{"id":1716,"date":"2018-10-09T15:23:15","date_gmt":"2018-10-09T07:23:15","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1716"},"modified":"2018-10-24T18:03:04","modified_gmt":"2018-10-24T10:03:04","slug":"hadoop-%e5%ad%a6%e4%b9%a0%e7%ac%94%e8%ae%b0%ef%bc%9amapreduce%e6%a1%86%e6%9e%b6%e8%af%a6%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1716","title":{"rendered":"hadoop \u5b66\u4e60\u7b14\u8bb0\uff1amapreduce\u6846\u67b6\u8be6\u89e3"},"content":{"rendered":"
\u3000\u3000\u5f00\u59cb\u804amapreduce\uff0cmapreduce\u662fhadoop\u7684\u8ba1\u7b97\u6846\u67b6\uff0c\u6211\u5b66hadoop\u662f\u4ecehive\u5f00\u59cb\u5165\u624b\uff0c\u518d\u5230hdfs\uff0c\u5f53\u6211\u5b66\u4e60hdfs\u65f6\u5019\uff0c\u5c31\u611f\u89c9\u5230hdfs\u548cmapreduce\u5173\u7cfb\u7684\u7d27\u5bc6\u3002\u8fd9\u4e2a\u53ef\u80fd\u662f\u6211\u505a\u6280\u672f\u7814\u7a76\u7684\u601d\u8def\u6709\u5173\uff0c\u6211\u5f00\u59cb\u5b66\u4e60\u67d0\u4e00\u5957\u6280\u672f\u603b\u662f\u60f3\u7740\u8fd9\u5957\u6280\u672f\u5230\u5e95\u80fd\u5e72\u4ec0\u4e48\uff0c\u53ea\u6709\u5f53\u6211\u771f\u6b63\u7406\u89e3\u4e86\u8fd9\u5957\u6280\u672f\u89e3\u51b3\u4e86\u4ec0\u4e48\u95ee\u9898\u65f6\u5019\uff0c\u6211\u540e\u7eed\u7684\u5b66\u4e60\u5c31\u80fd\u9010\u6b65\u7684\u52a0\u5feb\uff0c\u800c\u5b66\u4e60hdfs\u65f6\u5019\u6211\u5c31\u53d1\u73b0\uff0c\u8981\u7406\u89e3hadoop\u6846\u67b6\u7684\u610f\u4e49\uff0chdfs\u548cmapreduce\u662f\u5bc6\u4e0d\u53ef\u5206\uff0c\u6240\u4ee5\u5f53\u6211\u5199\u5206\u5e03\u5f0f\u6587\u4ef6\u7cfb\u7edf\u65f6\u5019\uff0c\u603b\u662f\u611f\u89c9\u81ea\u5df1\u7684\u7406\u89e3\u80a4\u6d45\uff0c\u4eca\u5929\u6211\u5f00\u59cb\u5199mapreduce\u4e86\uff0c\u4eca\u5929\u5199\u6587\u7ae0\u65f6\u5019\u6bd4\u4e0a\u5468\u8981\u8fdb\u6b65\u591a\uff0c\u4e0d\u8fc7\u5230\u5e95\u80fd\u4e0d\u80fd\u5199\u597d\u672c\u6587\u4e86\uff0c\u53ea\u6709\u8bd5\u8bd5\u518d\u8bf4\u4e86\u3002<\/div>\n
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\u3000\u3000Mapreduce<\/strong>\u521d\u6790<\/strong><\/p>\n

Mapreduce\u662f\u4e00\u4e2a\u8ba1\u7b97\u6846\u67b6\uff0c\u65e2\u7136\u662f\u505a\u8ba1\u7b97\u7684\u6846\u67b6\uff0c\u90a3\u4e48\u8868\u73b0\u5f62\u5f0f\u5c31\u662f\u6709\u4e2a\u8f93\u5165\uff08input\uff09\uff0cmapreduce\u64cd\u4f5c\u8fd9\u4e2a\u8f93\u5165\uff08input\uff09\uff0c\u901a\u8fc7\u672c\u8eab\u5b9a\u4e49\u597d\u7684\u8ba1\u7b97\u6a21\u578b\uff0c\u5f97\u5230\u4e00\u4e2a\u8f93\u51fa\uff08output\uff09\uff0c\u8fd9\u4e2a\u8f93\u51fa\u5c31\u662f\u6211\u4eec\u6240\u9700\u8981\u7684\u7ed3\u679c\u3002<\/p>\n

