自制Border

public class BorderTest extends AbstractBorder{

protected Color lineColor;
protected int thick;
public BorderTest() {
this(Color.black, 6);
}
public BorderTest(Color lineColor, int thick) {
this.lineColor = lineColor;
this.thick = thick;
}
public static void main(String[] args){
JFrame f = new JFrame("a");
JPanel p = new JPanel();
p.setBorder(new BorderTest(Color.RED,6));
f.getContentPane().add(p);
f.setSize(400,600);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
public void paintBorder(Component c, Graphics g, int x,int y, int w, int h) {
Graphics copy = g.create();
if(copy != null) {
try {
copy.translate(x,y);
paintRectangle(c,copy,w,h);
paintHandles(c,copy,w,h);
}
finally {
copy.dispose();
}
}
}
public Insets getBorderInsets() {
return new Insets(thick,thick,thick,thick);
}
protected void paintRectangle(Component c, Graphics g,int w, int h) {
g.setColor(lineColor);
g.drawRect(thick/2,thick/2,w-thick-1,h-thick-1);
}
protected void paintHandles(Component c, Graphics g,int w, int h) {
g.setColor(lineColor);

g.fillRect(0,0,thick,thick); // upper left
g.fillRect(w-thick,0,thick,thick); // upper right
g.fillRect(0,h-thick,thick,thick); // lower left
g.fillRect(w-thick,h-thick,thick,thick); // lower right
g.fillRect(w/2-thick/2,0,thick,thick); // mid top
g.fillRect(0,h/2-thick/2,thick,thick); // mid left
g.fillRect(w/2-thick/2,h-thick,thick,thick); // mid bottom
g.fillRect(w-thick,h/2-thick/2,thick,thick); // mid right
}
}