1.原理
2.使用步骤
附:readyState的5个属性值和status的3个属性值
3.演示示例,计算bmi(身体质量指数)
项目结构
前端页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>局部刷新 姓名
身高米
体重千克
请求映射
BmiServlet com.bjpowernode.controller.AjaxServlet BmiServlet /bmiAjax 服务器处理,AjaxServlet
package com.bjpowernode.controller; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; public class AjaxServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String name = request.getParameter("name"); String weight = request.getParameter("weight"); String height = request.getParameter("height"); Float h = Float.valueOf(height); Float w = Float.valueOf(weight); float bmi = w / (h * h); String msg = ""; if (bmi <= 18.5) { msg = "偏瘦!"; } else if (bmi > 18.5 && bmi <= 23.9) { msg = "正常!"; } else if (bmi > 24 && bmi <= 27) { msg = "偏胖!"; } else { msg = "肥胖!!"; } String ms="你好,"+name+"先生/女士,你的bmi为"+bmi+",你的身体状况为"+msg+""; response.setContentType("text/html;charset=utf-8"); PrintWriter out=response.getWriter(); out.print(ms); out.flush(); out.close(); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { super.doPost(req, resp); } }



