JFreeChart入门
JFreeChart主要用来各种各样的图表，这些图表包括：饼图、柱状图(普通柱状图以及堆栈柱状图)、线图、区域图、分布图、混合图、甘特图以及一些仪表盘等等
(源代码下载)
示例程序运用的jar包：
- jcommon-1.0.17.jar
- jfreechart-1.0.14.jar
1:普通柱状图
这是程序调用CategoryDataset dataset = getDataSet2(); 后所生产的图片
BarChartDemo.java柱状图代码
/** * 该类用于演示最简单的柱状图生成 * @author Winter Lau */ public class BarChartDemo { public static void main(String[] args) throws IOException{ CategoryDataset dataset = getDataSet2(); JFreeChart chart = ChartFactory.createBarChart3D( "水果产量图", // 图表标题 "水果", // 目录轴的显示标签 "产量", // 数值轴的显示标签 dataset, // 数据集 PlotOrientation.VERTICAL, // 图表方向：水平、垂直 true, // 是否显示图例(对于简单的柱状图必须是 false) false, // 是否生成工具 false // 是否生成 URL 链接 ); //中文乱码 CategoryPlot categoryplot = (CategoryPlot) chart.getPlot(); NumberAxis numberaxis = (NumberAxis) categoryplot.getRangeAxis(); CategoryAxis domainAxis = categoryplot.getDomainAxis(); TextTitle textTitle = chart.getTitle(); textTitle.setFont(new Font("黑体", Font.PLAIN, 20)); domainAxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 11)); domainAxis.setLabelFont(new Font("宋体", Font.PLAIN, 12)); numberaxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 12)); numberaxis.setLabelFont(new Font("黑体", Font.PLAIN, 12)); chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12)); FileOutputStream fos_jpg = null; try { fos_jpg = new FileOutputStream("D:\\BarChart.jpg"); ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f,chart,400,300,null); } finally { try { fos_jpg.close(); } catch (Exception e) {} } } /** * 获取一个演示用的简单数据集对象 * @return */ private static CategoryDataset getDataSet() { DefaultCategoryDataset dataset = new DefaultCategoryDataset(); dataset.addValue(100, "", "苹果"); dataset.addValue(200, "", "梨子"); dataset.addValue(300, "", "葡萄"); dataset.addValue(400, "", "香蕉"); dataset.addValue(500, "", "荔枝"); return dataset; } /** * 获取一个演示用的组合数据集对象 * @return */ private static CategoryDataset getDataSet2() { DefaultCategoryDataset dataset = new DefaultCategoryDataset(); dataset.addValue(100, "北京", "苹果"); dataset.addValue(100, "上海", "苹果"); dataset.addValue(100, "广州", "苹果"); dataset.addValue(200, "北京", "梨子"); dataset.addValue(200, "上海", "梨子"); dataset.addValue(200, "广州", "梨子"); dataset.addValue(300, "北京", "葡萄"); dataset.addValue(300, "上海", "葡萄"); dataset.addValue(300, "广州", "葡萄"); dataset.addValue(400, "北京", "香蕉"); dataset.addValue(400, "上海", "香蕉"); dataset.addValue(400, "广州", "香蕉"); dataset.addValue(500, "北京", "荔枝"); dataset.addValue(500, "上海", "荔枝"); dataset.addValue(500, "广州", "荔枝"); return dataset; } }
2：饼状图
PieChartDemo.java饼状图源代码
/** * 用于演示饼图的生成 */ public class PieChartDemo { public static void main(String[] args) throws IOException { DefaultPieDataset data = getDataSet(); JFreeChart chart = ChartFactory.createPieChart3D("水果产量图", // 图表标题 data, // 数据集 true, // 是否显示图例(对于简单的柱状图必须是 false) false, // 是否生成工具 false // 是否生成 URL 链接 ); //中文乱码 PiePlot3D plot = (PiePlot3D) chart.getPlot(); plot.setLabelFont(new Font("黑体", Font.PLAIN, 20)); TextTitle textTitle = chart.getTitle(); textTitle.setFont(new Font("黑体", Font.PLAIN, 20)); chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12)); // 写图表对象到文件，参照柱状图生成源码 FileOutputStream fos_jpg = null; try { fos_jpg = new FileOutputStream("D:\\Pie3DChart.jpg"); ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f, chart, 400, 300, null); } finally { try { fos_jpg.close(); } catch (Exception e) { } } } /** * 获取一个演示用的简单数据集对象 * * @return */ private static DefaultPieDataset getDataSet() { DefaultPieDataset dataset = new DefaultPieDataset(); dataset.setValue("苹果", 100); dataset.setValue("梨子", 200); dataset.setValue("葡萄", 300); dataset.setValue("香蕉", 400); dataset.setValue("荔枝", 500); return dataset; } }
其他的图表类型暂时不写了，其实写法也差不多。这里注意两种图形的中文乱码解决方法是不一样的，具体查看源代码中的红色部分
3：将数据库的内容用图形表示出来
index.jsp
<body>
<form action="servlet/ShowChartServlet" method="get" >
<input type="submit" value="jfreechart访问数据库生成图表">
</form>
</body>
showJfreeChart.jsp
<body>
<center>
<img alt="" src="<%=path %>/reports/productSales.jpg">
</center>
</body>
ShowChartServlet.java
public class ShowChartServlet extends HttpServlet { /** * 获取一个演示用的组合数据集对象 * * @return */ private static CategoryDataset getDataSet() { DefaultCategoryDataset dataset = new DefaultCategoryDataset(); // 从数据库中获取 Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); // 加载驱动程序 conn = DriverManager .getConnection( "jdbc:mysql://localhost:3306/shopping?useUnicode=true&characterEncoding=utf8", "root", "root"); ps = conn.prepareStatement("select p.name, count(pcount) from product p join salesitem si on (p.id = si.productid) group by p.id"); rs = ps.executeQuery(); while (rs.next()) { dataset.addValue(rs.getInt(2), "", rs.getString(1)); } rs.close(); rs = null; } catch (SQLException e) { e.printStackTrace(); }catch (ClassNotFoundException e) { e.printStackTrace(); } finally { if(ps != null){ try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } return dataset; } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { CategoryDataset dataset = getDataSet(); JFreeChart chart = ChartFactory.createBarChart3D( "产品销量图", // 图表标题 "产品", // 目录轴的显示标签 "销量", // 数值轴的显示标签 dataset, // 数据集 PlotOrientation.VERTICAL, // 图表方向：水平、垂直 true, // 是否显示图例(对于简单的柱状图必须是 false) false, // 是否生成工具 false // 是否生成 URL 链接 ); //中文乱码 CategoryPlot categoryplot = (CategoryPlot) chart.getPlot(); NumberAxis numberaxis = (NumberAxis) categoryplot.getRangeAxis(); CategoryAxis domainAxis = categoryplot.getDomainAxis(); TextTitle textTitle = chart.getTitle(); textTitle.setFont(new Font("黑体", Font.PLAIN, 20)); domainAxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 11)); domainAxis.setLabelFont(new Font("宋体", Font.PLAIN, 12)); numberaxis.setTickLabelFont(new Font("sans-serif", Font.PLAIN, 12)); numberaxis.setLabelFont(new Font("黑体", Font.PLAIN, 12)); chart.getLegend().setItemFont(new Font("宋体", Font.PLAIN, 12)); FileOutputStream fos_jpg = null; try { fos_jpg = new FileOutputStream("E:\\Workspaces\\MyEclipse 9\\WebProjects\\JFreeChart\\WebRoot\\reports\\productSales.jpg"); ChartUtilities.writeChartAsJPEG(fos_jpg, 1.0f,chart,400,300,null); String path = this.getServletContext().getContextPath(); System.out.println(path+"mmmmmmmmmmm"); this.getServletContext().getRequestDispatcher("/showJfreeChart.jsp").forward(request, response); } finally { try { fos_jpg.close(); } catch (Exception e) {} } } }
