原始文件baidu.log内容:

hello   world   spark   hadoop  hive    223.104.18.110  v1.go2yd.com    17168
world   spark   hello   mysql   sqoop   113.101.75.194  v2.go2yd.com    17222
spark   hello   mysql   hive    world   27.17.127.135   v2.go2yd.com    1556
......
......

需求一：求每个域名的流量
步骤：
1）获取到日志中每条记录的域名和流量
2）按照域名进行分组并求流量的和

object test {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setAppName("test").setMaster("local[2]")
    val sc = new SparkContext(sparkConf)
    val lines = sc.textFile("file:///E:/BigDataSoftware/data/baidu.log")

    val splits = lines.map(x=> {
         val tmp = x.split("\t")
         (tmp(6),tmp(7).toLong)  //取出域名和流量两列，并注意将流量转成Long类型，不然会变成字符串相加
       })
    val results = splits.reduceByKey(_+_)
    results.take(10).foreach(println)
    
sc.stop()
  }
}

如果流量数据中有字符串等脏数据时，toLong报错导致任务失败，报错如下

java.lang.NumberFormatException: For input string: "10701str"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Long.parseLong(Long.java:589)
    at java.lang.Long.parseLong(Long.java:631)
    at scala.collection.immutable.StringLike$class.toLong(StringLike.scala:276)
    at scala.collection.immutable.StringOps.toLong(StringOps.scala:29)
    at www.ruozedata.test$$anonfun$2.apply(test.scala:20)
.......

解决办法：加入一个判断

object test {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setAppName("test").setMaster("local[2]")
    val sc = new SparkContext(sparkConf)
    val lines = sc.textFile("file:///E:/BigDataSoftware/data/baidu.log")
  
  val splits = lines.map(x=> {
      val tmp = x.split("\t")
      var traffic = 0L
      try {
        traffic = tmp(7).toLong
      } catch {
        case e:Exception => traffic = 0L
      }
      (tmp(6),traffic)
    })
    val results = splits.reduceByKey(_+_)
    results.take(10).foreach(println)
    
sc.stop()
  }
}

输出结果：
------------------------------------------------
(v2.go2yd.com,38034)
(v4.go2yd.com,31969)
(v3.go2yd.com,44598)
(v1.go2yd.com,77995)

但是发现，有一条带空格的数据没有被算进去，损失一条数据，加个trim即可解决

object test {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setAppName("test").setMaster("local[2]")
    val sc = new SparkContext(sparkConf)
    val lines = sc.textFile("file:///E:/BigDataSoftware/data/baidu.log")

    val splits = lines.map(x=> {
      val tmp = x.split("\t")
      var traffic = 0L
      try {
        traffic = tmp(7).trim.toLong
      } catch {
        case e:Exception => traffic = 0L
      }
      (tmp(6),traffic)
    })
    val results = splits.reduceByKey(_+_)
    results.take(10).foreach(println)
    
sc.stop()
  }
}

输出结果：
------------------------------------------------
(v2.go2yd.com,38034)
(v4.go2yd.com,31969)
(v3.go2yd.com,51784)
(v1.go2yd.com,77995)

最后一条的流量加进来了