jsp页面中，注册时自动生成的检测码 有不同颜色，数字0-9和字母组成。 纯jsp代码-jsp page, the registration code generated automatically detect different colors, numbers 0-9 and letters. Pure jsp code

java小球碰撞检测：绘制图形界面，定义出是小球的颜色，位置，速度，实现多个小球碰撞后的反弹运动效果！-java ball collision detection: draw a graphical interface, define a color, position, speed of the ball to achieve the effect of multiple small ball collision rebound movement!