As the title suggest I need to create a random, 17 characters long, ID. Something like "AJB53JHS232ERO0H1". The order of letters and numbers is also random. I thought of creating an array with letters A-Z and a 'check' variable that randoms to 1-2. And in a loop;
Randomize 'check' to 1-2.
If (check == 1) then the character is a letter.
Pick a random index from the letters array.
else
Pick a random number.
But I feel like there is an easier way of doing this. Is there?
Here you can use my method for generating Random String
protected String getSaltString() {
String SALTCHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
StringBuilder salt = new StringBuilder();
Random rnd = new Random();
while (salt.length() < 18) { // length of the random string.
int index = (int) (rnd.nextFloat() * SALTCHARS.length());
salt.append(SALTCHARS.charAt(index));
}
String saltStr = salt.toString();
return saltStr;
}
The above method from my bag using to generate a salt string for login purpose.
Three steps to implement your function:
Step#1 You can specify a string, including the chars A-Z and 0-9.
Like.
String candidateChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
Step#2 Then if you would like to generate a random char from this candidate string. You can use
candidateChars.charAt(random.nextInt(candidateChars.length()));
Step#3 At last, specify the length of random string to be generated (in your description, it is 17). Writer a for-loop and append the random chars generated in step#2 to StringBuilder object.
Based on this, here is an example public class RandomTest {
public static void main(String[] args) {
System.out.println(generateRandomChars(
"ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", 17));
}
/**
*
* @param candidateChars
* the candidate chars
* @param length
* the number of random chars to be generated
*
* @return
*/
public static String generateRandomChars(String candidateChars, int length) {
StringBuilder sb = new StringBuilder();
Random random = new Random();
for (int i = 0; i < length; i++) {
sb.append(candidateChars.charAt(random.nextInt(candidateChars
.length())));
}
return sb.toString();
}
}
RandomStringUtils from Apache commons-lang might help:
RandomStringUtils.randomAlphanumeric(17).toUpperCase()
2017 update: RandomStringUtils has been deprecated, you should now use RandomStringGenerator.
You can easily do that with a for loop,
public static void main(String[] args) {
String aToZ="ABCD.....1234"; // 36 letter.
String randomStr=generateRandom(aToZ);
}
private static String generateRandom(String aToZ) {
Random rand=new Random();
StringBuilder res=new StringBuilder();
for (int i = 0; i < 17; i++) {
int randIndex=rand.nextInt(aToZ.length());
res.append(aToZ.charAt(randIndex));
}
return res.toString();
}
Source: Stackoverflow.com