解决实际环境中异步调用ServiceA，而ServiceA中同步调用ServiceB的时候，会出现异步属性多传递一次的问题，即Servic…

dubbo-rpc/dubbo-rpc-api/src/main/java/com/alibaba/dubbo/rpc/filter/AsyncFilter.java

@@ -0,0 +1,19 @@
+package com.alibaba.dubbo.rpc.filter;
+
+import com.alibaba.dubbo.common.Constants;
+import com.alibaba.dubbo.common.extension.Activate;
+import com.alibaba.dubbo.rpc.*;
+
+/**
+ * Author: 游锋锋
+ * Time: 2017-08-05 15:42
+ * Copyright (C) 2017 Xiamen Yaxon Networks CO.,LTD.
+ */
+@Activate(group = {Constants.PROVIDER})
+public class AsyncFilter implements Filter{
+    @Override
+    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
+        RpcContext.getContext().getAttachments().remove(Constants.ASYNC_KEY);
+        return invoker.invoke(invocation);
+    }
+}

dubbo-rpc/dubbo-rpc-api/src/main/resources/META-INF/dubbo/internal/com.alibaba.dubbo.rpc.Filter

@@ -11,4 +11,5 @@ exception=com.alibaba.dubbo.rpc.filter.ExceptionFilter
 executelimit=com.alibaba.dubbo.rpc.filter.ExecuteLimitFilter
 deprecated=com.alibaba.dubbo.rpc.filter.DeprecatedFilter
 compatible=com.alibaba.dubbo.rpc.filter.CompatibleFilter
-timeout=com.alibaba.dubbo.rpc.filter.TimeoutFilter
+timeout=com.alibaba.dubbo.rpc.filter.TimeoutFilter
+asyncFilter=com.alibaba.dubbo.rpc.filter.AsyncFilter

yaxon-fix-bug.txt

@@ -0,0 +1,6 @@
+--author:游锋锋
+--fix-bug:修复了dubbo中异步调用会多余传递一次异步属性的问题
+--fix-way:1、在dubbox\dubbo-rpc\dubbo-rpc-api\src\main\java\com\alibaba\dubbo\rpc\filter目录
+          下新增了AsyncFilter文件
+          2、并在同模块中的resource/META-INF.dubbo.internal的com.alibaba.dubbo.rpc.Filter
+          文件的末尾追加asyncFilter=com.alibaba.dubbo.rpc.filter.AsyncFilter