Socket基础知识-Java

socket 被翻译为“套接字”，它是计算机之间进行通信的一种方式。

socket源于Unix，而Unix/Linux基本哲学之一就是“一切皆文件”，都可以用“打开open –> 读写write/read –> 关闭close”模式来操作。

1. socket 服务端

package com.miselehe.io.study;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class SocketServerDemo {
	private static String UNICODE = "UTF-8";
	
	public void service () {
		System.out.println("服务启动！");
		
		// 监听端口
		int port = 12345;
		
		ServerSocket serverSocket = null;
		Socket socket = null;
		InputStream inputStream = null;
		OutputStream outputStream = null;
		
		try {
			// 启动socket 监听端口
			serverSocket = new ServerSocket(port);
			socket = serverSocket.accept();
			
			// 获得输入流接收信息
			inputStream = socket.getInputStream();
			byte[] b = new byte[1024];
			StringBuffer stringBuffer = new StringBuffer();
			while (inputStream.read(b) != -1) {
				stringBuffer.append(new String(b, UNICODE));
			}
			
			System.out.println("接收的信息为：" + stringBuffer);
			
			// 获得输出流发送信息
			outputStream = socket.getOutputStream();
			outputStream.write("Hi! 我是服务器!".getBytes(UNICODE));
			outputStream.flush();
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (inputStream != null) {
				try {
					inputStream.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (outputStream != null) {
				try {
					outputStream.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (socket != null) {
				try {
					socket.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (serverSocket != null) {
				try {
					serverSocket.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			System.out.println("服务关闭！");
		}
	}
	
	public static void main(String[] args) {
		SocketServerDemo socketServerDemo = new SocketServerDemo();
		socketServerDemo.service();
	}
	
}

2. socket 客户端

package com.miselehe.io.study;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class SocketClientDemo {
	
	private static String UNICODE = "UTF-8";
	
	public void sentInfo (String message) {
		// 服务端信息
		String server_host = "127.0.0.1";
		int server_port = 12345;
		
		Socket socket = null;
		OutputStream outputStream = null;
		InputStream inputStream = null;
		try {
			socket = new Socket(server_host, server_port);
			
			// 发送信息
			outputStream = socket.getOutputStream();
			outputStream.write(message.getBytes(UNICODE));
			outputStream.flush();
			System.out.println("信息已经发送！");
			// 告知服务器 发送信息完毕 （-1）  - 不可关闭输出流，关闭输出流socket也会关闭
			socket.shutdownOutput();
			
			// 接收服务器返回信息
			System.out.println("接收返回信息：");
			inputStream = socket.getInputStream();
			byte[] b = new byte[1024];
			while(inputStream.read(b) != -1) {
				System.out.println(new String(b));
			}
			
		} catch (UnknownHostException e) {
			// TODO Auto-generated catch block
			System.err.println("未知主机！");
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			System.err.println("链接异常！");
			e.printStackTrace();
		} finally {
			if (inputStream != null) {
				try {
					inputStream.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (outputStream != null) {
				try {
					outputStream.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (socket != null) {
				try {
					socket.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		
		
	}
	
	public static void main(String[] args) {
		SocketClientDemo socketClientDemo = new SocketClientDemo();
		socketClientDemo.sentInfo("您好，服务器哦!");
	}
}