正则表达式匹配${123…456}并在Java中提取2个数字？

Question

当我知道一个字符串的格式总是${INT1...INT2}例如，“Hello${123...456}将提取123,456时，从字符串中期望2个整数的最简单简洁的方法是什么

Answer 1

我会使用带有组和反向引用的Pattern

下面是一个例子：

String input = "Hello ${123...456}, bye ${789...101112}";
//                           | escaped "$"
//                           |  | escaped "{"
//                           |  |  | first group (any number of digits)
//                           |  |  |    | 3 escaped dots
//                           |  |  |    |       | second group (same as 1st)
//                           |  |  |    |       |    | escaped "}"
Pattern p = Pattern.compile("\\$\\{(\\d+)\\.{3}(\\d+)\\}");
Matcher m = p.matcher(input);
// iterating over matcher's find for multiple matches
while (m.find()) {
    System.out.println("Found...");
    System.out.println("\t" + m.group(1));
    System.out.println("\t" + m.group(2));
}

输出

Found...
    123
    456
Found...
    789
    101112

Answer 2

final String string = "${123...456}";
final String firstPart = string.substring(string.indexOf("${") + "${".length(), string.indexOf("..."));
final String secondPart = string.substring(string.indexOf("...") + "...".length(), string.indexOf("}"));
final Integer integer = Integer.valueOf(firstPart.concat(secondPart));