browser.java

java应用开发详解

import java.io.*;
import java.net.*;

public class Browser 
{
	//网址URL
	String urlString;
  	public static void main(String[] args) throws Exception 
  	{
     		if(args.length != 1) 
     		{
      			System.out.println("Usage: java Browser url");
      			System.exit(1);
     		}
     		Browser browser = new Browser(args[0]);
     		browser.run();
  	}

  	public Browser(String urlString) 
  	{
     		this.urlString = urlString;
  	}

  	public void run() throws Exception 
  	{
     		//生成一个URL对象
     		URL url = new URL(urlString);
     		//得到输入流
     		HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
     		//打印头信息
     		System.out.println("THE HEADERS");
     		System.out.println("-----------");
     		for(int i=1;;++i) 
     		{
       			String key;
       			String value;
       			if((key = urlc.getHeaderFieldKey(i)) == null) break;
       			if((value = urlc.getHeaderField(i)) == null) break;
       			System.out.print(key);
       			System.out.println(" is: " + value);
     		}
     		
     		//得到输入流
     		BufferedReader reader = new BufferedReader(
     			new InputStreamReader(urlc.getInputStream()));
     		String line;
     		System.out.println("-----CONTENT------");
     		while((line = reader.readLine()) != null) System.out.println(line);
  	}
}