spark的做算子统计的Java代码（在Linux系统集群式运行）

package com.spark.study.core;

import java.util.Arrays;
import java.util.Iterator;

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.PairFunction;
import org.apache.spark.api.java.function.VoidFunction;

import scala.Tuple2;

/**
 * 将java开发的wordcount程序部署到spark集群上运行
 * @author Administrator
 *
 */
public class WordCountCluster {
   
   public static void main(String[] args) {
      // 如果要在spark集群上运行，需要修改的，只有两个地方
      // 第一，将SparkConf的setMaster()方法给删掉，默认它自己会去连接
      // 第二，我们针对的不是本地文件了，修改为hadoop hdfs上的真正的存储大数据的文件
      
      // 实际执行步骤：
      // 1、将spark.txt文件上传到hdfs上去
      // 2、使用我们最早在pom.xml里配置的maven插件，对spark工程进行打包
      // 3、将打包后的spark工程jar包，上传到机器上执行
      // 4、编写spark-submit脚本
      // 5、执行spark-submit脚本，提交spark应用到集群执行
      
      SparkConf conf = new SparkConf()
            .setAppName("WordCountCluster");  
      
      JavaSparkContext sc = new JavaSparkContext(conf);

      JavaRDD<String> lines = sc.textFile("hdfs://node1:9000/spark.txt");
      
      JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {       
         private static final long serialVersionUID = 1L;  
         @Override
         public Iterator<String> call(String line) throws Exception {
            return Arrays.asList(line.split(" ")).iterator();
         }       
      })；
      JavaPairRDD<String, Integer> pairs = words.mapToPair(
            new PairFunction<String, String, Integer>() {
               private static final long serialVersionUID = 1L;      
               @Override
               public Tuple2<String, Integer> call(String word) throws Exception {
                  return new Tuple2<String, Integer>(word, 1);
               }              
            });
      
      JavaPairRDD<String, Integer> wordCounts = pairs.reduceByKey(          
            new Function2<Integer, Integer, Integer>() {               
               private static final long serialVersionUID = 1L;     
               @Override
               public Integer call(Integer v1, Integer v2) throws Exception {
                  return v1 + v2;
               }               
            });
      wordCounts.foreach(new VoidFunction<Tuple2<String,Integer>>() {         
         private static final long serialVersionUID = 1L;        
　　　　　　@Override
         public void call(Tuple2<String, Integer> wordCount) throws Exception {
            System.out.println(wordCount._1 + " appeared " + wordCount._2 + " times.");
         }         
      });      
      sc.close();
   }   
}