sun官方论坛的代码：

import java.awt.*;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;
         ...
        //to modify the color of the lines : 
         Plot plot = jfreechart.getPlot();
         plot.setDrawingSupplier(getSupplier());
         ...
 
    private static Color myBlue=new Color(0,128,255);
    public static DefaultDrawingSupplier getSupplier(){
        return new DefaultDrawingSupplier(
                new Paint[] {
             myBlue,
                     Color.green,
                     Color.red,
                     Color.orange,
                     Color.magenta,
                     Color.cyan,
                     Color.pink,
                     Color.gray,
                     Color.yellow,
                     ChartColor.DARK_RED,
                     ChartColor.DARK_GREEN,
                     ChartColor.LIGHT_RED,
                     ChartColor.DARK_YELLOW,
                     ChartColor.DARK_MAGENTA,
                     ChartColor.DARK_CYAN,
                     Color.lightGray,
                     ChartColor.LIGHT_RED,
                     ChartColor.LIGHT_BLUE,
                     ChartColor.LIGHT_GREEN,
                     ChartColor.LIGHT_YELLOW,
                     ChartColor.LIGHT_MAGENTA,
                     ChartColor.LIGHT_CYAN},
                 DefaultDrawingSupplier.DEFAULT_OUTLINE_PAINT_SEQUENCE,
                             DefaultDrawingSupplier.DEFAULT_STROKE_SEQUENCE,
                             DefaultDrawingSupplier.DEFAULT_OUTLINE_STROKE_SEQUENCE,
                             DefaultDrawingSupplier.DEFAULT_SHAPE_SEQUENCE
                             );
    }