在排序前确定列表不为空

graph-web/src/main/java/org/diagbot/graphWeb/work/GraphCalculate.java

@@ -121,23 +121,23 @@ public class GraphCalculate {
         String name;
 
         try {
-            for (FeatureRate item:set) {
-                name = item.getFeatureName();
-                items.put(name, item);
-                if (sortval.get(name) == null) {
-                    sortval.put(name, "1");
+            if (set != null && set.size() > 0) {
+                for (FeatureRate item : set) {
+                    name = item.getFeatureName();
+                    items.put(name, item);
+                    if (sortval.get(name) == null) {
+                        sortval.put(name, "1");
+                    } else {
+                        sortval.put(name, String.valueOf(Integer.parseInt(sortval.get(name)) + 1));
+                    }
                 }
-                else {
-                    sortval.put(name, String.valueOf(Integer.parseInt(sortval.get(name))+1));
-                }
-            }
 
-            sortval = sortMapByValue(sortval);
+                sortval = sortMapByValue(sortval);
 
-            for (String key:sortval.keySet()) {
-                frlist.add(items.get(key));
+                for (String key : sortval.keySet()) {
+                    frlist.add(items.get(key));
+                }
             }
-
         }
         catch (Exception ex) {
             ex.printStackTrace();