ECharts and Java interface: How to quickly implement statistical charts such as line charts, bar charts, pie charts, etc.

ECharts and Java interface: How to quickly implement statistical charts such as line charts, bar charts, pie charts, etc., need specific code examples

With the advent of the Internet era, data Analytics are becoming increasingly important. Statistical charts are a very intuitive and powerful display method. Charts can display data more clearly, allowing people to better understand the connotation and patterns of the data. In Java development, we can use ECharts and Java interfaces to quickly display various statistical charts.

ECharts is a data visualization chart library based on HTML5 Canvas developed by Baidu. It can easily draw a variety of charts, including line charts, bar charts, pie charts, etc. The Java interface is a technology that enables back-end data to interact with front-end display, and can pass data to the front-end through Java code. Next, we will introduce how to use ECharts and Java interfaces to quickly display various statistical charts.

1. Implementing a line chart

A line chart is a chart that represents data trends by connecting data points. In ECharts, we can implement a line chart through the following code:

// 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: '折线图'
    },
    tooltip: {},
    legend: {
        data:['销量']
    },
    xAxis: {
        data: ["周一","周二","周三","周四","周五","周六","周日"]
    },
    yAxis: {},
    series: [{
        name: '销量',
        type: 'line',
        data: [5, 20, 36, 10, 20, 30, 40]
    }]
};

// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);

The above code shows how to use ECharts to implement a line chart. We can set various parameters of the chart in the option object, such as the title of the chart, the labels of the x-axis and y-axis, etc. By passing data to the data attribute in the series, the corresponding data can be displayed in the chart. Finally use the setOption method to render the chart.

How to implement a line chart in Java? We can pass data to the front end through the following Java code:

@RequestMapping("/echarts")
@ResponseBody
public Map<String,Object> echarts(){
    List<String> categories = new ArrayList<String>();
    categories.add("周一");
    categories.add("周二");
    categories.add("周三");
    categories.add("周四");
    categories.add("周五");
    categories.add("周六");
    categories.add("周日");

    List<Integer> data = new ArrayList<Integer>();
    data.add(5);
    data.add(20);
    data.add(36);
    data.add(10);
    data.add(20);
    data.add(30);
    data.add(40);

    Map<String,Object> result = new HashMap<String,Object>();
    result.put("categories",categories);
    result.put("data",data);

    return result;
}

In the above code, we create a Map object and put the x-axis and y-axis data into categories and data respectively. Then return the Map object to the front end.

Finally, add the following JS code to the front-end code to complete the back-end data rendering of the line chart:

$.ajax({
    url: '/echarts',
    type: 'get',
    success: function(data){
        var categories = data.categories;
        var data = data.data;
        var option = {
            title: {
                text: '折线图'
            },
            tooltip: {},
            legend: {
                data:['销量']
            },
            xAxis: {
                data: categories
            },
            yAxis: {},
            series: [{
                name: '销量',
                type: 'line',
                data: data
            }]
        };
        myChart.setOption(option);
    },
    error: function(){
        alert('error');
    }
});

2. Implementing the bar chart

A bar chart is a chart used to compare the size of different categories of data. In ECharts, we can implement histograms through the following code:

// 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: '柱状图'
    },
    tooltip: {},
    legend: {
        data:['销量']
    },
    xAxis: {
        data: ["周一","周二","周三","周四","周五","周六","周日"]
    },
    yAxis: {},
    series: [{
        name: '销量',
        type: 'bar',
        data: [5, 20, 36, 10, 20, 30, 40]
    }]
};

// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);

The above code shows how to use ECharts to implement histograms. Similar to the line chart, we can set various parameters of the chart in the option object, such as the title of the chart, the labels of the x-axis and y-axis, etc. At the same time, we only need to set the type attribute to 'bar' to convert the line chart into a bar chart.

How to implement a histogram in Java? We can pass data to the front end through the following Java code:

@RequestMapping("/echarts")
@ResponseBody
public Map<String,Object> echarts(){
    List<String> categories = new ArrayList<String>();
    categories.add("周一");
    categories.add("周二");
    categories.add("周三");
    categories.add("周四");
    categories.add("周五");
    categories.add("周六");
    categories.add("周日");

    List<Integer> data = new ArrayList<Integer>();
    data.add(5);
    data.add(20);
    data.add(36);
    data.add(10);
    data.add(20);
    data.add(30);
    data.add(40);

    Map<String,Object> result = new HashMap<String,Object>();
    result.put("categories",categories);
    result.put("data",data);

    return result;
}

In the above code, we create a Map object and put the x-axis and y-axis data into categories and data respectively. Then return the Map object to the front end. Add the following JS code to the front-end code to complete the back-end data rendering of the histogram:

