JFreeChart 画图，非常不错！

首先，需要把要用到的两个jar包下来，本例用的是jfreechart-1.0.10.jar，jcommon-1.0.13.jar。可以到该项目的官方网站上下载：http://www.jfree.org/

下面是jfreechart-1.0.10.jar包中org.jfree.chart.demo目录下的一个例子，看看他的效果，很不错哦！

 

 

以下是代码：

package com.test.jfreechart;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GradientPaint;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.CategoryLabelPositions;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.demo.BarChartDemo1;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;

public class BarChartDemo extends ApplicationFrame {

/**
* Creates a new demo instance.
*
* @param title
* the frame title.
*/
public BarChartDemo(String title) {
super(title);
CategoryDataset dataset = createDataset();
JFreeChart chart = createChart(dataset);
ChartPanel chartPanel = new ChartPanel(chart, false);
chartPanel.setPreferredSize(new Dimension(500, 270));
setContentPane(chartPanel);
}

/**
* Returns a sample dataset.
*
* @return The dataset.
*/
private static CategoryDataset createDataset() {

// row keys...
String series1 = "First";
String series2 = "Second";
String series3 = "Third";

// column keys...
String category1 = "Category 1";
String category2 = "Category 2";
String category3 = "Category 3";
String category4 = "Category 4";
String category5 = "Category 5";

// create the dataset...
DefaultCategoryDataset dataset = new DefaultCategoryDataset();

dataset.addValue(1.0, series1, category1);
dataset.addValue(4.0, series1, category2);
dataset.addValue(3.0, series1, category3);
dataset.addValue(5.0, series1, category4);
dataset.addValue(5.0, series1, category5);

dataset.addValue(5.0, series2, category1);
dataset.addValue(7.0, series2, category2);
dataset.addValue(6.0, series2, category3);
dataset.addValue(8.0, series2, category4);
dataset.addValue(4.0, series2, category5);

dataset.addValue(4.0, series3, category1);
dataset.addValue(3.0, series3, category2);
dataset.addValue(2.0, series3, category3);
dataset.addValue(3.0, series3, category4);
dataset.addValue(6.0, series3, category5);

return dataset;

}

/**
* Creates a sample chart.
*
* @param dataset
* the dataset.
*
* @return The chart.
*/
private static JFreeChart createChart(CategoryDataset dataset) {

// create the chart...
JFreeChart chart = ChartFactory.createBarChart("Bar Chart Demo 1", // chart
// title
"Category", // domain axis label
"Value", // range axis label
dataset, // data
PlotOrientation.VERTICAL, // orientation
true, // include legend
true, // tooltips?
false // URLs?
);

// NOW DO SOME OPTIONAL CUSTOMISATION OF THE CHART...

// set the background color for the chart...
chart.setBackgroundPaint(Color.white);

// get a reference to the plot for further customisation...
CategoryPlot plot = (CategoryPlot) chart.getPlot();
plot.setBackgroundPaint(Color.lightGray);
plot.setDomainGridlinePaint(Color.white);
plot.setDomainGridlinesVisible(true);
plot.setRangeGridlinePaint(Color.white);

// ******************************************************************
// More than 150 demo applications are included with the JFreeChart
// Developer Guide...for more information, see:
//
// > http://www.object-refinery.com/jfreechart/guide.html
//
// ******************************************************************

// set the range axis to display integers only...
final NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());

// disable bar outlines...
BarRenderer renderer = (BarRenderer) plot.getRenderer();
renderer.setDrawBarOutline(false);

// set up gradient paints for series...
GradientPaint gp0 = new GradientPaint(0.0f, 0.0f, Color.blue, 0.0f,
0.0f, new Color(0, 0, 64));
GradientPaint gp1 = new GradientPaint(0.0f, 0.0f, Color.green, 0.0f,
0.0f, new Color(0, 64, 0));
GradientPaint gp2 = new GradientPaint(0.0f, 0.0f, Color.red, 0.0f,
0.0f, new Color(64, 0, 0));
renderer.setSeriesPaint(0, gp0);
renderer.setSeriesPaint(1, gp1);
renderer.setSeriesPaint(2, gp2);

CategoryAxis domainAxis = plot.getDomainAxis();
domainAxis.setCategoryLabelPositions(CategoryLabelPositions
.createUpRotationLabelPositions(Math.PI / 6.0));
// OPTIONAL CUSTOMISATION COMPLETED.

return chart;

}

/**
* Starting point for the demonstration application.
*
* @param args
* ignored.
*/
public static void main(String[] args) {
BarChartDemo1 demo = new BarChartDemo1("Bar Chart Demo 1");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}

}