package test; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.Authenticator; import java.net.HttpURLConnection; import java.net.PasswordAuthentication; import java.net.URL; import java.net.URLConnection; import java.util.Properties;   public class URLTest {  // 一个public方法，返回字符串，错误则返回"error open url"  public static String getContent(String strUrl) {   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 + "/r/n");    }    br.close();    return sb.toString();   } catch (Exception e) {    return "error open url:" + strUrl;   }  }    public static void initProxy(String host, int port, final String username,    final String password) {   Authenticator.setDefault(new Authenticator() {    protected PasswordAuthentication getPasswordAuthentication() {     return new PasswordAuthentication(username,       new String(password).toCharArray());    }   });   System.setProperty("http.proxyType", "4");   System.setProperty("http.proxyPort", Integer.toString(port));   System.setProperty("http.proxyHost", host);   System.setProperty("http.proxySet", "true");  }    public static void main(String[] args) throws IOException {    String url = "http://www.1sucai.cn";    String proxy = "http://192.168.22.81";    int port = 80;    String username = "username";    String password = "password";    String curLine = "";    String content = "";    URL server = new URL(url);    initProxy(proxy, port, username, password);    HttpURLConnection connection = (HttpURLConnection) server    .openConnection();    connection.connect();    InputStream is = connection.getInputStream();    BufferedReader reader = new BufferedReader(new    InputStreamReader(is));    while ((curLine = reader.readLine()) != null) {    content = content + curLine+ "/r/n";    }    System.out.println("content= " + content);    is.close();    System.out.println(getContent(url));  } }