Java生成生成密码类

import java.util.Date;
import java.util.Random;

public class PasswordUtil {

public final static String[] word = {
"a", "b", "c", "d", "e", "f", "g",
"h", "j", "k", "m", "n",
"p", "q", "r", "s", "t",
"u", "v", "w", "x", "y", "z",
"A", "B", "C", "D", "E", "F", "G",
"H", "J", "K", "M", "N",
"P", "Q", "R", "S", "T",
"U", "V", "W", "X", "Y", "Z"
};

public final static String[] num = {
"2", "3", "4", "5", "6", "7", "8", "9"
};

public static String randomPassword() {
StringBuffer stringBuffer = new StringBuffer();
Random random = new Random(new Date().getTime());
boolean flag = false;
int length = random.nextInt(3) + 8;
for (int i = 0; i < length; i++) {
if (flag) {
stringBuffer.append(num[random.nextInt(num.length)]);
} else {
stringBuffer.append(word[random.nextInt(word.length)]);
}
flag = !flag;
}
return stringBuffer.toString();
}


public static void main(String[] args) throws Exception {
System.out.println(randomPassword());
Thread.sleep(100);
System.out.println(randomPassword());
Thread.sleep(100);
System.out.println(randomPassword());
}
}