public void put(String labels) {
        if (labels.startsWith(Const.LEFT_BRACE) && labels.endsWith(Const.RIGHT_BRACE)) {
            String labelsStr = labels.substring(1, labels.length() - 1);
            if (StringUtil.isNotEmpty(labelsStr)) {
                String[] labelArr = labelsStr.split(Const.COMMA);
                put(labelArr);
            }
        } else {
            //set `_` as the key and the `labels string` as the value.
            put(GENERAL_LABEL_NAME, labels);
        }
    }
Parse the labels String to a map.

@param labels the String format is {key1=value1,key2=value1}, if not match the format will use `_` as the key and
              the `labels string` as the value.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/metrics/DataLabel.java