绘制矩形边框粗细

如果要在 Graphics2D 对象上绘图，则可以使用以下方法：setStroke()

Graphics2D g2;
double thickness = 2;
Stroke oldStroke = g2.getStroke();
g2.setStroke(new BasicStroke(thickness));
g2.drawRect(x, y, width, height);
g2.setStroke(oldStroke);

如果这是在 Swing 组件上完成的，并且正在传递一个对象，则可以将其向下转换为 .GraphicsGraphics2D

Graphics2D g2 = (Graphics2D) g;

操作方法如下：用彩色线条边框，厚度为5。

Border linebor = BorderFactory.createLineBorder(new Color(0xAD85FF), 5);