说明：  代理服务器打开一个端口接收浏览器发来的访问某个站点的请求，从请求的字符串中解析出用户想访问哪个网页，让后通过URL对象建立输入流读取相应的网页内容，最后按照web服务器的工作方式将网页内容发送给用户浏览器
(Proxy server to open a port to receive the browser sent a request to visit a site, from the request to resolve a string which the user would like to visit the page, so that after the object through the URL input stream to read the corresponding web content, and finally in accordance with the web server s working methods will Web content sent to the user s browser)