\u6211\u4eec\u8981\u5b66\u4e60\u7684\u5c31\u662f\u8fd9\u4e2a\u8ba1\u7b97\u6a21\u578b\u7684\u8fd0\u884c\u89c4\u5219\u3002\u5728\u8fd0\u884c\u4e00\u4e2amapreduce\u8ba1\u7b97\u4efb\u52a1\u65f6\u5019\uff0c\u4efb\u52a1\u8fc7\u7a0b\u88ab\u5206\u4e3a\u4e24\u4e2a\u9636\u6bb5\uff1amap\u9636\u6bb5\u548creduce\u9636\u6bb5\uff0c\u6bcf\u4e2a\u9636\u6bb5\u90fd\u662f\u7528\u952e\u503c\u5bf9\uff08key\/value\uff09\u4f5c\u4e3a\u8f93\u5165\uff08input\uff09\u548c\u8f93\u51fa\uff08output\uff09\u3002\u800c\u7a0b\u5e8f\u5458\u8981\u505a\u7684\u5c31\u662f\u5b9a\u4e49\u597d\u8fd9\u4e24\u4e2a\u9636\u6bb5\u7684\u51fd\u6570\uff1amap\u51fd\u6570\u548creduce\u51fd\u6570\u3002<\/p>\n

\u3000\u3000Mapreduce<\/strong>\u7684\u57fa\u7840\u5b9e\u4f8b<\/strong><\/p>\n

\u8bb2\u89e3mapreduce\u8fd0\u884c\u539f\u7406\u524d\uff0c\u9996\u5148\u6211\u4eec\u770b\u770bmapreduce\u91cc\u7684hello world\u5b9e\u4f8bWordCount,\u8fd9\u4e2a\u5b9e\u4f8b\u5728\u4efb\u4f55\u4e00\u4e2a\u7248\u672c\u7684hadoop\u5b89\u88c5\u7a0b\u5e8f\u91cc\u90fd\u4f1a\u6709\uff0c\u5927\u5bb6\u5f88\u5bb9\u6613\u627e\u5230\uff0c\u8fd9\u91cc\u6211\u8fd8\u662f\u8d34\u51fa\u4ee3\u7801\uff0c\u4fbf\u4e8e\u6211\u540e\u9762\u7684\u8bb2\u89e3\uff0c\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n

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\n\n\n\n
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\n
\/**<\/code><\/div>\n
\u00a0<\/code>* Licensed to the Apache Software Foundation (ASF) under one<\/code><\/div>\n
\u00a0<\/code>* or more contributor license agreements.\u00a0 See the NOTICE file<\/code><\/div>\n
\u00a0<\/code>* distributed with this work for additional information<\/code><\/div>\n
\u00a0<\/code>* regarding copyright ownership.\u00a0 The ASF licenses this file<\/code><\/div>\n
\u00a0<\/code>* to you under the Apache License, Version 2.0 (the<\/code><\/div>\n
\u00a0<\/code>* \"License\"); you may not use this file except in compliance<\/code><\/div>\n
\u00a0<\/code>* with the License.\u00a0 You may obtain a copy of the License at<\/code><\/div>\n
\u00a0<\/code>*<\/code><\/div>\n
\u00a0<\/code>*\u00a0\u00a0\u00a0\u00a0 http:\/\/www.apache.org\/licenses\/LICENSE-2.0<\/code><\/div>\n
\u00a0<\/code>*<\/code><\/div>\n
\u00a0<\/code>* Unless required by applicable law or agreed to in writing, software<\/code><\/div>\n
\u00a0<\/code>* distributed under the License is distributed on an \"AS IS\" BASIS,<\/code><\/div>\n
\u00a0<\/code>* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<\/code><\/div>\n
\u00a0<\/code>* See the License for the specific language governing permissions and<\/code><\/div>\n
\u00a0<\/code>* limitations under the License.<\/code><\/div>\n
\u00a0<\/code>*\/<\/code><\/div>\n
package<\/code>\u00a0org.apache.hadoop.examples;<\/code><\/div>\n
<\/div>\n
import<\/code>\u00a0java.io.IOException;<\/code><\/div>\n
import<\/code>\u00a0java.util.StringTokenizer;<\/code><\/div>\n
<\/div>\n
