设计要求：
前端的HTML页面上有文本框用于输入一个整数，点击按钮后将文本框内的数提交给后端，后端对该数进行判断是否是素数，并将结果返回给前端，前端输出结果。
前端HTML页面（index.html）：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no" /> <title>Powered By Leisureeen</title> <script type="text/javascript"> function b_req() { var pr = document.getElementById("priN"); Request('IsPrime', 'post', 'priN=' + pr.value); } function Request(url, action, json) { var httpRequest = new XMLHttpRequest(); httpRequest.open(action, url, true); httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); httpRequest.send(json); httpRequest.onreadystatechange = function() { if (httpRequest.readyState == 4 && httpRequest.status == 200) { var json = httpRequest.responseText; alert(json); } }; } </script> </head> <body bgcolor="99EFFF"> <div align="center" style="line-height:30px;"> Please input a Integer: <br> <input type="text" id="priN" maxlength="8" value="18"> <br> <input type="submit" value="IsPrime" onclick="b_req()"> <br> </div> </body> </html>
web.xml文件：
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>IsPrime</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>IsPrime</servlet-name> <servlet-class>controller.IsPrimeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>IsPrime</servlet-name> <url-pattern>/IsPrime</url-pattern> </servlet-mapping> </web-app>
后端收发数据Java类（IsPrimeServlet.java）：
package controller; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import math.Prime; public class IsPrimeServlet extends HttpServlet{ protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException, IOException{ String str=req.getParameter("priN"); int n=Integer.parseInt(str); resp.setContentType("application/json; charset=utf-8"); resp.getWriter().println(str+(Prime.IsPrime(n)?" is":" is not")+" a prime number."); } }
后端素数判断Java类（Prime.java）：
package math; public class Prime{ public static boolean IsPrime(int n){ int i=0; if(n<=1) return false; for(i=2;i*i<=n;i++) if(n%i==0) return false; return true; } }