Merge pull request lw-lin#21 from wongxingjun/xj-branch

Fix typo: "transformation" -> "output"

Spark Streaming 源码解析系列/0.1 Spark Streaming 实现思路与模块概述.md

@@ -294,7 +294,7 @@ val lines = ssc.socketTextStream("localhost", 9999)
 val words = lines.flatMap(_.split(" "))      // DStream transformation
 val pairs = words.map(word => (word, 1))     // DStream transformation
 val wordCounts = pairs.reduceByKey(_ + _)    // DStream transformation
-wordCounts.print()                           // DStream transformation
+wordCounts.print()                           // DStream output
 // 上面 4 行利用 DStream transformation 构造出了 lines -> words -> pairs -> wordCounts -> .print() 这样一个 DStreamGraph
 // 但注意，到目前是定义好了产生数据的 SocketReceiver，以及一个 DStreamGraph，这些都是静态的