Java生成6位随机数(数字和拼音)Demo

public static void main(String[] args) {
　　//length = 6 生成的位数

    int length = 6;
    StringBuffer sb = new StringBuffer();
    String ALLCHAR = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    Random random = new Random();
    for (int i = 0; i < length; i++) {
        sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));
    }
    System.out.println(sb.toString());
}