java实现数字彩虹雨的程序。通过修改Color可改变彩虹雨的颜色。 此处字符随机，颜色随机，字符串生成位置随机。(Java program for digital rainbow rain. The color of the rainbows can be changed by modifying the Color. Here the characters are random, the colors are random, and the positions of the string