1.从一个字符数组中任选四个字符
char[] charArr={"a","b","c","d"};StringBuilder sb= new StringBuilder();
Random rd = new Random();
for(int i=0;i<4;i++){
sb.append(charArr[rd.nextInt(charArr.length)]);
}
2.随机生成一种颜色
Random rd = new Random();
int r=rd.nextInt(256);
int b=rd.nextInt(256);
int color = Color.rgb(r,g,b);