echoclient.java

简单的用java完成消息传输的例程

//: c15:JabberClient.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Very simple client that just sends
// lines to the server and reads lines
// that the server sends.

/*
C/S客户端应用
程序功能:完成C/S架构的客户端访问程序,访问服务端的8080端口,自身输出端口由系统自动分配一个1024以上的闲置端口.
作用:向服务发送请求,接收服务端返回数据.并输出显示
原理:首先解析服务端IP地址,通过服务端地址建立Socket实例,并通过该实例发送请求,和接收反射信息.
*/

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;

public class EchoClient {
	public static void main(String[] args) throws IOException {
		// Passing null to getByName() produces the
		// special "Local Loopback" IP address, for
		// testing on one machine w/o a network:
		InetAddress addr;				//Java内部类解析IP地址
		if (args.length >= 1) {			
			addr = InetAddress.getByName(args[0]);	//从调用参数中获得服务端IP
		} else {
			addr = InetAddress.getByName(null);		//如果没有参数则默认为本机IP
		}
		// Alternatively, you can use 
		// the address or name:
		// InetAddress addr = 
		//    InetAddress.getByName("127.0.0.1");
		// InetAddress addr = 
		//    InetAddress.getByName("localhost");
		System.out.println("addr = " + addr);
		Socket socket = new Socket(addr, EchoServer.PORT);		//通过服务端地址和服务端口建立Socket实例
		// Guard everything in a try-finally to make
		// sure that the socket is closed:
		try {
			System.out.println("socket = " + socket);
			BufferedReader in =
				new BufferedReader(
					new InputStreamReader(socket.getInputStream()));	//建立输入流实例,转换字节流到字符流
			// Output is automatically flushed
			// by PrintWriter:
			PrintWriter out =
				new PrintWriter(
					new BufferedWriter(								//设置状态实时响应 "true"
						new OutputStreamWriter(socket.getOutputStream())),true);  	//建立输出流实例,转换字符流到字节流
			BufferedReader input =
				new BufferedReader(new InputStreamReader(System.in)); //建立从键盘输入流实例
			while (true) {
				String str = input.readLine();   //由键盘数据
				out.println(str);				//输出到端口,并发送给服务端
				if (str.equals("END"))			//END进程结束
					break;
				String strSocket = in.readLine();	//接收返回信息
				System.out.println(strSocket);		//屏幕输出返回信息
			}
			/* for(int i = 0; i < 10; i ++) {
			   out.println("howdy " + i);
			   String str = in.readLine();
			   System.out.println(str);
			 } 
			 out.println("END"); */
		} finally {
			System.out.println("closing...");
			socket.close();				//关闭端口对象
		}
	}
} ///:~