页面不显示
来源：2-4 实现动态图表
MAYxDAY
2020-03-14 17:14:46
package com.imooc.total;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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 RequestTotalServlet
*/
@WebServlet("/rt")
public class RequestTotalServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public RequestTotalServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<String> timeList=(List)request.getServletContext().getAttribute("timeList");
List<String> valueList=(List)request.getServletContext().getAttribute("valueList");
response.setContentType("text/html:charset=UTF-8");
// response.getWriter().println(timeList.toString());
//
// 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);
}
}
********************************************
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/echarts.min.js"></script>
<script type="text/javascript" src="js/jquery-3.4.1.min.js"></script>
</head>
<body>
<!-- 为ECharts准备一个具备大小（宽高）的Dom -->
<div id="main" style="width: 600px;height:400px;"></div>
<script type="text/javascript">
function showTotal(){
$.ajax({
"url":"./rt",
"type":"get",
"dataType":"json",
"success":function(json){
console.info(json.timeList);
console.info(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',
type: 'line',
data: json.valueList
}]
};
// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);
}
})
}
window.setInterval("showTotal",1000);
</script>
</body>
</html>
2回答
-
同学你好，在html页面的js代码中，如下应该调用showTotal()函数，而不是showTotal，建议同学加上括号再试试。
修改后：
如果我的回答解决了你的疑惑，请采纳。祝：学习愉快~
1 -
MAYxDAY
提问者
2020-03-14
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 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;
}
List<String> timeList=(List)sre.getServletContext().getAttribute("timeList");
List<Integer> valueList=(List)sre.getServletContext().getAttribute("valueList");
Date date=new Date();
SimpleDateFormat sdf=new SimpleDateFormat("HH:mm");
String time=sdf.format(date);
if(timeList.indexOf(time)==-1) {
timeList.add(time);
valueList.add(1);
sre.getServletContext().setAttribute("timeList", timeList);
sre.getServletContext().setAttribute("valueList", valueList);
}else {
int index=timeList.indexOf(time);
int value=valueList.get(index);
valueList.set(index, value+1);
sre.getServletContext().setAttribute("valueList", valueList);
}
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
@Override
public void contextInitialized(ServletContextEvent sce) {
List<String> timeList=new ArrayList();
List<Integer> valueList=new ArrayList();
sce.getServletContext().setAttribute("timeList", timeList);
sce.getServletContext().setAttribute("valueList", valueList);
}
}
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