java网络编程：socket与sockeserver

今晚上开始研究java的网络编程，先从socket开始吧。

java为TCP协议提供了两个类：Socket和Socketserver。一个Socket实例代表了TCP的一端，一个TCP连接是一条抽象的双向信道，两端分别由ＩＰ地址和端口号确定。在开始通信前，要建立一个ＴＣＰ连接，需要先由客户端TCP向服务端TCP发送连接请求。ServerSocket实例则监听TCP连接请求，并为每个请求创建新的Socket实例。

下面是一个简单的client/server的例子：

客户端代码：

//1.创建一个Socket实例,构造方法制定远程主机和端口建立一个TCP连接。
//2.通过套接字的输入输出流（I/O）进行通信，一个Socker连接实例包括InputStream和OutStream
//3.使用Socket类的close（）方法关闭连接
public class TCPECHOClient {
	public static void main(String[] args) {
		String server = "localhost";
		String data = "Echo this!";
		byte[] bs = data.getBytes();
		try {
			//创建一个套接字，并连接到由名字或IP地址指定的服务器
			Socket socket = new Socket(server,80);
			System.out.println("Connecting to server……");
			//获取输入输出流
			InputStream in = socket.getInputStream();
			OutputStream out = socket.getOutputStream();
			//发送字符串到回馈服务器
			out.write(bs);
			//接收回馈信息
			int totalDateRecived = 0;
			int bytesRecvd = 0 ;
			while(totalDateRecived<bs.length){
				totalDateRecived +=bytesRecvd;
				if((bytesRecvd=in.read(bs,totalDateRecived,bs.length-totalDateRecived))==-1)
				throw new SocketException("connection closed!");
			}
			System.out.println("received:"+new String(bs));
			socket.close();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

 服务端：

public class TCPEchoServer {
	private static int BUFSiZE = 32;
	public static void main(String[] args) {
		try {
			ServerSocket serverSocket = new ServerSocket(80);
			int received = 0;
			byte[] receiveBuf =  new byte[BUFSiZE];
			while(true){
				Socket socket = serverSocket.accept();
				//返回一个包含了客户端地址和端口号的InetSocketAddress实例
				SocketAddress clientAddress = socket.getRemoteSocketAddress();
				System.out.println("handling client at:"+clientAddress);
				InputStream in = socket.getInputStream();
				OutputStream out = socket.getOutputStream();
				while((received=in.read(receiveBuf))!=-1){
					out.write(receiveBuf,0,received);
				}
				socket.close();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

 输出结果：

客户端：Connecting to server……
received:Echo this!

服务端：handling client at:/127.0.0.1:50884