List<String> splitByCharacter(String input) {
        List<String> parts = new ArrayList<>();
        int length = input.length();
        int start = 0;

        for (int i = 0; i < length; i++) {
            if (input.charAt(i) == '/') {
                if (i == 0) {
                    start = i + 1;
                    continue;
                }
                parts.add(input.substring(start, i));
                start = i + 1;
            }
        }

        // Add the last part if necessary
        if (start < length) {
            parts.add(input.substring(start));
        }

        return parts;
    }
The pattern is split by /, and each token is a node in the tree. Each node either a literal string or "{var}"
representing a variable.

@param pattern of URIs
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/config/group/uri/quickmatch/PatternTree.java