### Question:
RegexUtil { public static boolean isVehicleLicence(String license) { if (license == null) return false; return license.matches("^(([京津沪渝冀豫云辽黑湘皖鲁新苏浙赣鄂桂甘晋蒙陕吉闽贵粤青藏川宁琼使领][A-Z](([0-9]{5}[DF])|([DF]([A-HJ-NP-Z0-9])[0-9]{4})))|([京津沪渝冀豫云辽黑湘皖鲁新苏浙赣鄂桂甘晋蒙陕吉闽贵粤青藏川宁琼使领][A-Z][A-HJ-NP-Z0-9]{4}[A-HJ-NP-Z0-9挂学警港澳使领]))$"); }  static boolean isIdentityNumber(String num); static boolean isCellphoneNumber(String num); static boolean isCellphoneNumber(String num, boolean virtual); static boolean isPhoneNumber(String num); static boolean isAuthCode(String num); static boolean isAuthCode(String num, int min, int max); static boolean isName(String name); static boolean isVehicleLicence(String license); static boolean isEmail(String email); static boolean isBankCard(String card); static boolean isLowerMoney(String money); static boolean isInteger(String integer, long min, long max); static boolean isPassword(String password); static boolean isComplexPassword(String password); static boolean isIpAddress(String address); static boolean isIp4Address(String address); static boolean isIp6Address(String address);  }### Answer:
@Test public void isVehicleLicence() { assertTrue(RegexUtil.isVehicleLicence("川A12345")); assertTrue(RegexUtil.isVehicleLicence("川A54374D")); }