Request_獲取請求引數通用方式介紹以及方式演示

獲取請求引數通用方式：無論get還是post請求方式都可以使用下列方法來獲取請求引數

　　1.String getParameter(String name )：根據引數名稱獲取引數值   username=zhangsan&password=123

　　2.String getParameterValues(String name )：根據引數名稱獲取引數值的陣列   hobby=xx&hobby=game

　　3.Enumeration<String> getParameterNames()：獲取所有請求的引數名稱

　　4.Map<String,String[]> getParameterMap()：獲取所有引數的map集合

@WebServlet(name = "RequestDemo6", value = "/RequestDemo6")
public class RequestDemo6 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
//        //get獲取請求引數
//        String username = request.getParameter("username");
//        System.out.println("get");
//        System.out.println(username);

        this.doPost(request, response);
    }
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws
 
 ServletException, IOException {
//        post獲取請求引數
        String username = request.getParameter("username");
        /*System.out.println("post");
        System.out.println(username);*/

        //根據引數名稱獲取引數值的陣列
//        String[] hobbies = request.getParameterValues("hobby");
//        for (String hobby : hobbies) {
//            System.out.println(hobby);
//        }

        //獲取所有請求的引數名稱
        Enumeration<String> parameterNames = request.getParameterNames();
//        while (parameterNames.hasMoreElements()){
//            String s = parameterNames.nextElement();
//            System.out.println(s);
//            String[] hobbies = request.getParameterValues(s);
//            for (String hobby : hobbies) {
//                System.out.println(hobby);
//            }
//            System.out.println("--------------");
//        }

        //獲取所有引數的map集合
        Map<String, String[]> parameterMap = request.getParameterMap();
        //遍歷
        Set<String> strings = parameterMap.keySet();
        for (String string : strings) {

            //獲取鍵獲取值
            String[] strings1 = parameterMap.get(string);
            System.out.println(string);
            for (String s : strings1) {
                System.out.println(s);
            }

            System.out.println("-------------");
        }
    }
}