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
您可以创建一个包含所有字母和数字的字符数组,然后可以从该字符数组中随机选择并创建自己的字符串密码。
char[] chars = new char[62]; // Sum of letters and numbers
int i = 0;
for(char c = 'a'; c <= 'z'; c++) { // For letters
chars[i++] = c;
}
for(char c = '0'; c <= '9';c++) { // For numbers
chars[i++] = c;
}
for(char c = 'A'; c <= 'Z';c++) { // For capital letters
chars[i++] = c;
}
int numberOfCodes = 0;
String code = "";
while (numberOfCodes < 1) { // Enter how much you want to generate at one time
int numChars = 8; // Enter how many digits you want in your password
for(i = 0; i < numChars; i++) {
char c = chars[(int)(Math.random() * chars.length)];
code = code + c;
}
System.out.println("Code is:" + code);
}
其他回答
根据您的要求更改字符串字符。字符串是不可变的。这里StringBuilder.append比字符串串联更有效。
public static String getRandomString(int length) {
final String characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJLMNOPQRSTUVWXYZ1234567890!@#$%^&*()_+";
StringBuilder result = new StringBuilder();
while(length > 0) {
Random rand = new Random();
result.append(characters.charAt(rand.nextInt(characters.length())));
length--;
}
return result.toString();
}
最佳随机字符串生成器方法
public class RandomStringGenerator{
private static int randomStringLength = 25 ;
private static boolean allowSpecialCharacters = true ;
private static String specialCharacters = "!@$%*-_+:";
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;
}
}
static final String AB = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static SecureRandom rnd = new SecureRandom();
String randomString(int len){
StringBuilder sb = new StringBuilder(len);
for(int i = 0; i < len; i++)
sb.append(AB.charAt(rnd.nextInt(AB.length())));
return sb.toString();
}
import java.util.Random;
public class passGen{
// Version 1.0
private static final String dCase = "abcdefghijklmnopqrstuvwxyz";
private static final String uCase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final String sChar = "!@#$%^&*";
private static final String intChar = "0123456789";
private static Random r = new Random();
private static StringBuilder pass = new StringBuilder();
public static void main (String[] args) {
System.out.println ("Generating pass...");
while (pass.length () != 16){
int rPick = r.nextInt(4);
if (rPick == 0){
int spot = r.nextInt(26);
pass.append(dCase.charAt(spot));
} else if (rPick == 1) {
int spot = r.nextInt(26);
pass.append(uCase.charAt(spot));
} else if (rPick == 2) {
int spot = r.nextInt(8);
pass.append(sChar.charAt(spot));
} else {
int spot = r.nextInt(10);
pass.append(intChar.charAt(spot));
}
}
System.out.println ("Generated Pass: " + pass.toString());
}
}
这只是将密码添加到字符串中。。。是的,效果很好。过来看。。。这很简单;我写的。
Java 8中的另一种选择是:
static final Random random = new Random(); // Or SecureRandom
static final int startChar = (int) '!';
static final int endChar = (int) '~';
static String randomString(final int maxLength) {
final int length = random.nextInt(maxLength + 1);
return random.ints(length, startChar, endChar + 1)
.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
.toString();
}