为什么使用HttpServletResponse时响应主体为空？

Question

这是我的servlet doGet（）方法的代码：

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {
    String admin = "true";
    resp.setContentType("text/plain");
    resp.setCharacterEncoding("UTF-8");
    PrintWriter writer = resp.getWriter();
    writer.write(admin);
    writer.flush();
}

它正确设置了内容类型和字符编码，但是响应主体为空。 我究竟做错了什么？

Answer 1

用这种方式

 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
    String admin = "true";

     resp.setContentType("text/plain; charset=utf-8");
     resp.setCharacterEncoding("UTF-8");

     PrintWriter out = resp.getWriter();
     try {

        out.println(admin);
     } finally {            
        out.close();
     }
}