首页 > 大数据 > 数据分析 > 第一次尝试使用java写spark
package hgs.spark;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFlatMapFunction;
import scala.Tuple2;
public class JavaRDDWC {
public static void main(String[] args) {
//System.setProperty("HADOOP_USER_NAME","administrator");
//需要hadoop windows的winutils.exe
System.setProperty("hadoop.home.dir", "D:\\hadoop-2.7.1");
SparkConf conf = new SparkConf().setAppName("javawc").setMaster("local[2]");
@SuppressWarnings("resource")
JavaSparkContext context = new JavaSparkContext(conf);
JavaRDD<String> rdd = context.textFile("D:\\test.txt");
//split成数组
JavaRDD<String[]> rdd1 = rdd.map(s -> s.split(","));
//只有pairrdd才可以reducebykey
JavaPairRDD<String, Integer> rdd2 = rdd1.flatMapToPair(new flatMapFunc());
JavaPairRDD<String, Integer> rdd3 = rdd2.reduceByKey(new reducefunc());
rdd3.saveAsTextFile("D:\\fff");
context.stop();
}
}
class reducefunc implements Function2<Integer, Integer, Integer>{
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
public Integer call(Integer v1, Integer v2) throws Exception {
return v1+v2;
}
}
class flatmf implements FlatMapFunction<String[], String>{
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
public Iterator<String> call(String[] t) throws Exception {
List<String> list = new ArrayList<>();
for(String str : t) {
list.add(str);
}
return list.iterator();
}
}
class flatMapFunc implements PairFlatMapFunction<String[], String, Integer>{
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
public Iterator<Tuple2<String, Integer>> call(String[] t) throws Exception {
List<Tuple2<String,Integer>> list = new ArrayList<>();
for(String str : t) {
list.add(new Tuple2<String, Integer>(str, 1));
}
return list.iterator();
}
}
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