//g对象为一个Graphics
FontMetrics fm = g.getFontMetrics ()；          
int strWidth = fm.stringWidth ("Registering plug-ins……")；          
int strHeight = fm.getHeight ()；  

转载：http://sbje5201314.blog.163.com/blog/static/280338620086332426488/

java计算字符串的宽度和高度