HttpServletRequest

@Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        /*解决请求乱码*/
        request.setCharacterEncoding("UTF-8");

        /*常用方法*/
        /*获取项目名*/
        System.out.println("项目名:"+request.getContentType());
        /*获取客户机的地址*/
        System.out.println("客户机的地址:" + request.getRemoteAddr()+":"+request.getRemotePort());

        /*获取请求头的信息*/

        /*获取请求方式是*/
        System.out.println("请求方式:"+request.getMethod());

        /*获取请求的web项目名*/
        System.out.println("web项目名:"+request.getContextPath());

        /*获取指定名称请求头*/
        System.out.println("User-Agent头:"+request.getHeader("User-Agent"));

        /*获取所有的请求头的key*/
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String s = headerNames.nextElement();
            System.out.println(s + ":" + request.getHeader(s));
        }


        /*获取请求体的信息*/
        /*获取参数的Map集合*/
        Map<String, String[]> parameterMap = request.getParameterMap();
        Set<Map.Entry<String, String[]>> entries = parameterMap.entrySet();
        for (Map.Entry<String, String[]> s : entries) {
            String key = s.getKey();
            String[] val = s.getValue();
            System.out.println(key + ":" + Arrays.toString(val));
        }

        /*获取数据*/
        String name = request.getParameter("name");
        String pwd = request.getParameter("pwd");
        System.out.println(name + ":" + pwd);


        /*request的域对象*/
        /*声明周期：一次请求*/
        request.setAttribute("name","杨淏宇");
        System.out.println(request.getAttribute("name"));
        /*请求转发*/
        /*注意请求转发的路径不需要写项目名称*/
        request.getRequestDispatcher("/demo.jsp").forward(request,response);
        /*请求转发和重定向的区别：
        * 请求转发：请求服务器一次,地址栏不发生变化,适用于有参数的时候,服务器行为
        * 重定向：请求服务器两次,地址栏发生变化,使用于无参数的时候,浏览器行为
        */

    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

　　注意：tomcat 8 后不用解决请求乱码：

　　　　之前post用：request.setCharacterEncoding("UTF-8");

　　　　　　get用：parameter = new String(parameter.getBytes(“iso8859-1”),”UTF-8”); 注意只能解决一个乱码