19.txt

java2应用开发指南第一版

例程19-1
//URLDemo.java
import java.net.*;
class URLDemo
{
	public URL aURL;
	public URLDemo(URL aURL)
	{
		this.aURL = URL;
	}
	public listDetails()
	{
		System.out.println(aURL.getProtocol());
		System.out.println(aURL.getHost());
		System.out.println(aURL.getFile());
		System.out.println(aURL.getPort());
		System.out.println(aURL.getRef());
	}
	public static void main(String args[])
	{
	 try
	 {
		URL url =new
 URL(“http://www.tsinghua.edu.cn:80/document/index.html#MAP”);
      }
	  catch(MalformedURLException e)
	  {
			e.printStackTrace();
      }
		URLDemo aURLDemo = new URLDemo(url);
		aURLDemo.listDetails();
	}
}



例程19-2
//ReadURLDemo.java
import java.net.*;
import java.io.*;
public class ReadURLDemo 
{
    public static void main(String[] args) throws Exception 
{
	   URL sina = new URL("http://www.sina.com.cn/index.htm");
	   BufferedReader in = new BufferedReader(
				new InputStreamReader(
				sina.openStream()));
String inputLine;
	  while ((inputLine = in.readLine()) != null)
	  System.out.println(inputLine);
	  in.close();
    }
}



例程19-3
// URLConnectionReader.java
import java.net.*;
import java.io.*;

public class URLConnectionReader 
{
    public static void main(String[] args) throws Exception 
{
        URL sina = new URL("http://www.sina.com.cn/");
        URLConnection sinaConn = yahoo.openConnection();
        BufferedReader in = new BufferedReader(
                                new InputStreamReader(
                                sinaConn.getInputStream()));
        String inputLine;
        while ((inputLine = in.readLine()) != null) 
            System.out.println(inputLine);
        in.close();
    }
}



例程19-4
// Reverse.java
import java.io.*;
import java.net.*;
public class Reverse 
{
    public static void main(String[] args) throws Exception 
{
	if (args.length != 1) {
	    System.err.println("Usage:  java Reverse "+ "string_to_reverse");
	    System.exit(1);
	}
	String stringToReverse = URLEncoder.encode(args[0]);
	URL url = new URL("http://java.sun.com/cgi-bin/backwards");
	URLConnection connection = url.openConnection();
	connection.setDoOutput(true);
	PrintWriter out = new PrintWriter(
                              connection.getOutputStream());
	out.println("string=" + stringToReverse);
	out.close();
	BufferedReader in = new BufferedReader(
				new InputStreamReader(
				connection.getInputStream()));
	String inputLine;
	while ((inputLine = in.readLine()) != null)
	    System.out.println(inputLine);
	in.close();
    }
}



例程19-5
// Address.java
import java.io.*;
import java.net.*;
public class Address
{
    public static void main(String[] args) throws IOException 
{
        if (args.length != 1) 
{
             System.out.println("Usage: java Address <hostname>");
             return;
        }
	   //通过计算机名称获取IP地址
	   InetAddress address = InetAddress.getByName(args[0]);
	   System.out.println(“输入的主机名称”+args[0]);
	   //通过IP地址获取计算机名称
       String strName = address.getHostName();
	   System.out.println(“程序获取的主机名称”+strName);
    }
}



例程19-6
//Main.java
import java.net.*;
import java.io.*;
class Main 
{
    public static void main (String[] args) 
{
try 
{
            URL url = new URL("http://java.sun.com/index.html");
            Object content = url.getContent();
          if (content != null) 
{
        System.out.println("class: " + content.getClass());
                    System.out.println("obj: " + content);
            }
            InputStream in = url.openStream();
            if (in != null) 
{
                for(int c = in.read(); c > 0; c = in.read()) 
{
                    System.out.print((char)c);
                 }
             }
}
catch (MalformedURLException e) 
{
              e.printStackTrace();
}
catch (IOException e) 
{
              e.printStackTrace();
}
}
}