(一)URL对象

• 目录

  网络基础知识

  通过URL读取www信息

  构造URL对象

  获取URL对象属性

  ---

• 网络基础知识

       Ipv4地址(32位,4个字节)
       Ipv6地址(128位,16个字节)
       主机名(hostname)如:www.tsinghua.edu.cn
       端口号(postnumber)如:80,21,23,1-1024为保留端口号
       服务类型(service)如:http,telnet,ftp,smtp

• 通过URL读取www信息

       Ipv4地址(32位,4个字节)
       Ipv6地址(128位,16个字节)
       主机名(hostname)如:www.tsinghua.edu.cn
       端口号(postnumber)如:80,21,23,1-1024为保留端口号
       服务类型(service)如:http,telnet,ftp,smtp

public class URLReader{
   public static void main(String[] args)throws Exception{
   URL cs=new URL("http://www.sina.com/");
   BufferedReader in=new BufferedReader(new InputStreamReader(cs.openStream()));
   String inputLine;
   while((inputLine=in.readLine())!=null)
      System.out.println(inputLine);
   in.close();   
  }
}

• 构造URL对象

public URL(String spec)
URL urlBase=new URL("http://www.gamelan.com/");

public URL(URL context,String spec)
URL gamelanGames=new URL(gamelan,"Gamelan.game.html");

public URL(String protocol,String host,String file);
URL gamelan=new URL("http","www.gamelan.com","/pages/Gamelan.net.html");

public URL(String protocol,String host,int port,String file);

URL gamelan=new URL("http","www.gamelan.com",80,"pages/Gamelan.network.html");

• 获取URL对象属性

public String getProtocol()
public String getHost()
public String getport()
public String getFile()
public String getRef()