《Java2图形设计卷II：Swing》配套光盘源码

				import java.awt.*;
				import java.awt.event.*;
				import javax.swing.*;
				import javax.swing.text.*;
				
				public class Test extends JApplet {
					public Test() {
						Container contentPane = getContentPane();
						JTextArea textArea = new JTextArea(
						  "File choosers, like option panes, are lightweight\n" +
						  "components that\n" +
						  "are meant to be placed ...");
				
						textArea.setCaret(new BoxHighlightingCaret());
						textArea.setFont(new Font("Dialog", Font.ITALIC, 24));
				
						contentPane.add(new JScrollPane(textArea), 
										BorderLayout.CENTER);
					}
				}
				class BoxHighlightingCaret extends DefaultCaret {
					private static BoxHighlighterPainter painter = 
												new BoxHighlighterPainter(null);
				
					public Highlighter.HighlightPainter getSelectionPainter(){
						return painter;
					}
					static class BoxHighlighterPainter 
						extends DefaultHighlighter.DefaultHighlightPainter {
						private Color color;
				
						public BoxHighlighterPainter(Color color) {
							super(color);
							this.color = color;
						}
						public Shape paintLayer(Graphics g, int p0, int p1, 
												Shape shape, JTextComponent comp,
												View view) {
							Rectangle b = shape.getBounds();
				
							try {
								g.setColor(getColor(comp));
				
								Rectangle r1 = comp.modelToView(p0);
								Rectangle r2 = comp.modelToView(p1);
				
								g.drawRect(r1.x, r1.y,  	 // x,y
											r2.x - r1.x - 1, // width
											r1.height - 1);  // height
							}
							catch(BadLocationException ex) {
								ex.printStackTrace();
							}
							return b;
						}
						private Color getColor(JTextComponent comp) {
							return color != null ? color : 
									   comp.getSelectionColor();
						}
					}
				}