生成随机密码

RandomUtils.java

private static final List<String> PWD_CHARS;

	static {
		PWD_CHARS = new ArrayList<String>();
		PWD_CHARS.add("123456789");
		PWD_CHARS.add("qwertyuipkjhgfdsazxcvbnm");
		PWD_CHARS.add("QWERTYUPLKJHGFDSAZXCVBNM");
	}

	/**
	 * 返回一个字符串和字母的随机字符串
	 *
	 * @param length 长度
	 */
	public static String randomString(int length) {
		StringBuilder sb = new StringBuilder();
		Random random = new Random();
		int size = PWD_CHARS.size();
		for (int i = 0; i < length; i++) {
			String pwdChar = PWD_CHARS.get(random.nextInt(size));
			sb.append(pwdChar.charAt(random.nextInt(pwdChar.length())));
		}
		String result = sb.toString();
		return result.matches("(?![0-9]+$)(?![a-zA-Z]+$)(?![0-9a-z]+$)" +
				"(?![0-9A-Z]+$)[0-9A-Za-z]+")
				? result : randomString(length);
	}