JAVA在特定char的第一个和最后一个出现之间获取字符串

Question

Assuming I have this string:

mystring
{
    a : 1
    b : 2
    c : { e :f}
    d : x
}

How do I do it such that I will get only the string between the first opening curly-bracket and the last opening curly bracket

As such :

    a : 1
    b : 2
    c : { e :f}
    d : x

Answer 1

By default the search is done greedily. You need to find your first { non-greedily ( .*? ), while the capture should be done again greedily ( .* ):

".*?\{(.*)\}.*"

The full code would be:

String s = // your input string
Pattern p = Pattern.compile(".*?\\{(.*)\\}.*");
Matcher m = p.matcher(s);
if (m.find()) {
    System.out.println(m.group(1));
}

You could do the same thing without regex, too, using plain String methods:

int start = s.indexOf("{") + 1;
int end = s.lastIndexOf("}");
if (start > -1 && end > start) {
    System.out.println(s.substring(start, end));
}

Answer 2

你可以简单地使用带有参数indexOf('{')和lastIndexOf('}') substring()方法，如下所示：

yourString=yourString.substring(indexOf('{'),lastIndexOf('}'));