一个GZIP编码输出问题

如下代码为什么什么都显示不出来呢，应该能打印出hello world的啊，但是显示却是 雪白一边，这里假设浏览器支持gzip编码的，所以许多条件判断就省去了，希望哪位达人能指点迷津啊，代码如下
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
OutputStream out = null;
response.setHeader("Content-Encoding", "GZIP");
out=new GZIPOutputStream(response.getOutputStream());
String content="hello world";
PrintWriter pw = new PrintWriter(out);
pw.println(content);
pw.flush();
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException
{
doGet(request,response);
}