正则替换

/**
 * 数字替换，适当位置加-
 */
public static void main(String[] args) {
    String regex = "^(\\d{2})(\\d)(\\d{4})(\\d{4})(\\d)$";
    String test = "121123412344";
    System.out.println("是否匹配(true/false)：" + Pattern.compile(regex).matcher(test).matches());
    System.out.println(test.replaceAll(regex, "$1-$2-$3-$4-$5"));
}

输出：

是否匹配(true/false)：true
12-1-1234-1234-4