使用 guage 监控 map 的 size

io.micrometer.core.instrument.Metrics


@Nullable
public static <T> T gauge(String name, T obj, ToDoubleFunction<T> valueFunction) {
    return globalRegistry.gauge(name, obj, valueFunction);
}

Map<String,String> data = new ConcurrentHashMap<>();
Metrics.gauge("guageDataMapSize", data, Map::size);
Metrics.gauge("guageDataMapSize2", data, XXX::mapsizeStatic);
        
private static int mapsizeStatic(Map map) {
    return map.size();
}       

/actuator/prometheus

guageDataMapSize 5.0
guageDataMapSize2 5.0




完整代码
https://gitee.com/dyyx/springboothello/blob/master/src/main/java/demo/controller/GuageController.java