简单Socket代码，理解Socket

服务器端Server[color=red][/color][size=large][/size]

package com.Socket;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServer {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ServerSocket svrsoc = null;
		Socket soc = null;
		DataInputStream in = null;
		PrintStream out = null;
		InetAddress clientIP = null;
		String str = null;
		
		try {
			svrsoc = new ServerSocket(8000);
			System.out.println("Server start.....");
			soc = svrsoc.accept();
			
                        //用于接收客户端发来的数据的输入流
			in = new DataInputStream(soc.getInputStream());
                        //用于向客户端发送数据的输出流
			out = new PrintStream(soc.getOutputStream());
			clientIP = soc.getInetAddress();
			System.out.println("Client IPAddress:"+clientIP);
			out.println("Welcome......");
			str = in.readLine();
			while(!str.equals("quit")){
				System.out.println("Client said:"+str);
				str = in.readLine();
			}
			System.out.println("Client want to leave....");
		} catch (IOException e) {
			e.printStackTrace();
		} finally{
			try{
			in.close();
			out.close();
			soc.close();
			svrsoc.close();
			System.exit(0);
			}catch (IOException e) {
				e.printStackTrace();
			}
		} 
	}

}

客户端端Client[color=red][/color][size=large][/size]

package com.Socket;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class TcpClient {
	public static void main(String[] args) {
		Socket soc = null;
		DataInputStream in = null;
		PrintStream out = null;
		DataInputStream sysin = null;
		String strin = null;
		String strout = null;

		try {
			soc = new Socket("localhost", 8000);
			System.out.println("Connecting to the Server....");
                        //获取输入流，用于接收服务器端发送来的数据
			in = new DataInputStream(soc.getInputStream());
                        //获取输出流，用于客户端向服务器端发送数据
			out = new PrintStream(soc.getOutputStream());
			strin = in.readLine();
			System.out.println("Server said:" + strin);
                        //用户输入流
			sysin = new DataInputStream(System.in);
			strout = sysin.readLine();
			while (!strout.equals("quit")) {
				out.println(strout);
				strout = sysin.readLine();
			}
			out.println(strout);
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (in != null) {
					in.close();
				} else if (out != null) {
					out.close();
				} else if (sysin != null) {
					sysin.close();
				} else if (soc != null) {
					soc.close();
				}

				System.exit(0);
			} catch (IOException e) {
			}
		}
	}
}

实现客户端Client输入字符串，服务器Server端显示输出