Fix npe two streams & fix joinwindow's production donot be conducted by mainpipeline's following stages (apache#104)

* fix NPE in two streams case

* init otherPipeline first to avoid config be overwrote, then join window's production will be conduct by mainPipeline's following stages

Author: lizhiboo

rocketmq-streams-clients/src/main/java/org/apache/rocketmq/streams/client/DataStreamAction.java

@@ -99,14 +99,17 @@ protected void start(boolean isAsync) {
         }
 
         ConfigurableComponent configurableComponent = ComponentCreator.getComponent(mainPipelineBuilder.getPipelineNameSpace(), ConfigurableComponent.class, kvs);
-        ChainPipeline pipeline = this.mainPipelineBuilder.build(configurableComponent.getService());
-        pipeline.startChannel();
+
         if (this.otherPipelineBuilders != null) {
             for (PipelineBuilder builder : otherPipelineBuilders) {
                 ChainPipeline otherPipeline = builder.build(configurableComponent.getService());
                 otherPipeline.startChannel();
             }
         }
+
+        ChainPipeline pipeline = this.mainPipelineBuilder.build(configurableComponent.getService());
+        pipeline.startChannel();
+
         if (isAsync) {
             return;
         }

rocketmq-streams-clients/src/main/java/org/apache/rocketmq/streams/client/source/DataStreamSource.java

@@ -107,7 +107,7 @@ public DataStream fromRocketmq(String topic, String groupName, String tags, bool
         rocketMQSource.setJsonData(isJson);
         rocketMQSource.setNamesrvAddr(namesrvAddress);
         this.mainPipelineBuilder.setSource(rocketMQSource);
-        return new DataStream(this.mainPipelineBuilder, null);
+        return new DataStream(this.mainPipelineBuilder, this.otherPipelineBuilders, null);
     }
 
     public DataStream fromMultipleDB(String url, String userName, String password, String tablePattern) {