MVC标准流程图解
M:
package service; public class BmiService { public String bmi(double height,double weight,String gender){ String status = "正常"; double bmi = weight/height/height;//bmi指数等于体重除以身高的平方 if("m".equals(gender)){ if(bmi<20){ status = "过轻"; } if(bmi>25){ status="过重"; } }else{ if(bmi<19){ status = "过轻"; } if(bmi>24){ status="过重"; } } return "bmi："+bmi+"体重状况："+status; } }
V: 视图
<%@ page contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <html> <head> <title>Insert title here</title> </head> <body> <form action="bmi.do"> <fieldset> <legend>计算BMI指数</legend> 身高（米）：<input name="height"> 体重（公斤）：<input name="weight"> 性别：男<input type="radio" name="gender" value="m" checked="checked"> 女<input type="radio" name="gender" value="w"> <input type="submit" value="提交"> </fieldset> </form> </body> </html>
显示结果页面
<%@ page contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <html> <head> <title>Insert title here</title> </head> <body> ${status } </body> </html>
C:控制器
package web; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import service.BmiService; public class ActionServlet extends HttpServlet { private static final long serialVersionUID = 1L; protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /*控制器的职责： * 接收请求，依据请求路径，调用对应的模型来处理 */ String uri = request.getRequestURI();//获取资源路径 String path = uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));//通过处理请求资源路径获取用户的请求 System.out.println(path); if("/bmi".equals(path)){ String height = request.getParameter("height"); String weight = request.getParameter("weight"); String gender = request.getParameter("gender"); BmiService bmi = new BmiService(); String status = bmi.bmi(Double.parseDouble(height), Double.parseDouble(weight), gender); /* * 接收某型返回的结果，调用对应的视图来展现 */ request.setAttribute("status", status); request.getRequestDispatcher("/WEB-INF/view.jsp").forward(request, response); }else if("/toBmi".equals(path)){ request.getRequestDispatcher("/WEB-INF/bmi.jsp").forward(request, response);//转发写绝对路径 } } }
结构图：
