Java如何实现字符串每隔4位加空格

String bankCard = authStatus.getBankCard();
String bankCard = "1234567890";
String regex = "(.{4})";
bankCard = bankCard.replaceAll(regex,"$1 ");
System.out.println(bankCard);
 
// 打印1234 5678 90

String bankCard1 = "333434343443434344";
char[] bankArray = bankCard1.toCharArray();
String bankString = "";
for(int i=0;i<bankArray.length;i++){
    if(i%4==0 && i>0){
bankString +=" ";
    }
    bankString += bankArray[i];
}
System.out.println(bankString);
     
// 打印结果3334 3434 3443 4343 44

String str = "123456789013";
String regex = "(.{4})";
String result = str.replaceAll(regex, "$1,");
LogUtil.e("result:" + result);