import<\/code>\u00a0org.apache.hadoop.conf.Configuration;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.fs.Path;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.io.IntWritable;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.io.Text;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.mapreduce.Job;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.mapreduce.Mapper;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.mapreduce.Reducer;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.mapreduce.lib.input.FileInputFormat;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;<\/code><\/div>\n
import<\/code>\u00a0org.apache.hadoop.util.GenericOptionsParser;<\/code><\/div>\n
<\/div>\n
public<\/code>\u00a0class<\/code>\u00a0WordCount {<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0<\/code>public<\/code>\u00a0static<\/code>\u00a0class<\/code>\u00a0TokenizerMapper <\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>extends<\/code>\u00a0Mapper<Object, Text, Text, IntWritable>{<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>private<\/code>\u00a0final<\/code>\u00a0static<\/code>\u00a0IntWritable one = <\/code>new<\/code>\u00a0IntWritable(<\/code>1<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>private<\/code>\u00a0Text word = <\/code>new<\/code>\u00a0Text();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>public<\/code>\u00a0void<\/code>\u00a0map(Object key, Text value, Context context<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>) <\/code>throws<\/code>\u00a0IOException, InterruptedException {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>StringTokenizer itr = <\/code>new<\/code>\u00a0StringTokenizer(value.toString());<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>while<\/code>\u00a0(itr.hasMoreTokens()) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>word.set(itr.nextToken());<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>context.write(word, one);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0<\/code>public<\/code>\u00a0static<\/code>\u00a0class<\/code>\u00a0IntSumReducer <\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>extends<\/code>\u00a0Reducer<Text,IntWritable,Text,IntWritable> {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>private<\/code>\u00a0IntWritable result = <\/code>new<\/code>\u00a0IntWritable();<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>public<\/code>\u00a0void<\/code>\u00a0reduce(Text key, Iterable<IntWritable> values, <\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>Context context<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>) <\/code>throws<\/code>\u00a0IOException, InterruptedException {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0sum = <\/code>0<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>for<\/code>\u00a0(IntWritable val : values) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>sum += val.get();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>result.set(sum);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>context.write(key, result);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0<\/code>}<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0<\/code>public<\/code>\u00a0static<\/code>\u00a0void<\/code>\u00a0main(String[] args) <\/code>throws<\/code>\u00a0Exception {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>Configuration conf = <\/code>new<\/code>\u00a0Configuration();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>String[] otherArgs = <\/code>new<\/code>\u00a0GenericOptionsParser(conf, args).getRemainingArgs();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(otherArgs.length != <\/code>2<\/code>) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>System.err.println(<\/code>\"Usage: wordcount <in> <out>\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>System.exit(<\/code>2<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>Job job = <\/code>new<\/code>\u00a0Job(conf, <\/code>\"word count\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setJarByClass(WordCount.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setMapperClass(TokenizerMapper.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setCombinerClass(IntSumReducer.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setReducerClass(IntSumReducer.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setOutputKeyClass(Text.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>job.setOutputValueClass(IntWritable.<\/code>class<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>FileInputFormat.addInputPath(job, <\/code>new<\/code>\u00a0Path(otherArgs[<\/code>0<\/code>]));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>FileOutputFormat.setOutputPath(job, <\/code>new<\/code>\u00a0Path(otherArgs[<\/code>1<\/code>]));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>System.exit(job.waitForCompletion(<\/code>true<\/code>) ? <\/code>0<\/code>\u00a0: <\/code>1<\/code>);<\/code><\/div>\n
\u00a0\u00a0<\/code>}<\/code><\/div>\n
}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n

 <\/p>\n

\u5982\u4f55\u8fd0\u884c\u5b83\uff0c\u8fd9\u91cc\u4e0d\u505a\u7d2f\u8ff0\u4e86\uff0c\u5927\u4f19\u53ef\u4ee5\u767e\u5ea6\u4e0b\uff0c\u7f51\u4e0a\u8fd9\u65b9\u9762\u7684\u8d44\u6599\u5f88\u591a\u3002\u8fd9\u91cc\u7684\u5b9e\u4f8b\u4ee3\u7801\u662f\u4f7f\u7528\u65b0\u7684api\uff0c\u5927\u5bb6\u53ef\u80fd\u5728\u5f88\u591a\u4e66\u7c4d\u91cc\u770b\u5230\u8bb2\u89e3mapreduce\u7684WordCount\u5b9e\u4f8b\u90fd\u662f\u8001\u7248\u672c\u7684api\uff0c\u8fd9\u91cc\u6211\u4e0d\u7ed9\u51fa\u8001\u7248\u672c\u7684api\uff0c\u56e0\u4e3a\u8001\u7248\u672c\u7684api\u4e0d\u592a\u5efa\u8bae\u4f7f\u7528\u4e86\uff0c\u5927\u5bb6\u505a\u5f00\u53d1\u6700\u597d\u4f7f\u7528\u65b0\u7248\u672c\u7684api\uff0c\u65b0\u7248\u672capi\u548c\u65e7\u7248\u672capi\u6709\u533a\u522b\u5728\u54ea\u91cc\uff1a<\/p>\n

    \n
  1. \u65b0\u7684api\u653e\u5728\uff1aorg.apache.hadoop.mapreduce,\u65e7\u7248api\u653e\u5728\uff1aorg.apache.hadoop.mapred<\/li>\n
