txlcn-tracing/src/main/java/com/codingapi/txlcn/tracing/TracingContext.java
public String appMapString() {
        if (hasGroup()) {
            String appMap = Optional.ofNullable(this.fields.get(TracingConstants.APP_MAP)).orElse("");
            log.debug("App map: {}", appMap);
            return appMap;
        }
        raiseNonGroupException();
        return "{}";
    }
public String appMapString() {
        if (hasGroup()) {
            String appMap = Optional.ofNullable(this.fields.get(TracingConstants.APP_MAP)).orElse("");
            log.debug("App map: {}", appMap);
            return appMap;
        }
        raiseNonGroupException();
        return "{}";
    }
String Type App map.

@return appMap