报表缓存Key优化，支持以时间为粒度缓存；

xxl-job-admin/src/main/java/com/xxl/job/admin/core/util/LocalCacheUtil.java

      * @return
      */
     public static boolean set(String key, Object val, long cacheTime){
+
+        // clean timeout cache, before set new cache (avoid cache too much)
+        cleanTimeutCache();
+
+        // set new cache
         if (StringUtils.isBlank(key)) {
             return false;
         }
         }
     }
 
+    /**
+     * clean timeout cache
+     *
+     * @return
+     */
+    public static boolean cleanTimeutCache(){
+        if (!cacheRepository.keySet().isEmpty()) {
+            for (String key: cacheRepository.keySet()) {
+                LocalCacheData localCacheData = cacheRepository.get(key);
+                if (localCacheData!=null && System.currentTimeMillis()>=localCacheData.getTimeoutTime()) {
+                    cacheRepository.remove(key);
+                }
+            }
+        }
+        return true;
+    }
+
 }

xxl-job-admin/src/main/java/com/xxl/job/admin/service/impl/XxlJobServiceImpl.java

 	@Override
 	public ReturnT<Map<String, Object>> triggerChartDate(Date startDate, Date endDate) {
 		// get cache
-		Map<String, Object> triggerChartDateCache = (Map<String, Object>) LocalCacheUtil.get(TRIGGER_CHART_DATA_CACHE);
+		String cacheKey = TRIGGER_CHART_DATA_CACHE + "_" + startDate.getTime() + "_" + endDate.getTime();
+		Map<String, Object> triggerChartDateCache = (Map<String, Object>) LocalCacheUtil.get(cacheKey);
 		if (triggerChartDateCache != null) {
 			return new ReturnT<Map<String, Object>>(triggerChartDateCache);
 		}
 		result.put("triggerCountFailTotal", triggerCountFailTotal);
 
 		// set cache
-		LocalCacheUtil.set(TRIGGER_CHART_DATA_CACHE, result, 60*1000);     // cache 60s
+		LocalCacheUtil.set(cacheKey, result, 60*1000);     // cache 60s
 
 		return new ReturnT<Map<String, Object>>(result);
 	}