java.security.SecureRandom 类生产强随机数
java.util.Random 只能生成伪随机数
/**
* 取得指定长度的随机数* @param length 长度
* @return
*/
public static String getRandomNumbers(int length) {
String chose = "123456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
char ran[] = new char[length];
char temp;
Random rand = new Random();
for (int i = 0; i < length; i++) {
temp = chose.charAt(rand.nextInt(chose.length()));
ran[i] = temp;
}
String randomString = String.valueOf(ran);
return randomString;
}