  2. \u65b0\u7248api\u4f7f\u7528\u865a\u7c7b\uff0c\u800c\u65e7\u7248\u7684\u4f7f\u7528\u7684\u662f\u63a5\u53e3\uff0c\u865a\u7c7b\u66f4\u52a0\u5229\u4e8e\u6269\u5c55\uff0c\u8fd9\u4e2a\u662f\u4e00\u4e2a\u7ecf\u9a8c\uff0c\u5927\u5bb6\u53ef\u4ee5\u597d\u597d\u5b66\u4e60\u4e0bhadoop\u7684\u8fd9\u4e2a\u7ecf\u9a8c\u3002<\/li>\n<\/ol>\n

    \u5176\u4ed6\u8fd8\u6709\u5f88\u591a\u533a\u522b\uff0c\u90fd\u662f\u8bf4\u660e\u65b0\u7248\u672capi\u7684\u4f18\u52bf\uff0c\u56e0\u4e3a\u6211\u63d0\u5021\u4f7f\u7528\u65b0\u7248api\uff0c\u8fd9\u91cc\u5c31\u4e0d\u8bb2\u8fd9\u4e9b\uff0c\u56e0\u4e3a\u6ca1\u5fc5\u8981\u518d\u7528\u65e7\u7248\u672c\uff0c\u56e0\u6b64\u8fd9\u79cd\u6bd4\u8f83\u4e5f\u6ca1\u5565\u610f\u4e49\u4e86\u3002<\/p>\n

    \u4e0b\u9762\u6211\u5bf9\u4ee3\u7801\u505a\u7b80\u5355\u7684\u8bb2\u89e3\uff0c\u5927\u5bb6\u770b\u5230\u8981\u5199\u4e00\u4e2amapreduce\u7a0b\u5e8f\uff0c\u6211\u4eec\u7684\u5b9e\u73b0\u4e00\u4e2amap\u51fd\u6570\u548creduce\u51fd\u6570\u3002\u6211\u4eec\u770b\u770bmap\u7684\u65b9\u6cd5\uff1a<\/p>\n

    \n
    public void map(Object key, Text value, Context context) throws IOException, InterruptedException {\u2026}<\/pre>\n<\/div>\n
    \u8fd9\u91cc\u6709\u4e09\u4e2a\u53c2\u6570\uff0c\u524d\u9762\u4e24\u4e2aObject key, Text value\u5c31\u662f\u8f93\u5165\u7684key\u548cvalue\uff0c\u7b2c\u4e09\u4e2a\u53c2\u6570Context context\u8fd9\u662f\u53ef\u4ee5\u8bb0\u5f55\u8f93\u5165\u7684key\u548cvalue\uff0c\u4f8b\u5982\uff1acontext.write(word, one);\u6b64\u5916context\u8fd8\u4f1a\u8bb0\u5f55map\u8fd0\u7b97\u7684\u72b6\u6001\u3002<\/p>\n
    \u5bf9\u4e8ereduce\u51fd\u6570\u7684\u65b9\u6cd5\uff1a<\/p>\n
    \n
    public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {\u2026}<\/pre>\n<\/div>\n
    reduce\u51fd\u6570\u7684\u8f93\u5165\u4e5f\u662f\u4e00\u4e2akey\/value\u7684\u5f62\u5f0f\uff0c\u4e0d\u8fc7\u5b83\u7684value\u662f\u4e00\u4e2a\u8fed\u4ee3\u5668\u7684\u5f62\u5f0fIterable<IntWritable> values\uff0c\u4e5f\u5c31\u662f\u8bf4reduce\u7684\u8f93\u5165\u662f\u4e00\u4e2akey\u5bf9\u5e94\u4e00\u7ec4\u7684\u503c\u7684value\uff0creduce\u4e5f\u6709context\u548cmap\u7684context\u4f5c\u7528\u4e00\u81f4\u3002<\/p>\n
    \u81f3\u4e8e\u8ba1\u7b97\u7684\u903b\u8f91\u5c31\u662f\u7a0b\u5e8f\u5458\u81ea\u5df1\u53bb\u5b9e\u73b0\u4e86\u3002<\/p>\n
    \u4e0b\u9762\u5c31\u662fmain\u51fd\u6570\u7684\u8c03\u7528\u4e86\uff0c\u8fd9\u4e2a\u6211\u8981\u8be6\u7ec6\u8bb2\u8ff0\u4e0b\uff0c\u9996\u5148\u662f\uff1a<\/p>\n
    \n
    Configuration conf = new Configuration();<\/pre>\n<\/div>\n
