步骤说明:1,导入log4j.jar,jfreechart-0.9.18.jar,jcommon-0.9.3.jar三个jar包
2,在某个包中写入BarChart .java类
package com.mengya.util;
import java.awt.Color;import java.io.PrintWriter;
import javax.servlet.http.HttpSession;
import org.jfree.chart.ChartFactory;import org.jfree.chart.ChartRenderingInfo;import org.jfree.chart.ChartUtilities;import org.jfree.chart.JFreeChart;import org.jfree.chart.axis.AxisLocation;import org.jfree.chart.axis.CategoryAxis;import org.jfree.chart.axis.ValueAxis;import org.jfree.chart.entity.StandardEntityCollection;import org.jfree.chart.labels.StandardCategoryItemLabelGenerator;import org.jfree.chart.plot.CategoryPlot;import org.jfree.chart.plot.PlotOrientation;import org.jfree.chart.renderer.BarRenderer3D;import org.jfree.chart.servlet.ServletUtilities;import org.jfree.data.DefaultCategoryDataset;
public class BarChart {
private DefaultCategoryDataset dataset = new DefaultCategoryDataset();
public void setValue(int value, String rowKey, String columnKey) { dataset.setValue(value, rowKey, columnKey); }
public String generateBarChart(String title, HttpSession session,PrintWriter pw,int width,int heigth) { String filename = null; try { JFreeChart chart = ChartFactory .createBarChart3D(title, null, null, dataset, PlotOrientation.VERTICAL, true, false, false); chart.setBackgroundPaint(Color.WHITE); CategoryPlot plot = chart.getCategoryPlot();
CategoryAxis domainAxis = plot.getDomainAxis(); //domainAxis.setVerticalCategoryLabels(false); plot.setDomainAxis(domainAxis);
ValueAxis rangeAxis = plot.getRangeAxis(); // 设置最高的一个 Item 与图片顶端的距离 rangeAxis.setUpperMargin(0.15); // 设置最低的一个 Item 与图片底端的距离 rangeAxis.setLowerMargin(0.15); plot.setRangeAxis(rangeAxis);
BarRenderer3D renderer = new BarRenderer3D(); renderer.setBaseOutlinePaint(Color.BLACK); // 设置 Wall 的颜色 renderer.setWallPaint(Color.gray); // 设置每种水果代表的柱的颜色 renderer.setSeriesPaint(0, new Color(0, 0, 255)); renderer.setSeriesPaint(1, new Color(0, 100, 255)); renderer.setSeriesPaint(2, Color.GREEN); // 设置每个地区所包含的平行柱的之间距离 renderer.setItemMargin(0.1); // 显示每个柱的数值，并修改该数值的字体属性 //renderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator()); renderer.setItemLabelsVisible(true); plot.setRenderer(renderer);
// 设置柱的透明度 plot.setForegroundAlpha(0.6f); // 设置地区、销量的显示位置 plot.setDomainAxisLocation(AxisLocation.TOP_OR_RIGHT); plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_RIGHT); ChartRenderingInfo info = new ChartRenderingInfo( new StandardEntityCollection()); filename = ServletUtilities.saveChartAsPNG(chart, width, heigth, info, session); ChartUtilities.writeImageMap(pw, filename, info); pw.flush(); } catch (Exception e) { e.printStackTrace(); } return filename; }}
3,配置web.xml,在web.xml中添加如下内空: DisplayChart org.jfree.chart.servlet.DisplayChart DisplayChart /DisplayChart
4,在要显示图片的jsp中添加内容: 柱形图