request acquisition request parameter general manner

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);
 }
}