【雲星資料---Apache Flink實戰系列(精品版)】:Apache Flink高階特性與高階應用015-Flink中廣播變數和分散式快取001
阿新 • • 發佈:2019-02-12
1.flink中的廣播變數
flink支援將變數廣播到worker上,以供程式運算使用。
執行程式
package code.book.batch.sinksource.scala
import java.util
import org.apache.flink.api.common.functions.RichMapFunction
import org.apache.flink.api.scala.{DataSet, ExecutionEnvironment, _}
import org.apache.flink.configuration.Configuration
object BroadcastVariables001 {
def main(args: Array[String]): Unit = {
val env = ExecutionEnvironment.getExecutionEnvironment
//1.準備工人資料(用於map)
case class Worker(name: String, salaryPerMonth: Double)
val workers: DataSet[Worker] = env.fromElements(
Worker("zhagnsan", 1356.67),
Worker("lisi" , 1476.67)
)
//2準備統計資料(用於廣播,通過withBroadcastSet進行廣播)
case class Count(name: String, month: Int)
val counts: DataSet[Count] = env.fromElements(
Count("zhagnsan", 4),
Count("lisi", 5)
)
//3.使用map資料和廣播資料進行計算
workers.map(new RichMapFunction[Worker, Worker] {
private var cwork: util.List[Count] = null
override def open(parameters: Configuration): Unit = {
super.open(parameters)
// 3.1 訪問廣播資料
cwork = getRuntimeContext.getBroadcastVariable[Count]("countWorkInfo")
}
override def map(w: Worker): Worker = {
//3.2解析廣播資料
var i = 0
while (i < cwork.size()) {
val c = cwork.get(i)
i += 1
if (c.name.equalsIgnoreCase(w.name)) {
//有相應的資訊的返回值
return Worker(w.name, w.salaryPerMonth * c.month)
}
}
//無相應的資訊的返回值
Worker("###", 0)
}
}).withBroadcastSet(counts, "countWorkInfo").print()
}
}
執行效果
Worker(zhagnsan,5426.68)
Worker(lisi,7383.35)