修正cache preparedStatement的问题

git-svn-id: http://code.alibabatech.com/svn/druid/trunk@931 b9813039-fb51-4c41-a8b9-e21c2acb5095

src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java

@@ -198,6 +198,10 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
     public void incrementClosedPreparedStatementCount() {
         closedPreparedStatementCount.incrementAndGet();
     }
+    
+    public long getClosedPreparedStatementCount() {
+        return closedPreparedStatementCount.get();
+    }
 
     public void incrementPreparedStatementCount() {
         preparedStatementCount.incrementAndGet();