JDK6.0学习笔记（十六）登陆需要认证的站点

1. /**
2.  * 登陆需要认证的站点
3.  * 输入命令  http://127.0.0.1 user password 
4.  * */
6. import java.io.PrintWriter;
7. import java.io.InputStream;
8. import java.io.InputStreamReader;
9. import java.io.BufferedReader;
10. import java.io.StringWriter;
11. import java.io.IOException;
12. import java.net.URL;
13. import java.net.Authenticator;
14. import java.net.PasswordAuthentication;
15. import java.net.MalformedURLException;
17. public class TestAuthenticator {
18.     public static void main(String[] args) {
19.         Authenticator.setDefault(new MyAuthenticator(args[1], args[2]));//获取用户名和密码
20.         System.out.println(new TestAuthenticator().fetchURL(args[0]));
21.     }
23.     private String fetchURL(String urlString) {//读出网站内容
24.         StringWriter sw = new StringWriter();
25.         PrintWriter pw = new PrintWriter(sw);
26.         try {
27.             URL url = new URL(urlString);
28.             InputStream content = (InputStream) url.getContent();
29.             BufferedReader in = new BufferedReader(new InputStreamReader(
30.                     content));
31.             String line;
32.             while ((line = in.readLine()) != null) {
33.                 pw.println(line);
34.             }
35.         } catch (MalformedURLException e) {
36.             pw.println("URL无效");
37.         } catch (IOException e) {
38.             pw.println("读取URL资源时出错");
39.         }
40.         return sw.toString();
41.     }
42. }
44. class MyAuthenticator extends Authenticator {//Authenticator类
45.     private String user = null;
47.     private String password = null;
49.     public MyAuthenticator(String user, String password) {
50.         this.user = user;
51.         this.password = password;
52.     }
54.     protected PasswordAuthentication getPasswordAuthentication() {//返回的PasswordAuthentication对象中给出用户名和密码
55.         char[] ch = new char[this.password.length()];
56.         password.getChars(0, this.password.length(), ch, 0);
57.         return new PasswordAuthentication(this.user, ch);
58.     }
59. }