如何计算java中String中字符的出现次数

Question

有人能告诉我,我怎么能做一个if子句,说我经常在这个String中使用十进制分隔符.

即:1234,56,789

Answer 1

String number = "1234,56,789";
int commaCount = number.replaceAll("[^,]*", "").length();

Answer 2

很简单:

String number = "1234,56,789";
int count = 0;
for (int i = 0; i < number.length(); i++)
    if (number.charAt(i) == ',')
        count++;
// count holds the number of ',' found