request获取请求参数通用方式

package com.hopetesting.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.IOException;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * @author newcityman
 * @date 2019/8/31 - 18:20
 */
@WebServlet("/requestDemo06")
public class RequestDemo06 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        System.out.println("========");
        System.out.println(username + ":::" + password);
        String[] hobbies = request.getParameterValues("hobby");
        for (String hobby : hobbies) {
            System.out.println(hobby);
        }
        System.out.println("===================================");
        Enumeration<String> parameterNames = request.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            String s = parameterNames.nextElement();
            System.out.println(s);
            String parameter = request.getParameter(s);
            System.out.println(parameter);
        }
        System.out.println("++++++++++++++++++++++++++++++++++++");

        Map<String, String[]> parameterMap = request.getParameterMap();
        Set<String> strings = parameterMap.keySet();
        for (String name : strings) {
            String[] values = request.getParameterValues(name);
            System.out.println(name);
            for (String value : values) {
                System.out.println(value);
            }
            System.out.println("+++++++++++++++++++++++++++++++++++++++");
        }

    }

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