servlet 2.1 例子：查看请求头

html文件

header display




re

doGet方法体

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        
        PrintWriter out  = response.getWriter();
        out.println("");
        out.print("请求头消息：
");
        for(String name : Collections.list(request.getHeaderNames())){
            out.printf("%s : %s\n
", name, request.getHeader(name));
        }
        out.println("");
    }

打开网页显示的结果

如：http://localhost:8080/servletDemo/HeaderDisplay

请求头消息：
host : localhost:8080
connection : keep-alive
cache-control : max-age=0
upgrade-insecure-requests : 1
user-agent : Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36
accept : text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8
referer : http://localhost:8080/servletDemo/login.html
accept-encoding : gzip, deflate, sdch, br
accept-language : zh-CN,zh;q=0.8