public static void main(String args[]){
Set<String> set = new HashSet<String>();
for(int i=0;i<100000;i++){
String getRandomString = GetRandomString(11);
getRandomString= 8+getRandomString;
set.add(getRandomString);
}
System.out.println(set.size());
System.out.println("========");
// System.out.println(set.toString());
}
public static String GetRandomString(int Len) {
String[] baseString={"0","1","2","3",
"5","6","7","8","9"};
Random random = new Random();
int length=baseString.length;
String randomString="";
for(int i=0;i<length;i++){
randomString+=baseString[random.nextInt(length)];
}
random = new Random(System.currentTimeMillis());
String resultStr="";
for (int i = 0; i < Len; i++) {
resultStr += randomString.charAt(random.nextInt(randomString.length()-1));
}
return resultStr;
}
