java實現spark常用算子之SortByKey

import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.VoidFunction;
import scala.Tuple2;

import java.util.Arrays;
import java.util.List;

/**
 * sortbykey([ascending],[numTasks]) 算子：
 * 根據key進行排序操作
 * 第一個參數為true,則為升序，反之為降序
 * 第二個參數決定執行的task數目
 *
 */
public class SortByKeyOperator {
 public static void main(String[] args){
 SparkConf conf = new SparkConf().setMaster("local").setAppName("sortByKey");
 JavaSparkContext sc = new JavaSparkContext(conf);

 List<Tuple2<String,Integer>> list = Arrays.asList(
 new Tuple2<String,Integer>("w1",1),
 new Tuple2<String,Integer>("w2",2),
 new Tuple2<String,Integer>("w3",3),
 new Tuple2<String,Integer>("w2",22),
 new Tuple2<String,Integer>("w1",11)
 );

 JavaPairRDD<String,Integer> pairRdd = sc.parallelizePairs(list);

 JavaPairRDD<String,Integer> result = pairRdd.sortByKey(true,2);

 result.foreach(new VoidFunction<Tuple2<String, Integer>>() {
 @Override
 public void call(Tuple2<String, Integer> stringIntegerTuple2) throws Exception {
 System.err.println(stringIntegerTuple2._1+":"+stringIntegerTuple2._2);
 }
 });

 }
}

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