Request获取请求参数通用方式介绍和实现

获取请求参数通用方式

• 获取请求参数通用方式：不论get还是post请求方式都可以使用下列方法来获取请求参数
  • String getParameter(String name)：根据参数名称获取参数值 username=zs&password=123
  • String[] getPara,eterValues(String name)：根据参数名称获取参数值的数组 hobby==xx&hobby=game
  • getParmeterNames()：获取所有请求参数名称
  • Enumeration getParameterNames()：获取所有请求的参数名称
  • Map<String,String[]> getParameterMap()：获取所有参数的map集合

package com.ailyt.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;

@WebServlet(value = "/r4")
public class RequestStudy4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
/*        //get获取请求参数
        //根据参数名称获取参数值
        String username = req.getParameter("username");
        System.out.println("get-->"+username);*/
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //post获取请求参数
        //根据参数名称获取参数值
        /*String username = req.getParameter("username");
        System.out.println("post-->"+username);*/

        //根据参数名获取参数值的数组
        /*String[] hobbies = req.getParameterValues("hobby");
        for (String hobby : hobbies) {
            System.out.println(hobby);
        }*/

        //获取所有请求的参数名称
        /*Enumeration<String> parameterNames = req.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            String name = parameterNames.nextElement();
            String value = req.getParameter(name);
            System.out.println(name);
            System.out.println(value);
        }*/

        //获取所有参数的Map集合
        Map<String,String[]> parameterMap = req.getParameterMap();
        parameterMap.forEach((name, strings) -> {
            for (String string : strings) {
                System.out.println(name+"-->"+string);
            }
        });

    }
}