jsp中画柱状图

<dependency>
    <groupId>org.jfree</groupId>
    <artifactId>jfreechart</artifactId>
    <version>1.5.0</version>
</dependency>

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtils;
import org.jfree.chart.JFreeChart;
import org.jfree.data.category.DefaultCategoryDataset;

import java.io.File;
import java.io.IOException;

public class BarChartExample {
    public static void createBarChart(String chartPath) throws IOException {
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(15, "Series1", "Category1");
        dataset.addValue(25, "Series1", "Category2");
        dataset.addValue(30, "Series1", "Category3");

        JFreeChart chart = ChartFactory.createBarChart(
                "Sample Bar Chart", // 图表标题
                "Category", // x轴标签
                "Value", // y轴标签
                dataset // 数据集
        );

        File chartFile = new File(chartPath);
        ChartUtils.saveChartAsPNG(chartFile, chart, 600, 400);
    }
}

<%@ page import="com.example.BarChartExample" %>
<%
    String chartPath = application.getRealPath("/") + "charts/sampleBarChart.png";
    try {
        BarChartExample.createBarChart(chartPath);
%>
<img src="charts/sampleBarChart.png" alt="Sample Bar Chart">
<%
    } catch (IOException e) {
        e.printStackTrace();
%>
<p>Failed to generate bar chart.</p>
<%
    }
%>