spark 学习

     spark,又一个传说中的分布式实现,详情:http://spark-project.org/,

安装这里就不写了，因为网上已有中文介绍，这里主要是介绍一下入门，和hadoop一样，学习的时候，首先学习spark提供的字符统计例子：javaWordCount

原始代码如下：

import scala.Tuple2;
import spark.api.java.JavaPairRDD;
import spark.api.java.JavaRDD;
import spark.api.java.JavaSparkContext;
import spark.api.java.function.FlatMapFunction;
import spark.api.java.function.Function2;
import spark.api.java.function.PairFunction;

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

public class JavaWordCount {
  public static void main(String[] args) throws Exception {
    if (args.length < 2) {
      System.err.println("Usage: JavaWordCount <master> <file>");
      System.exit(1);
    }

    JavaSparkContext ctx = new JavaSparkContext(args[0], "JavaWordCount",
        System.getenv("SPARK_HOME"), System.getenv("SPARK_EXAMPLES_JAR"));
    JavaRDD<String> lines = ctx.textFile(args[1], 1);

    JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {
      public Iterable<String> call(String s) {
        return Arrays.asList(s.split(" "));
      }
    });
    
    JavaPairRDD<String, Integer> ones = words.map(new PairFunction<String, String, Integer>() {
      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>() {
      public Integer call(Integer i1, Integer i2) {
        return i1 + i2;
      }
    });

    List<Tuple2<String, Integer>> output = counts.collect();
    for (Tuple2 tuple : output) {
      System.out.println(tuple._1 + ": " + tuple._2);
    }
    System.exit(0);
  }
}

  运行： ./run spark/examples/JavaWordCount  local input.txt
 local：不解析，自己查

input.txt:文件类容

Hello World Bye World goole

 运行的结果和haddoop中运行的JavaWordCount  一样

 

goole: 1
World: 2
Hello: 1
Bye: 1

 

 

 

 

 

评论

3 楼 wenzhiyinghen 2015-11-12  

2 楼 minn84 2013-05-18  

1 楼 damoqiongqiu 2013-05-18  

呃，还以为是Flex