flink batch dataset的示例代码

package hgs.flink_lesson

import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.streaming.api.scala._
import org.apache.flink.api.scala.ExecutionEnvironment
import org.apache.flink.core.fs.FileSystem.WriteMode
import org.apache.flink.api.common.accumulators.Accumulator
import org.apache.flink.api.common.accumulators.IntCounter
import scala.collection.immutable.List
import scala.collection.mutable.ListBuffer
import scala.collection.immutable.HashMap

//import StreamExecutionEnvironment.class
object WordCount {
  def main(args: Array[String]): Unit = {
     val params = ParameterTool.fromArgs(args)
     //1.获得一个执行环境,如果是Streaming则换成StreamExecutionEnvironment
     val env = ExecutionEnvironment.getExecutionEnvironment
     //这样会得到当前环境下的配置
     env.getConfig.setGlobalJobParameters(params)
     println(params.get("input"))
      println(params.get("output"))

     val text = if(params.has("input")){
       //2.加载或者创建初始化数据
       env.readTextFile(params.get("input"))
     }else{
       println("Please specify the input file directory.")
       return
     }
     
     println("lines "+text.count())
     val ac =   new IntCounter
     //3.在数据上指明操作类型
     val counts = text.flatMap{ _.toLowerCase().split("\\W+").filter{_.nonEmpty}}
           //这里与spark的算子的groupBy有点不同，这边要用数组类似的下标来确定根据什么进行分组
           .map{(_,1)}.groupBy(0).reduceGroup(it=>{
                                               
                                                
                                               val tuple = it.next()
                                               var cnt = tuple._2 
                                               val ch = tuple._1
                                               while(it.hasNext){
                                                 cnt= cnt+it.next()._2
                                               }
                                               (ch,cnt)})
      //指明计算后的数据结果放到哪个位置
      //4.counts.print()
      counts.writeAsCsv("file:/d:/re.txt", "\n", " ",WriteMode.OVERWRITE)
      //5.触发程序执行
      env.execute("Scala WordCount Example")
      //     

  }
}