在iReport中通过JFreeChart生成雷达图（蜘蛛图）

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在iReport中通过JFreeChart生成雷达图（蜘蛛图）

日期：2010-07-13 | 分类：技术

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 http://gang613.blogbus.com/logs/69142477.html

    在iReport中提供了丰富的chart组件，包括：Pie、Pie 3D、Bar、YX Bar、Stacked Bar、Stacked Bar 3D、Line、XY Line、Area、YX Area、Stacked Area、Scatter、Bubble、Time Series、High Low、Candlestick、Gantt、Meter、Thermometer、Multi Axis 等。iReport为以上组件提供了相应的wizard，可以快速地在报表中输出chart。

    在我们的项目中用户需要在报表中生成雷达图（Spider Chart）——又名蜘蛛图，而这种chart在iReport中并没有相应的组件。我们发现通过jFreeChart能够生成Spider Chart，然后通过iReport对jFreeChart的调用完成在报表中输出Spider Chart 。
1）在报表中创建一个Image对象，如下图所示：

该Image的类型为：“java.awt.Image”，表达式为“$F{spiderimage}”其xml属性如下图：

字段spiderimage的类型为“java.awt.image.BufferedImage”

2）jFreeChart创建Spider Chart的代码如下：

/**
* 扩展了SpiderWebPlot,用于在显示刻度和说明。
* 来源于：http://javacrazyer.javaeye.com/blog/623741
*/

import java.awt.AlphaComposite;
import java.awt.Composite;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.font.LineMetrics;
import java.awt.geom.AffineTransform;
import java.awt.geom.Arc2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.text.NumberFormat;

import org.jfree.chart.plot.SpiderWebPlot;
import org.jfree.data.category.CategoryDataset;
public class MySpiderWebPlot extends SpiderWebPlot {
    private static final long serialVersionUID = 4005814203754627127L;
    private int ticks = DEFAULT_TICKS;
    private static final int DEFAULT_TICKS = 5;
    private NumberFormat format = NumberFormat.getInstance();
    private static final double PERPENDICULAR = 90;
    private static final double TICK_SCALE = 0.015;
    private int valueLabelGap = DEFAULT_GAP;
    private static final int DEFAULT_GAP = 10;
    private static final double THRESHOLD = 15;

    MySpiderWebPlot(CategoryDataset createCategoryDataset) {
        super(createCategoryDataset);
    }

    protected void drawLabel(final Graphics2D g2, final Rectangle2D plotArea,
            final double value, final int cat, final double startAngle,
            final double extent) {
        super.drawLabel(g2, plotArea, value, cat, startAngle, extent);
        final FontRenderContext frc = g2.getFontRenderContext();
        final double[] transformed = new double[2];
        final double[] transformer = new double[2];
        final Arc2D arc1 = new Arc2D.Double(plotArea, startAngle, 0, Arc2D.OPEN);
        for (int i = 1; i <= ticks; i++) {
            final Point2D point1 = arc1.getEndPoint();
            final double deltaX = plotArea.getCenterX();
            final double deltaY = plotArea.getCenterY();
            double labelX = point1.getX() - deltaX;
            double labelY = point1.getY() - deltaY;
            final double scale = ((double) i / (double) ticks);
            final AffineTransform tx = AffineTransform.getScaleInstance(scale,
                    scale);
            final AffineTransform pointTrans = AffineTransform
                    .getScaleInstance(scale + TICK_SCALE, scale + TICK_SCALE);
            transformer[0] = labelX;
            transformer[1] = labelY;
            pointTrans.transform(transformer, 0, transformed, 0, 1);
            final double pointX = transformed[0] + deltaX;
            final double pointY = transformed[1] + deltaY;
            tx.transform(transformer, 0, transformed, 0, 1);
            labelX = transformed[0] + deltaX;
            labelY = transformed[1] + deltaY;
            double rotated = (PERPENDICULAR);
            AffineTransform rotateTrans = AffineTransform.getRotateInstance(
                    Math.toRadians(rotated), labelX, labelY);
            transformer[0] = pointX;
            transformer[1] = pointY;
            rotateTrans.transform(transformer, 0, transformed, 0, 1);
            final double x1 = transformed[0];
            final double y1 = transformed[1];
            rotated = (-PERPENDICULAR);
            rotateTrans = AffineTransform.getRotateInstance(Math
                    .toRadians(rotated), labelX, labelY);
            rotateTrans.transform(transformer, 0, transformed, 0, 1);
            final Composite saveComposite = g2.getComposite();
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
                    1.0f));
            g2.draw(new Line2D.Double(transformed[0], transformed[1], x1, y1));
            if (startAngle == this.getStartAngle()) {
                final String label = format
                        .format(((double) i / (double) ticks)
                                * this.getMaxValue());
                final LineMetrics lm = getLabelFont()
                        .getLineMetrics(label, frc);
                final double ascent = lm.getAscent();
                if (Math.abs(labelX - plotArea.getCenterX()) < THRESHOLD) {
                    labelX += valueLabelGap;
                    labelY += ascent / (float) 2;
                } else if (Math.abs(labelY - plotArea.getCenterY()) < THRESHOLD) {
                    labelY += valueLabelGap;
                } else if (labelX >= plotArea.getCenterX()) {
                    if (labelY < plotArea.getCenterY()) {
                        labelX += valueLabelGap;
                        labelY += valueLabelGap;
                    } else {
                        labelX -= valueLabelGap;
                        labelY += valueLabelGap;
                    }
                } else {
                    if (labelY > plotArea.getCenterY()) {
                        labelX -= valueLabelGap;
                        labelY -= valueLabelGap;
                    } else {
                        labelX += valueLabelGap;
                        labelY -= valueLabelGap;
                    }
                }
                g2.setPaint(getLabelPaint());
                g2.setFont(getLabelFont());
                g2.drawString(label, (float) labelX, (float) labelY);
            }
            g2.setComposite(saveComposite);
        }
    }
}

