查询域名服务器代码.doc

1 InetAddress类import .*;import java.io.*; public class HostLookuppublic static void main(String args)if(args.length0) for(int i=0;iargs.length;i+) System .out.println(lookup(argsi);/命令行带参数则使用参数 elseBufferedReader bin=new BufferedReader(new InputStreamReader(System.in);System.out.println(请输入主机名或IP地址，输入exit退出程序！);trywhile(true)System.out.print(主机名或IP地址：);String host=bin.readLine();/读取键盘输入 if(host.equalsIgnoreCase(exit) |host.equalsIgnoreCase(quit)break; System.out.println(lookup(host); /调用lookup方法转换输入的字符catch(IOException e)System.out.println(e);private static String lookup(String host)InetAddress addr;tryaddr=InetAddress.getByName(host);catch(UnknownHostException e)return cannot find host+host;if(isHostname(host)System.out.print(host+的IP地址为：);/是主机名return addr.getHostAddress();elseSystem.out.print(host+的主机名为：);/是IP地址return addr.getHostName(); private static boolean isHostname(String host)char ca=host.toCharArray();for(int i=0;ica.length;i+)if(!Character.isDigit(cai) if(cai!=.)return true;return false;2 URL类相关代码利用URL类获取网络资源import .URL;import java.io.BufferedReader;import java.io.InputStreamReader;public class TestURL public String getContent(String strUrl)/返回字符串，错误则返回error open url try URL url=new URL(strUrl); BufferedReader br=new BufferedReader(new InputStreamReader(url.openStream(); String s=; StringBuffer sb=new StringBuffer(); while(s=br.readLine()!=null) sb.append(s+rn); br.close(); return sb.toString(); catch(Exception e) return error open url + strUrl; public static void main(String args) TestURL ou=new TestURL();/具体使用方法System.out.println(ou.getContent(/services/index.jsp ); 3 URLConnection类一个具有IE功能的小型浏览器import java.awt.*;import java.awt.event.*;import javax.swing.*; import javax.swing.event.*;import java.io.*; import .*;public class browser extends JFrameJLabel jlabel;JTextField jtf;JEditorPane edpl;public browser()super(browser);Container con=getContentPane();jlabel=new JLabel(请输入要访问的网址:);jtf=new JTextField();jtf.addActionListener(new MyFieldDealing();JPanel panel=new JPanel();panel.setLayout(new GridLayout(2,1);panel.add(jlabel);panel.add(jtf);con.add(panel,BorderLayout.NORTH);edpl=new JEditorPane();edpl.setEditable(false);edpl.addHyperlinkListener(new MyHyperListener();con.add(new JScrollPane(edpl),BorderLayout.CENTER);setSize(600,800);setVisible(true);void getPage(String site)tryedpl.setPage(site); /在edpl中显示指定网页catch(IOException e)JOptionPane.showMessageDialog(this,连接错误,错误提示,JOptionPane.ERROR_MESSAGE);class MyEnter implements ActionListener /处理输入网址时的回车操作public void actionPerformed(ActionEvent e)String string=jtf.getText();getPage(string);class MyHyperListener implements HyperlinkListener/处理网页中的超链接public void hyperlinkUpdate(HyperlinkEvent e)if(e.getEventType()=HyperlinkEvent.EventType.ACTIVATED)String string=e.getURL().toString();/获取超链接指向的地址getP