Servlet 中利用阿里雲包fastjson-1.2.43.jar把map轉爲Json並返回前端

時間 2019-11-29

標籤 servlet 利用阿里 fastjson 1.2.43.jar jar map 轉爲 json 返回前端欄目 Tomcat 简体版

原文原文鏈接

1.引入fastjson-1.2.43.jar 包到lib下面，下載地址連接: https://pan.baidu.com/s/1EgAOikoG4VJRJrnUw83SNA 密碼: n2frjavascript

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");//取小數點後兩位四捨五入
        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轉爲json數據
      PrintWriter out = response.getWriter();
        out.write(json.toString());
        out.flush();
        out.close();
            }
}

　　前端jsp代碼入下html

<%--
  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>綜合測試</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="運算" id="btn"/>
</form>
<span>和爲:</span><span id="sum"></span></br>
<span>差爲:</span><span id="minus"></span></br>
<span>積爲:</span><span id="multiply"></span></br>
<span>商爲:</span><span id="divide"></span></br>
<script type="text/javascript">
	var reg = /^\d+(\.\d+)?$/;//判斷是數字
	$("#numA").blur(function () {
		var numA=$("#numA").val();
		 numA = $.trim(numA);
		if(numA=="") $("#A").text("numA爲空！"); 
		else if(reg.test(numA)==false) $("#A").text("numA不是數字！");
	});
	$("#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爲空！");
		else if(reg.test(numB)==false) $("#B").text("numB不是數字！");
		else if(numB==0) $("#B").text("error：分母不能爲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>

　　*注意若是出錯，請將fastjson-1.2.43.jar複製一份到tomcat 的lib 目錄下，而後重啓項目。前端