); baos.close(); stream.close(); os.close(); socket.close();    }}

2.UDP

UDP是基于无连接的协议，不能保证数据的可靠性。

下面是用UDP实现多线程聊天室。

TalkSend

package com.demo2;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.*;public class TalkSend implements Runnable{    DatagramSocket socket=null;    InetAddress localhost=null;    BufferedReader reader=null;    private int fromPost;    private String toIp;    private int toPost;    public TalkSend(int fromPost,String toIp,int toPost) { this.fromPost=fromPost; this.toIp=toIp; this.toPost=toPost; try {     //建立一个socket连接     socket = new DatagramSocket();     reader = new BufferedReader(new InputStreamReader(System.in)); } catch (SocketException e) {     e.printStackTrace(); }    }    @Override    public void run() { while(true){     String str= null;     try {  str = reader.readLine();  //封装成包,参数:数据，数据起始长度，地址，端口号  DatagramPacket datagramPacket = new DatagramPacket(str.getBytes(),0,str.getBytes().length,   new InetSocketAddress(this.toIp,this.toPost));  //发送包  socket.send(datagramPacket);  if (str.equals("by")){      break;  }     } catch (IOException e) {  e.printStackTrace();     } } socket.close();    }}

TalkReceive

package com.demo2;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;public class TalkReceive implements Runnable{    private int port;    private String MessFrom;    DatagramSocket socket=null;    public TalkReceive(int port,String MessFrom) { this.MessFrom=MessFrom; this.port=port; //创建socket对象 try {     socket = new DatagramSocket(port); } catch (SocketException e) {     e.printStackTrace(); }    }    @Override    public void run() { try {     //监听数据     while(true){  byte[] buffer = new byte[1024];  DatagramPacket packet = new DatagramPacket(buffer,0,buffer.length);  //接收数据  socket.receive(packet);  String str=new String(packet.getData()).trim();  System.out.println(MessFrom+":"+str);  if (str.equals("by")){      break;  }     } } catch (IOException e) {     e.printStackTrace(); } socket.close();    }}

TalkStudent

package com.demo2;public class TalkStudent {    public static void main(String[] args) { new Thread(new TalkSend(7777,"localhost",8888)).start(); new Thread(new TalkReceive(9999,"老师")).start();    }}

TalkTeacher

package com.demo2;public class TalkTeacher {    public static void main(String[] args) { new Thread(new TalkSend(5555,"localhost",9999)).start(); new Thread(new TalkReceive(8888,"学生")).start();    }}

放在同一目录下运行TalkStudent和TalkTeacher两个文件

运行结果：

3.TCP和UDP的区别：

TCP/UDP协议更深层次的理解，三次握手，四次挥手等可以参考这篇文章：TCP/UDP协议

想了解更多的Java知识，可以关注我的微信公众号Java小羽。

说说控