    \u8fd0\u884cmapreduce\u7a0b\u5e8f\u524d\u90fd\u8981\u521d\u59cb\u5316Configuration\uff0c\u8be5\u7c7b\u4e3b\u8981\u662f\u8bfb\u53d6mapreduce\u7cfb\u7edf\u914d\u7f6e\u4fe1\u606f\uff0c\u8fd9\u4e9b\u4fe1\u606f\u5305\u62echdfs\u8fd8\u6709mapreduce\uff0c\u4e5f\u5c31\u662f\u5b89\u88c5hadoop\u65f6\u5019\u7684\u914d\u7f6e\u6587\u4ef6\u4f8b\u5982\uff1acore-site.xml\u3001hdfs-site.xml\u548cmapred-site.xml\u7b49\u7b49\u6587\u4ef6\u91cc\u7684\u4fe1\u606f\uff0c\u6709\u4e9b\u7ae5\u978b\u4e0d\u7406\u89e3\u4e3a\u5565\u8981\u8fd9\u4e48\u505a\uff0c\u8fd9\u4e2a\u662f\u6ca1\u6709\u6df1\u5165\u601d\u8003mapreduce\u8ba1\u7b97\u6846\u67b6\u9020\u6210\uff0c\u6211\u4eec\u7a0b\u5e8f\u5458\u5f00\u53d1mapreduce\u65f6\u5019\u53ea\u662f\u5728\u586b\u7a7a\uff0c\u5728map\u51fd\u6570\u548creduce\u51fd\u6570\u91cc\u7f16\u5199\u5b9e\u9645\u8fdb\u884c\u7684\u4e1a\u52a1\u903b\u8f91\uff0c\u5176\u5b83\u7684\u5de5\u4f5c\u90fd\u662f\u4ea4\u7ed9mapreduce\u6846\u67b6\u81ea\u5df1\u64cd\u4f5c\u7684\uff0c\u4f46\u662f\u81f3\u5c11\u6211\u4eec\u8981\u544a\u8bc9\u5b83\u600e\u4e48\u64cd\u4f5c\u554a\uff0c\u6bd4\u5982hdfs\u5728\u54ea\u91cc\u554a\uff0cmapreduce\u7684jobstracker\u5728\u54ea\u91cc\u554a\uff0c\u800c\u8fd9\u4e9b\u4fe1\u606f\u5c31\u5728conf\u5305\u4e0b\u7684\u914d\u7f6e\u6587\u4ef6\u91cc\u3002<\/p>\n
    \u63a5\u4e0b\u6765\u7684\u4ee3\u7801\u662f\uff1a<\/p>\n
    \n
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();\r\n    if (otherArgs.length != 2) {\r\n      System.err.println(\"Usage: wordcount <in> <out>\");\r\n      System.exit(2);\r\n    }<\/pre>\n<\/div>\n
    If\u7684\u8bed\u53e5\u597d\u7406\u89e3\uff0c\u5c31\u662f\u8fd0\u884cWordCount\u7a0b\u5e8f\u65f6\u5019\u4e00\u5b9a\u662f\u4e24\u4e2a\u53c2\u6570\uff0c\u5982\u679c\u4e0d\u662f\u5c31\u4f1a\u62a5\u9519\u9000\u51fa\u3002\u81f3\u4e8e\u7b2c\u4e00\u53e5\u91cc\u7684GenericOptionsParser\u7c7b\uff0c\u5b83\u662f\u7528\u6765\u89e3\u91ca\u5e38\u7528hadoop\u547d\u4ee4\uff0c\u5e76\u6839\u636e\u9700\u8981\u4e3aConfiguration\u5bf9\u8c61\u8bbe\u7f6e\u76f8\u5e94\u7684\u503c\uff0c\u5176\u5b9e\u5e73\u65f6\u5f00\u53d1\u91cc\u6211\u4eec\u4e0d\u592a\u5e38\u7528\u5b83\uff0c\u800c\u662f\u8ba9\u7c7b\u5b9e\u73b0Tool\u63a5\u53e3\uff0c\u7136\u540e\u518dmain\u51fd\u6570\u91cc\u4f7f\u7528ToolRunner\u8fd0\u884c\u7a0b\u5e8f\uff0c\u800cToolRunner\u5185\u90e8\u4f1a\u8c03\u7528GenericOptionsParser\u3002<\/p>\n
    \u63a5\u4e0b\u6765\u7684\u4ee3\u7801\u662f\uff1a<\/p>\n
    \n
        Job job = new Job(conf, \"word count\");\r\n    job.setJarByClass(WordCount.class);\r\n    job.setMapperClass(TokenizerMapper.class);\r\n    job.setCombinerClass(IntSumReducer.class);\r\n    job.setReducerClass(IntSumReducer.class);<\/pre>\n<\/div>\n
    \u7b2c\u4e00\u884c\u5c31\u662f\u5728\u6784\u5efa\u4e00\u4e2ajob\uff0c\u5728mapreduce\u6846\u67b6\u91cc\u4e00\u4e2amapreduce\u4efb\u52a1\u4e5f\u53ebmapreduce\u4f5c\u4e1a\u4e5f\u53eb\u505a\u4e00\u4e2amapreduce\u7684job\uff0c\u800c\u5177\u4f53\u7684map\u548creduce\u8fd0\u7b97\u5c31\u662ftask\u4e86\uff0c\u8fd9\u91cc\u6211\u4eec\u6784\u5efa\u4e00\u4e2ajob\uff0c\u6784\u5efa\u65f6\u5019\u6709\u4e24\u4e2a\u53c2\u6570\uff0c\u4e00\u4e2a\u662fconf\u8fd9\u4e2a\u5c31\u4e0d\u7d2f\u8ff0\u4e86\uff0c\u4e00\u4e2a\u662f\u8fd9\u4e2ajob\u7684\u540d\u79f0\u3002<\/p>\n
