web后端开发-实现Web端线上投票程序

package edu.hbun.work6.servlets; import java.io.IOException; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.annotation.WebInitParam; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class VoteServlet */ @WebServlet( urlPatterns = { "/voteservlet" }, initParams = { @WebInitParam(name = "isFirst", value = "1") }) public class VoteServlet extends HttpServlet { private static final long serialVersionUID = 1L; private int isFirst = -1; /** * @see HttpServlet#HttpServlet() */ public VoteServlet() { super(); // TODO Auto-generated constructor stub } /** * @see Servlet#init(ServletConfig) */ public void init(ServletConfig config) throws ServletException { //获取初始化参数，并赋值给属性 this.isFirst=Integer.parseInt(config.getInitParameter("isFirst")); } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub response.getWriter().append("Served at: ").append(request.getContextPath()); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取或创建整形数组 int[] voteResult = {0,0,0,0,0}; if(isFirst==1){ isFirst = 0;//创建 }else{ voteResult = (int[]) request.getServletContext().getAttribute("vr");//获取 } //更新投票数值 String[] choices = request.getParameterValues("fruits"); for(int i=0;i<choices.length;i++){ if("apple".equals(choices[i])){ voteResult[0]++; } else if("banana".equals(choices[i])){ voteResult[1]++; } else if("orange".equals(choices[i])){ voteResult[2]++; } else if("pear".equals(choices[i])){ voteResult[3]++; } else if("tomato".equals(choices[i])){ voteResult[4]++; } } //保存最新的投票结果 request.getServletContext().setAttribute("vr", voteResult); response.sendRedirect("voteseccess.html"); } }