第2章：基本套接字之TCP套接字

TCP客户端

 

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

public class TCPEchoClient {

	/**
	 * @param args
	 * @throws IOException 
	 * @throws UnknownHostException 
	 */
	public static void main(String[] args) throws UnknownHostException, IOException {
		if (args.length < 2 || args.length > 3)
			throw new IllegalArgumentException("Parameters:<Server> <Word> [<Port>]");

		String server = args[0];	//server name or ip address
		//Conver aaargument String to bytes using default character encoding
		byte[] data = args[1].getBytes();
		
		int servPort = (args.length == 3) ? Integer.parseInt(args[2]) : 7;
		
		//Create socket that is connected to server on special port
		Socket socket = new Socket(server,servPort);
		System.out.println("Connected to server ... sending echo string");
		
		InputStream in = socket.getInputStream();
		OutputStream out = socket.getOutputStream();
		
		out.write(data);    //send the encoded string to the server
		
		//receive the same string back from the server
		int totalByteRcvd = 0;   //total bytes received so far
		int bytesRcvd;			 //bytes received in last read
		while (totalByteRcvd < data.length) {
			if((bytesRcvd = in.read(data,totalByteRcvd,
							data.length-totalByteRcvd)) == -1)
			throw new SocketException("connection closed prematurely");
			totalByteRcvd += bytesRcvd;
		}  //data array is full
		
		System.out.println("Received:" + new String(data));
		
		socket.close();
	}

}

 

 

TCP服务器端

 

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;

public class TCPEchoServer {

	private static final int BUFSIZE =32;    //Size of reveive buffer
	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		if(args.length != 1)
			throw new IllegalArgumentException("Parameter: <Port>");
		
		int servPort = Integer.parseInt(args[0]);
		
		//create a server socket to accept client connection requests
		ServerSocket servSocke = new ServerSocket(servPort);
		
		int recvMsgSize;    //size of receive message
		byte[] receiveBuf = new byte[BUFSIZE];    //receive buffer
		
		while (true) {  //run forever,accepting and servicing connections
			Socket clntSock = servSocke.accept();    //get client connection
			SocketAddress clientAddress = clntSock.getRemoteSocketAddress();
			System.out.println("Handling client at " + clientAddress);
			
			InputStream in = clntSock.getInputStream();
			OutputStream out = clntSock.getOutputStream();
			
			//receive until client closes connection,indicated by -1 return
			while ((recvMsgSize = in.read(receiveBuf)) != -1) {
				out.write(receiveBuf,0,recvMsgSize);
			}
			clntSock.close();    //close the socket,we are done with this client!
		}
	}

}

 

 

注意：

 

1/TCP终端必须和特定的端口号关联，这样客户端才能够向该端口号发送链接请求

2/端口号第有效范围所0～65535（如果端口号被设为0，将选择任意没有使用第端口号）

 

测试方法：（需要打开2个控制台）

在控制台启动服务器端：输入   java TCPEchoServer 8000（也可以所范围内第任意端口）

在控制台启动客户端：   输入    java TCPEchoClient localhost “hello” 8000 （我这里向本地发送tcp请求）

 

我第输出所这样的——

服务器端输出：Handling client at /127.0.0.1:43389

客户端输出：Connected to server ... sending echo stringReceived:hello

成功了。

 

其实可以修改程序固定好服务器，端口号，内容等参数的，这样就不用在控制台里面输入那么多东西了，直接运行服务器端和客户端就行了，很简单的，这里不多说了，有兴趣第朋友可以改好了，发上来交流一下