    \u7b2c\u4e8c\u884c\u5c31\u662f\u88c5\u8f7d\u7a0b\u5e8f\u5458\u7f16\u5199\u597d\u7684\u8ba1\u7b97\u7a0b\u5e8f\uff0c\u4f8b\u5982\u6211\u4eec\u7684\u7a0b\u5e8f\u7c7b\u540d\u5c31\u662fWordCount\u4e86\u3002\u8fd9\u91cc\u6211\u8981\u505a\u4e0b\u7ea0\u6b63\uff0c\u867d\u7136\u6211\u4eec\u7f16\u5199mapreduce\u7a0b\u5e8f\u53ea\u9700\u8981\u5b9e\u73b0map\u51fd\u6570\u548creduce\u51fd\u6570\uff0c\u4f46\u662f\u5b9e\u9645\u5f00\u53d1\u6211\u4eec\u8981\u5b9e\u73b0\u4e09\u4e2a\u7c7b\uff0c\u7b2c\u4e09\u4e2a\u7c7b\u662f\u4e3a\u4e86\u914d\u7f6emapreduce\u5982\u4f55\u8fd0\u884cmap\u548creduce\u51fd\u6570\uff0c\u51c6\u786e\u7684\u8bf4\u5c31\u662f\u6784\u5efa\u4e00\u4e2amapreduce\u80fd\u6267\u884c\u7684job\u4e86\uff0c\u4f8b\u5982WordCount\u7c7b\u3002<\/p>\n
    \u7b2c\u4e09\u884c\u548c\u7b2c\u4e94\u884c\u5c31\u662f\u88c5\u8f7dmap\u51fd\u6570\u548creduce\u51fd\u6570\u5b9e\u73b0\u7c7b\u4e86\uff0c\u8fd9\u91cc\u591a\u4e86\u4e2a\u7b2c\u56db\u884c\uff0c\u8fd9\u4e2a\u662f\u88c5\u8f7dCombiner\u7c7b\uff0c\u8fd9\u4e2a\u6211\u540e\u9762\u8bb2mapreduce\u8fd0\u884c\u673a\u5236\u65f6\u5019\u4f1a\u8bb2\u8ff0\uff0c\u5176\u5b9e\u672c\u4f8b\u53bb\u6389\u7b2c\u56db\u884c\u4e5f\u6ca1\u6709\u5173\u7cfb\uff0c\u4f46\u662f\u4f7f\u7528\u4e86\u7b2c\u56db\u884c\u7406\u8bba\u4e0a\u8fd0\u884c\u6548\u7387\u4f1a\u66f4\u597d\u3002<\/p>\n
    \u63a5\u4e0b\u6765\u7684\u4ee3\u7801\uff1a<\/p>\n
    \n
        job.setOutputKeyClass(Text.class);\r\n    job.setOutputValueClass(IntWritable.class);<\/pre>\n<\/div>\n
    \u8fd9\u4e2a\u662f\u5b9a\u4e49\u8f93\u51fa\u7684key\/value\u7684\u7c7b\u578b\uff0c\u4e5f\u5c31\u662f\u6700\u7ec8\u5b58\u50a8\u5728hdfs\u4e0a\u7ed3\u679c\u6587\u4ef6\u7684key\/value\u7684\u7c7b\u578b\u3002<\/p>\n
    \u6700\u540e\u7684\u4ee3\u7801\u662f\uff1a<\/p>\n
    \n
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));\r\n    FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));\r\n    System.exit(job.waitForCompletion(true) ? 0 : 1);<\/pre>\n<\/div>\n
    \u7b2c\u4e00\u884c\u5c31\u662f\u6784\u5efa\u8f93\u5165\u7684\u6570\u636e\u6587\u4ef6\uff0c\u7b2c\u4e8c\u884c\u662f\u6784\u5efa\u8f93\u51fa\u7684\u6570\u636e\u6587\u4ef6\uff0c\u6700\u540e\u4e00\u884c\u5982\u679cjob\u8fd0\u884c\u6210\u529f\u4e86\uff0c\u6211\u4eec\u7684\u7a0b\u5e8f\u5c31\u4f1a\u6b63\u5e38\u9000\u51fa\u3002FileInputFormat\u548cFileOutputFormat\u662f\u5f88\u6709\u5b66\u95ee\u7684\uff0c\u6211\u4f1a\u5728\u4e0b\u9762\u7684mapreduce\u8fd0\u884c\u673a\u5236\u91cc\u8bb2\u89e3\u5230\u5b83\u4eec\u3002<\/p>\n
    \u597d\u4e86\uff0cmapreduce\u91cc\u7684hello word\u7a0b\u5e8f\u8bb2\u89e3\u5b8c\u6bd5\uff0c\u6211\u8fd9\u4e2a\u8bb2\u89e3\u662f\u4ece\u65b0\u529eapi\u8fdb\u884c\uff0c\u8fd9\u5957\u8bb2\u89e3\u5728\u7f51\u7edc\u4e0a\u8fd8\u662f\u6bd4\u8f83\u5c11\u7684\uff0c\u5e94\u8be5\u5f88\u5177\u6709\u4ee3\u8868\u6027\u7684\u3002<\/p>\n
