java 设置代理IP

   public static void main(String[] args) {        System.setProperty("http.maxRedirects", "50");        System.getProperties().setProperty("proxySet", "true");        String ip = "xxx.xxx.xxx.xxx";        String port="xxxx";        System.getProperties().setProperty("http.proxyHost", ip);        System.getProperties().setProperty("http.proxyPort", port);    }