写Java application时,如何设置proxy的信息,以便访问外部网站?

外行查资料得来，希望有帮助
若在java application中访问外部网站,首先应设置proxy信息,样例代码如下:

import java.util.properties;
.....
Properties sys = System.getProperties();
sys.put("proxySet","true");
sys.put("proxyHost","myHTTP.proxyserver.com");
sys.put("proxyPort","80");
System.setProperties(sys);
u = new URL(website);
connect = (HttpURLConnection)u.openConnection();
.....

:lol 不才。不懂这方面