public static String getRandomString(int length) {
String base = "abcdefghijklmnopqrstuvwxyz0123456789";
SecureRandom random = new SecureRandom();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
int number = random.nextInt(base.length());
sb.append(base.charAt(number));
}
return sb.toString();
}
字符串拼接的效率问题:
append的效率最高.
str = str + "a";
上面的实现机制是:str = new StringBuilder(str).append("JTZen9").toString();