java实现使用代理服务器创建URL连接

package cn.arthurs.web;
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.MalformedURLException;
import java.net.PasswordAuthentication;
import java.net.URL;
import java.util.Properties;
import org.apache.log4j.Logger;

public class WebUnit {
 private static final Logger log = Logger.getLogger( WebUnit.class );
 
 /**
  * 返回一个网站的源代码,需要传入一个网站的网址
  * @param webUrl
  * @return
  */
 public static String getWebContent(String webUrl){
  URL url;
  HttpURLConnection conn;
  InputStream stream;
  StringBuffer  text  =  new  StringBuffer();
  String temp="";
  try {
   url = new URL(webUrl);
   
   //如果需要代理服务器
   if(false){
      Properties prop = System.getProperties();       
      // 设置http访问要使用的代理服务器的地址          
      prop.setProperty("http.proxyHost", "bmcdc.bmsa.com");       
      // 设置http访问要使用的代理服务器的端口          
      prop.setProperty("http.proxyPort", "1865");       
      // 设置不需要通过代理服务器访问的主机，可以使用*通配符，多个地址用|分隔          
      prop.setProperty("http.nonProxyHosts", "localhost|10.4.*.*");       
      // 设置安全访问使用的代理服务器地址与端口        // 它没有https.nonProxyHosts属性，它按照http.nonProxyHosts 中设置的规则访问          
//      prop.setProperty("https.proxyHost", "bmccisa-dc02.bmccisa.com");          
//      prop.setProperty("https.proxyPort", "443");       
      // 使用ftp代理服务器的主机、端口以及不需要使用ftp代理服务器的主机          
//      prop.setProperty("ftp.proxyHost", "192.168.0.254");          
//      prop.setProperty("ftp.proxyPort", "2121");          
//      prop.setProperty("ftp.nonProxyHosts", "localhost|192.168.0.*");        // socks代理服务器的地址与端口          
//      prop.setProperty("socksProxyHost", "192.168.0.254");          
//      prop.setProperty("socksProxyPort", "8000");       
      // 设置登陆到代理服务器的用户名和密码          
      Authenticator.setDefault(new MyAuthenticator("[e-mail]", "f3mj"));
   }
   conn = (HttpURLConnection) url.openConnection();
   conn.connect();
   stream = conn.getInputStream();
   BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
   while((temp = reader.readLine()) != null){
    text.append(temp+"\n");
   }
  } catch (MalformedURLException e) {
   log.error("输入"+webUrl+"有误!!!");
  } catch (IOException e) {
   log.error(e);
  }
  return text.toString();
 }
 
 
 public static void main(String[] args){
//   System.out.println(WebUnit.getWebContent("http://www.baidu.com"));
  }
 
 static class MyAuthenticator extends Authenticator {       
  private String user = "";       
  private String password = "";       
  public MyAuthenticator(String user, String password) {           
   this.user = user;           
   this.password = password;          
  }       
  protected PasswordAuthentication getPasswordAuthentication() {          
   return new PasswordAuthentication(user, password.toCharArray());          
  }      
 }
}