Request获取请求参数通用方式的介绍和演示

Request获取请求参数通用方式的介绍

获取请求参数通用方式：不论是get还是post请求方式都可以使用下列方法来获取请求参数

　　1、String getParameter(String name)：根据参数名称获取参数值

　　2、String[] getParameterValues(String name)：根据参数名称获取参数值的数组　　

　　3、Enumeration<String> getParameterNames()：获取所有请求的参数名称

　　4、Map<String,String[]> g etParameterMap()：获取所有参数的map集合

package com.tomcat1.web.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Set;


@WebServlet("/requestDemo2")
public class RequestDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //post获取请求参数

        //1、String getParameter(String name)：根据参数名称获取参数值
        String username = request.getParameter("username");
/*        System.out.println("post");
        System.out.println(username);*/

        //2、String[] getParameterValues(String name)：根据参数名称获取参数值的数组　　
        String[] hobbies = request.getParameterValues("hobby");
        /*for (String hobby : hobbies) {
            System.out.println(hobby);
        }*/

        //3、Enumeration<String> getParameterNames()：获取所有请求的参数名称
        Enumeration<String> names = request.getParameterNames();
        /*while (names.hasMoreElements()){
            String s = names.nextElement();
            System.out.println(s);
            String parameter = request.getParameter(s);
            System.out.println(parameter);
            System.out.println("------------");
        }*/

        //4、Map<String,String[]> getParameterMap()：获取所有参数的map集合
        Map<String, String[]> parameterMap = request.getParameterMap();
        //遍历
        Set<String> keySet = parameterMap.keySet();
        for (String name : keySet) {
            //根据键获取值
            String[] strings = parameterMap.get(name);
            System.out.println(name);
            for (String string : strings) {
                System.out.println(string);
            }
            System.out.println("-----------");
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //get获取请求参数

        //根据参数名称获取参数值
        /*String username = request.getParameter("username");
        System.out.println("get");
        System.out.println(username);*/
        this.doPost(request,response);
    }
}