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

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 = newURL(website);  connect =(HttpURLConnection)u.openConnection();  .....