/**
* 通过构造DefaultCategoryDataset创建Spider Chart。
*
*/
public class MySpriderWebPlotFactory {
    public static JFreeChart createChart() {
        MySpiderWebPlot spiderwebplot = new MySpiderWebPlot(createDataset());
        JFreeChart jfreechart = new JFreeChart("前三个季度水果销售报告",
                TextTitle.DEFAULT_FONT, spiderwebplot, false);
        LegendTitle legendtitle = new LegendTitle(spiderwebplot);
        legendtitle.setPosition(RectangleEdge.RIGHT);
        jfreechart.addSubtitle(legendtitle);
        return jfreechart;
    }

    public static DefaultCategoryDataset createDataset() {
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        String group1 = "苹果";

        dataset.addValue(50, group1, "一月份");
        dataset.addValue(60, group1, "二月份");
        dataset.addValue(40, group1, "三月份");
        dataset.addValue(20, group1, "四月份");
        // dataset.addValue(50, group1, "五月份");
        dataset.addValue(53, group1, "六月份");
        dataset.addValue(52, group1, "七月份");
        // dataset.addValue(80, group1, "八月份");

        String group2 = "橙子";
        dataset.addValue(31, group2, "一月份");
        dataset.addValue(34, group2, "二月份");
        dataset.addValue(45, group2, "三月份");
        dataset.addValue(74, group2, "四月份");
        // dataset.addValue(46, group2, "五月份");
        dataset.addValue(59, group2, "六月份");
        dataset.addValue(33, group2, "七月份");
        // dataset.addValue(31, group2, "八月份");

        String group3 = "香蕉";
        dataset.addValue(47, group3, "一月份");
        dataset.addValue(58, group3, "二月份");
        dataset.addValue(20, group3, "三月份");
        dataset.addValue(50, group3, "四月份");
        // dataset.addValue(65, group3, "五月份");
        dataset.addValue(67, group3, "六月份");
        dataset.addValue(44, group3, "七月份");
        // dataset.addValue(49, group3, "八月份");
        return dataset;
    }
}

3）将jFreeChart转换为BufferedImage

public BufferedImage extractImage(JFreeChart chart, int width, int height) {
    BufferedImage img = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = img.createGraphics();
    chart.draw(g2, new Rectangle2D.Double(0, 0, width, height));
    g2.dispose();
    return img;
}

4)定义ChartBean，用于封装数据。

public class ChartBean {
    java.awt.image.BufferedImage spiderimage;
    public ChartBean() {
    }
    public BufferedImage getSpiderimage(){
        return this.spiderimage;
    }
    public void setSpiderimage(BufferedImage spiderimage) {
        this.spiderimage = spiderimage;
    }
}

5)完成调用过程如下：

…
List charts = new ArrayList();
JFreeChart jfreechart = MySpiderWebPlotFactory.createChart();
BufferedImage bi = extractImage(jfreechart, 800, 600);
ChartBean chartBean = new ChartBean();
chartBean.setSpiderimage(bi);
charts.add(chartBean);
JRBeanCollectionDataSource ds = new JRBeanCollectionDataSource(charts);
…
try {
    JasperPrint jasperPrint = JasperFillManager.fillReport(rep,
            new HashMap（）, ds);
} catch (JRException jre) {
    pw.println("生成JasperPrint错误！");
    jre.printStackTrace();
}
…

最终生成效果图如下：

参考资料：

1）Using Dynamically Generated JFreeChart charts and JasperReports

2）使用JFreeChart生成带刻度的雷达图(蜘蛛网图)

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Tags：iReport Java

gang613 发表于12:42:33 | 编辑 | 分享　0

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