packagecom.qwer.mapreduce.wordcount;importjava.io.IOException;importorg.apache.hadoop.conf.Configuration;importorg.apache.hadoop.fs.Path;importorg.apache.hadoop.io.IntWritable;importorg.apache.hadoop.io.Text;importorg.apache.hadoop.mapreduce.Job;importorg.apache.hadoop.mapreduce.lib.input.FileInputFormat...
importorg.apache.hadoop.io.LongWritable;importorg.apache.hadoop.io.Text;importorg.apache.hadoop.mapreduce.Mapper;importjava.io.IOException;publicclassWordCountMapperextendsMapper<LongWritable,Text,Text,LongWritable>{privatefinalstaticLongWritableone=newLongWritable(1);privateTextword=newText();@Overrideprotectedv...
在使用 MapReduce 框架进行数据处理的过程中,也会涉及到从多个数据集读取数据,进行join关联的操作,只不过此时需要使用 java 代码并且根据 MapReduce 的编程规范进行业务的实现。 但是由于 MapReduce 的分布式设计理念的特殊性,因此对于 MapReduce 实现 join 操作具备了一定的特殊性。特殊主要体现在:究竟...
packageicu.wzk.demo02;importorg.apache.hadoop.io.IntWritable;importorg.apache.hadoop.io.LongWritable;importorg.apache.hadoop.io.Text;importorg.apache.hadoop.mapreduce.Mapper;importjava.io.IOException;publicclassWordCountMapperextendsMapper<LongWritable,Text,Text,IntWritable>{Textk=newText();IntWritablev=new...
我们在博客《Hadoop: 单词计数(Word Count)的MapReduce实现 》中学习了如何用Hadoop-MapReduce实现单词计数,现在我们来看如何用Spark来实现同样的功能。 2. Spark的MapReudce原理 Spark框架也是MapReduce-like模型,采用“分治-聚合”策略来对数据分布进行分布并行处理。不过该框架相比Hadoop-MapReduce,具有以下两个特点:...
类实现了读写hadoop configuration对象的规范* ToolRunner.run静态方法辅助完成客户运行mapreduce初始化提交job并等等结果*/publicclassWordCountextendsConfiguredimplementsTool{/*** mapreduce 程序入口* @param args*/publicstaticvoidmain(String[]args)throwsException{intflag=ToolRunner.run(newWordCount(),args);System....
package com.hadoop.testHadoop; import java.io.IOException; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Mapper; //4个泛型中,前两个是指定mapper输入数据的类型,KEYIN是输入的key的类型,VALUEIN是输入的value的类型 ...
import org.apache.hadoop.mapreduce.Job;import java.io.IOException;public class WordCountDriver {public static void main(String[] args) throws IOException, InterruptedException, ClassNotFoundException {// String inputPath = args[0];// String outputPath = args[1];// === 测试 ===String input...
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import java.io.IOException; import java.util.StringTokenizer; public class WordCount { public static class TokenizerMapper extends Mapper<LongWritable, Text, Text, IntWritable> {
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.GenericOptionsParser; public class WordCount { public static class TokenizerMapper extends Mapper private final static IntWritable one = new IntWritable(1); private Text word = new Text(); public void map...