spark读hdfs文件实现wordcount并将结果存回hdfs

package iie.udps.example.operator.spark;
 
import scala.Tuple2;
 
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.Function;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFunction;
import java.util.Arrays;
import java.util.regex.Pattern;
 
/**
 * 利用Spark框架读取HDFS文件，实现WordCount示例
 * 
 * 执行命令：spark-submit --class iie.hadoop.hcatalog.TextFileSparkTest --master
 * yarn-cluster /tmp/sparkTest.jar hdfs://192.168.8.101/test/words
 * hdfs://192.168.8.101/test/spark/out
 * 
 * @author xiaodongfang
 *
 */
public final class TextFileSparkTest {
    private static final Pattern SPACE = Pattern.compile(" ");
 
    @SuppressWarnings("serial")
    public static void main(String[] args) throws Exception {
 
        if (args.length < 2) {
            System.err.println("Usage: JavaWordCount <file>");
            System.exit(1);
        }
        String inputSparkFile = args[0];
        String outputSparkFile = args[1];
 
        SparkConf sparkConf = new SparkConf().setAppName("SparkWordCount");
        JavaSparkContext ctx = new JavaSparkContext(sparkConf);
        JavaRDD<String> lines = ctx.textFile(inputSparkFile, 1);
        JavaRDD<String> words = lines
                .flatMap(new FlatMapFunction<String, String>() {
                    @Override
                    public Iterable<String> call(String s) {
                        return Arrays.asList(SPACE.split(s));
                    }
                });
 
        JavaPairRDD<String, Integer> ones = words
                .mapToPair(new PairFunction<String, String, Integer>() {
 
                    @Override
                    public Tuple2<String, Integer> call(String s) {
                        return new Tuple2<String, Integer>(s, 1);
                    }
                });
         
 
        JavaPairRDD<String, Integer> counts = ones
                .reduceByKey(new Function2<Integer, Integer, Integer>() {
                    @Override
                    public Integer call(Integer i1, Integer i2) {
                        return i1 + i2;
                    }
                });
 
        counts.map(new Function<Tuple2<String, Integer>, String>() {
            @Override
            public String call(Tuple2<String, Integer> arg0) throws Exception {
                return arg0._1.toUpperCase() + ": " + arg0._2;
            }
        }).saveAsTextFile(outputSparkFile);
 
        ctx.stop();
    }
}