Servlet 中利用阿里云包fastjson-1.2.43.jar把map转为Json并返回前端
1.引入fastjson-1.2.43.jar 包到lib下面，下载地址链接: https://pan.baidu.com/s/1EgAOikoG4VJRJrnUw83SNA 密码: n2fr
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
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.io.PrintWriter;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@WebServlet("/Servlet")
public class CalculateServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/json;charset=utf-8");
String numA = request.getParameter("numA");
String numB = request.getParameter("numB");
Float fnumA = Float.parseFloat(numA);
Float fnumB = Float.parseFloat(numB);
Float sum, minus, multiply, divide;
sum = fnumA + fnumB;
minus = fnumA - fnumB;
multiply = fnumA * fnumB;
divide = fnumA / fnumB;
DecimalFormat df = new DecimalFormat("#0.00");//取小数点后两位四舍五入
String sminus = df.format(minus);
String ssum = df.format(sum);
String smultiply = df.format(multiply);
String sdivide = df.format(divide);
Map<String,Object> map = new HashMap<String,Object>();
map.put("sum",ssum);
map.put("minus",sminus);
map.put("multiply",smultiply);
map.put("divide",sdivide);
JSONObject json = JSONObject.parseObject(JSON.toJSONString(map));//把map转为json数据
PrintWriter out = response.getWriter();
out.write(json.toString());
out.flush();
out.close();
}
}
前端jsp代码入下
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2017/12/18
Time: 14:59
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>综合测试</title>
<script src="static/js/jquery.js"></script>
</head>
<br>
<form id="f"><!--method="post" action="Servlet"-->
<label>numA:</label>
<input type="text" name="numA" id="numA" /><div id="A"></div><br/>
<label>numB:</label>
<input type="text" name="numB" id="numB" /><div id="B"></div><br/>
<input type="button" value="运算" id="btn"/>
</form>
<span>和为:</span><span id="sum"></span></br>
<span>差为:</span><span id="minus"></span></br>
<span>积为:</span><span id="multiply"></span></br>
<span>商为:</span><span id="divide"></span></br>
<script type="text/javascript">
var reg = /^\d+(\.\d+)?$/;//判断是数字
$("#numA").blur(function () {
var numA=$("#numA").val();
numA = $.trim(numA);
if(numA=="") $("#A").text("numA为空！");
else if(reg.test(numA)==false) $("#A").text("numA不是数字！");
});
$("#numA").focus(function () {
$("#A").empty();
});
$("#numB").blur(function () {
var numB=$("#numB").val();
numB = $.trim(numB);//去除空格符
if(numB=="") $("#B").text("numB为空！");
else if(reg.test(numB)==false) $("#B").text("numB不是数字！");
else if(numB==0) $("#B").text("error：分母不能为0！");
});
$("#numB").focus(function () {
$("#B").empty();
});
$("#btn").click(function () {
var numA=$("#numA").val();
var numB=$("#numB").val();
if(numA!=""&&numB!="")
$.get("/Servlet",$("#f").serialize(),function (data) {
console.log(data);
$("#sum").text(data.sum);
$("#minus").text(data.minus);
$("#multiply").text(data.multiply);
$("#divide").text(data.divide);
});});
</script>
</body>
</html>
*注意如果出错，请将fastjson-1.2.43.jar复制一份到tomcat 的lib 目录下，然后重启项目。
