老师这是哪里出错了？
来源：2-4 实现动态图表
衮雪TripleRock
2020-03-24 10:54:10
package com.imooc.total;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletRequest;
public class RequestTotalListener implements ServletContextListener,ServletRequestListener{
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
@Override
public void contextInitialized(ServletContextEvent sce) {
// TODO Auto-generated method stub
List timeList=new ArrayList();
List valueList=new ArrayList();
sce.getServletContext().setAttribute("timeList",timeList);
sce.getServletContext().setAttribute("valueList",valueList);
}
@Override
public void requestDestroyed(ServletRequestEvent sre) {
// TODO Auto-generated method stub
}
@Override
public void requestInitialized(ServletRequestEvent sre) {
HttpServletRequest request=(HttpServletRequest)sre.getServletRequest();
String url=request.getRequestURL().toString();
if(url.endsWith("/rt")==true) {
return;
}
// TODO Auto-generated method stub
// TimeList: 10:02 10:03 10:04
// ValueList: 5 7 10
List<String> timeList=(List)sre.getServletContext().getAttribute("timeList");
List<Integer> valueList=(List)sre.getServletContext().getAttribute("valueList");
Date date=new Date();
// 获取当前时间的小时，分钟
SimpleDateFormat sdf=new SimpleDateFormat("HH:mm");
String time=sdf.format(date);
//indexof()查找对应数据在集合中是否存在，不存在时为-1，存在时返回数据在集合中的位置
if(timeList.indexOf(time)==-1) {
timeList.add(time);
valueList.add(1);
sre.getServletContext().setAttribute("timeList",timeList);
sre.getServletContext().setAttribute("valueList",valueList);
}else {
int index=time.indexOf(time);
int value=valueList.get(index);
valueList.set(index,value+1);
sre.getServletContext().setAttribute("valueList",valueList);
}
}
}
package com.imooc.total;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
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 com.alibaba.fastjson.JSON;
/**
* Servlet implementation class RequestToralServlet
*/
@WebServlet("/rt")
public class RequestToralServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public RequestToralServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//得到全局对象
ServletContext context= request.getServletContext();
List<String> timeList=(List)context.getAttribute("timeList");
List<Integer> valueList=(List)context.getAttribute("valueList");
response.setContentType("text/html;charset=utf-8");
/*
* response.getWriter().println(timeList.toString());
* response.getWriter().println("<br/>");
* response.getWriter().println(valueList.toString());
*/
Map result =new HashMap();
result.put("timeList",timeList);
result.put("valueList",valueList);
String json =JSON.toJSONString(result);
response.getWriter().println(json);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>ECharts</title>
<script src="js/echarts.min.js"></script>
<script type="text/javascript" src="js/jquery-3.4.1.min.js"></script>
</head>
<body>
<div id="main" style="width: 600px;height:400px;"></div>
<script type="text/javascript">
function showChart(){
$.ajax({
url:"./rt",
type:"get",
dataType:"json",
success:function(json){
console.log(json.timeList);
console.log(json.valueList);
// 基于准备好的dom，初始化echarts实例
var myChart = echarts.init(document.getElementById('main'));
// 指定图表的配置项和数据
var option = {
title : {
text : '请求流量分析统计'
},
tooltip : {},
legend : {
data : [ '访问量' ]
},
xAxis : {
data : json.timeList
},
yAxis : {},
series : [ {
name : '访问量',
/*bar代表柱状图 line表示折线图*/
type : 'line',
data : json.valueList
} ]
};
// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);
}
})
}
//每隔1秒调用一次showChart()
window.setInterval("showChart()",1000);
</script>
</body>
</html>
老师每次访问的数据都会给第一个时间+1，而之后的时间一直赋值为1 不会增长
1回答
-
同学你好，错误如下:
应使用timeList.indexOf(),而不是time。
如果我的回答解决了你的疑惑，请采纳，祝学习愉快~
0
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