DUBBO-273 缺省开启每分钟心跳

git-svn-id: http://code.alibabatech.com/svn/dubbo/trunk@1282 1a56cb94-b969-4eaa-88fa-be21384802f2

dubbo-common/src/main/java/com/alibaba/dubbo/common/Constants.java

@@ -111,7 +111,7 @@ public class Constants {
 
     public static final int     DEFAULT_IDLE_TIMEOUT               = 600 * 1000;
 
-    public static final int     DEFAULT_HEARTBEAT                  = 0;
+    public static final int     DEFAULT_HEARTBEAT                  = 60 * 1000;
 
     public static final int     DEFAULT_TIMEOUT                    = 1000;