Question

Java：正则表达式求解，前四位为任意字符，后四位为数字，该如何判断呢

合法
BSBS0012
BS001122
非法
BSBSBSBS

Answer 1

public static void main(String[] args) {
try {
List<String> list=null;
list.get(0);
} catch (NullPointerException e) {
System.out.println(e);
}

}

Answer 2

String reg = "^.{4}\\d{4}$";
String str = "";
str.matches(reg);
回答完毕~~即可

Answer 3

^.{4}[0-9]{4}$