How to use ECharts and Java interfaces to implement statistical analysis based on geographical location-javaTutorial-php.cn

How to use ECharts and Java interfaces to implement statistical analysis based on geographical location

With the continuous popularization of mobile devices and Internet technology, geographical location information has become a Very important data form. Using geographical location information, we can have an in-depth understanding of the market, the distribution of users and resources, as well as people's behavioral characteristics in different regions, so as to make more accurate decisions. In order to use geographical location information, we need to perform visual display based on maps, and be able to analyze and process the data on the map. ECharts is a very powerful data visualization tool. It provides a wealth of map components and chart components, which can help us quickly implement map-based statistical analysis. Java is currently one of the most popular web application development languages. It has a powerful and stable development framework and rich class libraries, which is very suitable for data processing and interface implementation. This article will introduce how to use ECharts and Java interfaces to implement statistical analysis based on geographical location, and provide code examples for readers' reference.

1. Preparation

Before introducing the specific implementation method, we need to understand some preliminary preparations. First, we need to prepare the map data. ECharts provides a wealth of map components, but the map data needs to be downloaded separately, so we need to go to the ECharts official website (http://echarts.baidu.com/) to download the required map data first. If you need to use the China map, you need to download china.js; if you need to use the city map, you need to download the js file of the corresponding city. After downloading the map data, we need to put it in the map folder of ECharts or other specified location. Secondly, we need to prepare the data interface. In the example of this article, we use Java language to implement the data interface and transmit data through JSON data format. Therefore, we need to add the relevant jar package to the Java project to support the JSON data format.

2. Implementation method

Before proceeding with specific implementation, we need to understand the basic components of ECharts. ECharts consists of three parts: options, events and data. Among them, option is the core component of ECharts, which defines the chart type, style, data and other information. Events are used to respond to user interactions, such as mouse movement, clicks, etc. Data is used to store the data to be presented. Through the cooperation of these three parts, we can achieve map-based data visualization and statistical analysis.

Basic map display

First, we need to create a basic map display page. In this page, we need to introduce ECharts and map data, and create a div container to store the map.

The following is a sample code for a basic map display page:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>基础地图展示</title>
  <!-- 引入ECharts -->
  <script src="http://echarts.baidu.com/build/dist/echarts.js"></script>
</head>
<body>
  <!-- 创建包含地图的div容器 -->
  <div id="main" style="width: 1000px;height:500px;"></div>
  <script>
    // 基于准备好的dom，初始化echarts实例
    var myChart = echarts.init(document.getElementById('main'));
    // 定义地图option
    var option = {
      tooltip : {
        trigger: 'item',
        formatter: '{b}'
      },
      series : [
        {
          type: 'map',
          map: 'china'
        }
      ]
    };
    // 使用地图option来初始化echarts实例
    myChart.setOption(option);
  </script>
</body>
</html>

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In this example, we create a div container containing a map by introducing the ECharts library and defining a specific map option. We define the content displayed in the floating layer when the mouse moves as the name of each area on the map, and specify the chart type and map data used through the type and map attributes in the series parameter.

Load data and display

Based on the map display, we need to load the actual data and display the data on the map. First, we need to create a Servlet in the Java project to handle data requests. The following is a simple example Servlet:

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MapServlet extends HttpServlet {
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // 准备要传输的数据
    String data = "{"data": [{"name":"北京","value":798}, {"name":"上海","value":346}, {"name":"广州","value":423}, {"name":"深圳","value":300}, {"name":"杭州","value":200}]}";
    response.setContentType("text/plain;charset=UTF-8");
    response.setHeader("Cache-Control","no-cache");
    PrintWriter out = response.getWriter();
    out.write(data);
    out.close();
  }
}

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The above Servlet will return a set of data in JSON format, which contains the names of several locations and corresponding values. This data will appear as markers on the map.

After obtaining the data, we need to process the data. In this example, we need to convert the read JSON data into an option format that ECharts can use. The following is a simple sample code:

var option = {
  tooltip : {
    trigger: 'item',
    formatter: '{b}'
  },
  series : [
    {
      type: 'map',
      map: 'china',
      data: []
    },
    {
      type: 'scatter',
      coordinateSystem: 'geo',
      data: []
    }
  ]
};
// 使用异步请求获取数据
$.get('/map', function (data) {
  var obj = JSON.parse(data);
  option.series[0].data = obj.data;
  option.series[1].data = obj.data;
  myChart.setOption(option);
});

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In this sample code, we obtain the data through an asynchronous request and format the data into the option object. Among them, series[0] represents map data, and series[1] represents marker point data. Because the value value in the marker point represents the specific value of the data, artificial standardization is required to map the value value to the size of the marker point.

Display data details

On the basis of map display, we can also provide more detailed data display. For example, at a marked point in a certain city, we can display the detailed data of the city, such as population, economic data, etc. The following is a sample code:

myChart.on('click', function (params) {
  if(params.componentSubType === 'scatter') {
    var name = params.name;
    var value = params.value[2];
    // 使用异步请求获取数据详情
    $.get('/details?name='+name, function (data) {
      // 显示数据详情
      alert('城市：'+name+'
数值：'+value+'
详情：'+data);
    });
  }
});

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In this sample code, we define a mouse click event. When a marker point is clicked, the data details of the location will be asynchronously requested and displayed.

3. Sample code

The above is how to use ECharts and Java interface to implement statistical analysis based on geographical location. The complete sample code can be viewed in the following github repository.

https://github.com/achangliu/ECharts-Map-JavaCode

Note: In the project, I used Mybatis as the database mapping tool and JSP as the template engine.

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