1、
第一种,获取一个随机的四位数
public static final char[] CHARAS={'1','2', '3', '4', '5', '6', '7', '8','9'};
public static Random random=new Random();
public static String getRandomString() {
StringBuilder buffer=new StringBuilder();
for (int i = 0; i <4; i++) {
buffer.append(CHARAS[random.nextInt(CHARAS.length)]);
}
return buffer.toString();
}
2、第二种,含有年月日,理论上是唯一的字符串
//生成一个随机证件号
public static String libraryCard() {
String Card = null;
char[] CHARAS={'1','2', '3', '4', '5', '6', '7', '8','9','0'};
Random random=new Random();
StringBuilder buffer=new StringBuilder();
for (int i = 0; i <5; i++) {
buffer.append(CHARAS[random.nextInt(CHARAS.length)]);
}
Date date = new Date();
SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
DecimalFormat df = new DecimalFormat("0000");
Card = formatter.format(date)
+ df.format(Integer.parseInt(buffer.substring(1, 5)));
return Card;
}
3、第三种
java.util.Random random=new java.util.Random();// 定义随机类
int result=random.nextInt(10);// 返回[0,10)集合中的整数,注意不包括10