$.ajax({
    url: '/echarts',
    type: 'get',
    success: function(data){
        var categories = data.categories;
        var data = data.data;
        var option = {
            title: {
                text: '柱状图'
            },
            tooltip: {},
            legend: {
                data:['销量']
            },
            xAxis: {
                data: categories
            },
            yAxis: {},
            series: [{
                name: '销量',
                type: 'bar',
                data: data
            }]
        };
        myChart.setOption(option);
    },
    error: function(){
        alert('error');
    }
});

3. Implementing the pie chart

The pie chart is a way to represent A chart of data proportions. In ECharts, we can implement pie charts through the following code:

// 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: '饼图',
        subtext: '数据来自网络'
    },
    tooltip: {
        trigger: 'item',
        formatter: '{a} <br/>{b}: {c} ({d}%)'
    },
    legend: {
        orient: 'vertical',
        left: 10,
        data: ['直接访问','邮件营销','联盟广告','视频广告','搜索引擎']
    },
    series: [
        {
            name: '访问来源',
            type: 'pie',
            radius: ['50%', '70%'],
            avoidLabelOverlap: false,
            label: {
                show: false,
                position: 'center'
            },
            emphasis: {
                label: {
                    show: true,
                    fontSize: '30',
                    fontWeight: 'bold'
                }
            },
            labelLine: {
                show: false
            },
            data: [
                {value: 335, name: '直接访问'},
                {value: 310, name: '邮件营销'},
                {value: 234, name: '联盟广告'},
                {value: 135, name: '视频广告'},
                {value: 1548, name: '搜索引擎'}
            ]
        }
    ]
};

// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);

The above code shows how to use ECharts to implement pie charts. Similar to line charts and bar charts, we can set various parameters of the chart in the option object, such as the title of the chart, the labels of the x-axis and y-axis, etc. By passing data to the data attribute in the series, the corresponding data can be displayed in the chart. Note that the pie chart data here needs to meet the format corresponding to the value and name, such as {value:335, name:'direct access'}.

How to implement a pie chart in Java? We can pass data to the front end through the following Java code:

@RequestMapping("/echarts")
@ResponseBody
public List<Map<String,Object>> echarts(){
    List<Map<String,Object>> result = new ArrayList<Map<String,Object>>();

    Map<String,Object> data1 = new HashMap<String,Object>();
    data1.put("value",335);
    data1.put("name","直接访问");
    result.add(data1);

    Map<String,Object> data2 = new HashMap<String,Object>();
    data2.put("value",310);
    data2.put("name","邮件营销");
    result.add(data2);

    Map<String,Object> data3 = new HashMap<String,Object>();
    data3.put("value",234);
    data3.put("name","联盟广告");
    result.add(data3);

    Map<String,Object> data4 = new HashMap<String,Object>();
    data4.put("value",135);
    data4.put("name","视频广告");
    result.add(data4);

    Map<String,Object> data5 = new HashMap<String,Object>();
    data5.put("value",1548);
    data5.put("name","搜索引擎");
    result.add(data5);

    return result;
}

In the above code, we create a Map array with 5 elements and store the values ​​and names in the Map. Then return the Map array to the front end. Add the following JS code to the front-end code to complete the back-end data rendering of the pie chart:

$.ajax({
    url: '/echarts',
    type: 'get',
    success: function(data){
        var legendData = [];
        var seriesData = [];
        $.each(data,function(index,item){
            legendData.push(item.name);
            seriesData.push(item);
        });

        var option = {
            title: {
                text: '饼图',
                subtext: '数据来自网络'
            },
            tooltip: {
                trigger: 'item',
                formatter: '{a} <br/>{b}: {c} ({d}%)'
            },
            legend: {
                orient: 'vertical',
                left: 10,
                data: legendData
            },
            series: [
                {
                    name: '访问来源',
                    type: 'pie',
                    radius: ['50%', '70%'],
                    avoidLabelOverlap: false,
                    label: {
                        show: false,
                        position: 'center'
                    },
                    emphasis: {
                        label: {
                            show: true,
                            fontSize: '30',
                            fontWeight: 'bold'
                        }
                    },
                    labelLine: {
                        show: false
                    },
                    data: seriesData
                }
            ]
        };
        myChart.setOption(option);
    },
    error: function(){
        alert('error');
    }
});

Summary:

Through the above examples, we can find that ECharts and Java interfaces are used to display statistics The chart is very simple. You only need to call the Java interface in the front-end code to obtain the data, and then pass it to the option object of ECharts. In the Java interface, the data needs to be encapsulated into a collection object such as Map or List first, and then returned to the front end. Naturally, it is more convenient to use Spring Boot. The combination of ECharts and Java interface can adapt to various development models with front-end and back-end separation.

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