我一直在寻找一种简单的Java算法来生成伪随机字母数字字符串。在我的情况下,它将被用作唯一的会话/密钥标识符,“很可能”在超过50万代的时间内是唯一的(我的需求实际上不需要更复杂的东西)。
理想情况下,我可以根据我的独特性需求指定长度。例如,生成的长度为12的字符串可能看起来像“AEYGF7K0DM1X”。
我一直在寻找一种简单的Java算法来生成伪随机字母数字字符串。在我的情况下,它将被用作唯一的会话/密钥标识符,“很可能”在超过50万代的时间内是唯一的(我的需求实际上不需要更复杂的东西)。
理想情况下,我可以根据我的独特性需求指定长度。例如,生成的长度为12的字符串可能看起来像“AEYGF7K0DM1X”。
当前回答
public class Utils {
private final Random RANDOM = new SecureRandom();
private final String ALPHABET = "0123456789QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm";
private String generateRandomString(int length) {
StringBuffer buffer = new StringBuffer(length);
for (int i = 0; i < length; i++) {
buffer.append(ALPHABET.charAt(RANDOM.nextInt(ALPHABET.length())));
}
return new String(buffer);
}
}
其他回答
最佳随机字符串生成器方法
public class RandomStringGenerator{
private static int randomStringLength = 25 ;
private static boolean allowSpecialCharacters = true ;
private static String specialCharacters = "!@$%*-_+:";
private static boolean allowDuplicates = false ;
private static boolean isAlphanum = false;
private static boolean isNumeric = false;
private static boolean isAlpha = false;
private static final String alphabet = "abcdefghijklmnopqrstuvwxyz";
private static boolean mixCase = false;
private static final String capAlpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final String num = "0123456789";
public static String getRandomString() {
String returnVal = "";
int specialCharactersCount = 0;
int maxspecialCharacters = randomStringLength/4;
try {
StringBuffer values = buildList();
for (int inx = 0; inx < randomStringLength; inx++) {
int selChar = (int) (Math.random() * (values.length() - 1));
if (allowSpecialCharacters)
{
if (specialCharacters.indexOf("" + values.charAt(selChar)) > -1)
{
specialCharactersCount ++;
if (specialCharactersCount > maxspecialCharacters)
{
while (specialCharacters.indexOf("" + values.charAt(selChar)) != -1)
{
selChar = (int) (Math.random() * (values.length() - 1));
}
}
}
}
returnVal += values.charAt(selChar);
if (!allowDuplicates) {
values.deleteCharAt(selChar);
}
}
} catch (Exception e) {
returnVal = "Error While Processing Values";
}
return returnVal;
}
private static StringBuffer buildList() {
StringBuffer list = new StringBuffer(0);
if (isNumeric || isAlphanum) {
list.append(num);
}
if (isAlpha || isAlphanum) {
list.append(alphabet);
if (mixCase) {
list.append(capAlpha);
}
}
if (allowSpecialCharacters)
{
list.append(specialCharacters);
}
int currLen = list.length();
String returnVal = "";
for (int inx = 0; inx < currLen; inx++) {
int selChar = (int) (Math.random() * (list.length() - 1));
returnVal += list.charAt(selChar);
list.deleteCharAt(selChar);
}
list = new StringBuffer(returnVal);
return list;
}
}
您可以为此使用Apache Commons库RandomStringUtils:
RandomStringUtils.randomAlphanumeric(20).toUpperCase();
我开发了一个应用程序,为我的项目开发一个自动生成的字母数字字符串。在这个字符串中,前三个字符是字母,后七个字符是整数。
public class AlphaNumericGenerator {
public static void main(String[] args) {
java.util.Random r = new java.util.Random();
int i = 1, n = 0;
char c;
String str = "";
for (int t = 0; t < 3; t++) {
while (true) {
i = r.nextInt(10);
if (i > 5 && i < 10) {
if (i == 9) {
i = 90;
n = 90;
break;
}
if (i != 90) {
n = i * 10 + r.nextInt(10);
while (n < 65) {
n = i * 10 + r.nextInt(10);
}
}
break;
}
}
c = (char)n;
str = String.valueOf(c) + str;
}
while(true){
i = r.nextInt(10000000);
if(i > 999999)
break;
}
str = str + i;
System.out.println(str);
}
}
public static String RandomAlphanum(int length)
{
String charstring = "abcdefghijklmnopqrstuvwxyz0123456789";
String randalphanum = "";
double randroll;
String randchar;
for (double i = 0; i < length; i++)
{
randroll = Math.random();
randchar = "";
for (int j = 1; j <= 35; j++)
{
if (randroll <= (1.0 / 36.0 * j))
{
randchar = Character.toString(charstring.charAt(j - 1));
break;
}
}
randalphanum += randchar;
}
return randalphanum;
}
我使用Math.random()使用了一个非常原始的算法。为了增加随机性,可以直接实现util.Date类。尽管如此,它还是有效的。
此外,您可以通过ASCII表中的数据生成任何小写或大写字母,甚至特殊字符。例如,生成从A(DEC 65)到Z(DEC 90)的大写字母:
String generateRandomStr(int min, int max, int size) {
String result = "";
for (int i = 0; i < size; i++) {
result += String.valueOf((char)(new Random().nextInt((max - min) + 1) + min));
}
return result;
}
generateRandomStr(65、90、100)的生成输出;:
TVLPFQJCYFXQDCQSLKUKKILKKHAUFYEXLUQFHDWNMRBIRRRWNXNNZQTINZPCTKLHGHVYWRKEOYNSOFPZBGEECFMCOKWHLHCEWLDZ