request方法总结

 1.获得指定的头

String header = response.getHeader("user-agent");

2.获得所有头的名称

Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {// 判断是否还有下一个元素
            String nextElement = headerNames.nextElement();// 获取headerNames集合中的请求头
            String header2 = request.getHeader(nextElement);// 通过请求头得到请求内容
            System.out.println(nextElement + ":" + header2);
        }

3.获取请求方式

     String method = request.getMethod();

4.获得请求的资源

     String requestURI = request.getRequestURI();
     StringBuffer requestURL = request.getRequestURL();

5.获取web应用的地址名称

String contextPath = request.getContextPath();

6.获取地址后的参数字符串

String queryString = request.getQueryString();

7.获取客户端信息--获得IP地址

String remoteAddr = request.getRemoteAddr();

8.获取单个表单中的value值

String usernam = request.getParameter("usernam");

9.获取多个表单的value值

String[] parameterValues = request.getParameterValues("hobby");
        System.out.print("hobby.values:");
        for (String string : parameterValues) {
            System.err.print(string + "  ");
        }

10.获得所有参数的name

Enumeration<String> parameterNames = request.getParameterNames();
        for (String string2 : parameterValues) {
            System.out.println(parameterNames.nextElement());
        }

11.将获得的所有参数封装到一个Map<String,String[]>中

Map<String, String[]> parameterMap = request.getParameterMap();
        for (Map.Entry<String, String[]> entry : parameterMap.entrySet()) {
            System.out.println(entry.getKey());
            for (String string : entry.getValue()) {
                System.out.println(string);
            }
            System.out.println("----------------");
        }

12.跳转方式

1.转发：地址不变
 request.getRequestDispatcher("path").forward(request, response);
2.重定向：地址改变
response.sendRedirect(path);

13.向request域中存储和取出数据 

request.setAttribute("name", "value");
request.getAttribute("name");