    \u3000\u3000Mapreduce<\/em><\/strong>\u8fd0\u884c\u673a\u5236<\/em><\/strong><\/p>\n
    \u4e0b\u9762\u6211\u8981\u8bb2\u8bb2mapreduce\u7684\u8fd0\u884c\u673a\u5236\u4e86\uff0c\u524d\u4e0d\u4e45\u6211\u4e3a\u516c\u53f8\u51fa\u4e86\u4e00\u5957hadoop\u9762\u8bd5\u9898\uff0c\u91cc\u9762\u5c31\u95ee\u9053\u4e86mapreduce\u8fd0\u884c\u673a\u5236\uff0c\u51fa\u9898\u65f6\u5019\u6211\u53d1\u73b0\u8fd9\u4e2a\u95ee\u9898\u6211\u81ea\u5df1\u4f3c\u4e4e\u4e5f\u5c06\u4e0d\u592a\u6e05\u695a\uff0c\u56e0\u6b64\u6700\u8fd1\u51e0\u5929\u6076\u8865\u4e86\u4e0b\uff0c\u5e0c\u671b\u5728\u672c\u6587\u91cc\u80fd\u8bf4\u6e05\u695a\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n
    \u4e0b\u9762\u6211\u8d34\u51fa\u51e0\u5f20\u56fe\uff0c\u8fd9\u4e9b\u56fe\u90fd\u662f\u6211\u5728\u767e\u5ea6\u56fe\u7247\u91cc\u627e\u5230\u7684\u6bd4\u8f83\u597d\u7684\u56fe\u7247\uff1a<\/p>\n
    \u3000\u3000\u56fe\u7247\u4e00\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u3000\u3000\u56fe\u7247\u4e8c\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u3000\u3000\u56fe\u7247\u4e09\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u3000\u3000\u56fe\u7247\u56db\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u3000\u3000\u56fe\u7247\u4e94\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u3000\u3000\u56fe\u7247\u516d\uff1a<\/em><\/p>\n
    \"\"<\/em><\/p>\n
    \u6211\u73b0\u5728\u5b66\u4e60\u6280\u672f\u5f88\u559c\u6b22\u770b\u56fe\uff0c\u6bcf\u6b21\u6709\u4e86\u65b0\u7406\u89e3\u5c31\u4f1a\u53bb\u770b\u770b\u56fe\uff0c\u6bcf\u6b21\u90fd\u4f1a\u6709\u65b0\u7684\u53d1\u73b0\u3002<\/p>\n
    \u8c08mapreduce\u8fd0\u884c\u673a\u5236\uff0c\u53ef\u4ee5\u4ece\u5f88\u591a\u4e0d\u540c\u7684\u89d2\u5ea6\u6765\u63cf\u8ff0\uff0c\u6bd4\u5982\u8bf4\u4ecemapreduce\u8fd0\u884c\u6d41\u7a0b\u6765\u8bb2\u89e3\uff0c\u4e5f\u53ef\u4ee5\u4ece\u8ba1\u7b97\u6a21\u578b\u7684\u903b\u8f91\u6d41\u7a0b\u6765\u8fdb\u884c\u8bb2\u89e3\uff0c\u4e5f\u8bb8\u6709\u4e9b\u6df1\u5165\u7406\u89e3\u4e86mapreduce\u8fd0\u884c\u673a\u5236\u8fd8\u4f1a\u4ece\u66f4\u597d\u7684\u89d2\u5ea6\u6765\u63cf\u8ff0\uff0c\u4f46\u662f\u5c06mapreduce\u8fd0\u884c\u673a\u5236\u6709\u4e9b\u4e1c\u897f\u662f\u907f\u514d\u4e0d\u4e86\u7684\uff0c\u5c31\u662f\u4e00\u4e2a\u4e2a\u53c2\u5165\u7684\u5b9e\u4f8b\u5bf9\u8c61\uff0c\u4e00\u4e2a\u5c31\u662f\u8ba1\u7b97\u6a21\u578b\u7684\u903b\u8f91\u5b9a\u4e49\u9636\u6bb5\uff0c\u6211\u8fd9\u91cc\u8bb2\u89e3\u4e0d\u4ece\u4ec0\u4e48\u6d41\u7a0b\u51fa\u53d1\uff0c\u5c31\u4ece\u8fd9\u4e9b\u4e00\u4e2a\u4e2a\u7275\u6d89\u7684\u5bf9\u8c61\uff0c\u4e0d\u7ba1\u662f\u7269\u7406\u5b9e\u4f53\u8fd8\u662f\u903b\u8f91\u5b9e\u4f53\u3002<\/p>\n
    \u9996\u5148\u8bb2\u8bb2\u7269\u7406\u5b9e\u4f53\uff0c\u53c2\u5165mapreduce\u4f5c\u4e1a\u6267\u884c\u6d89\u53ca4\u4e2a\u72ec\u7acb\u7684\u5b9e\u4f53\uff1a<\/p>\n
      \n
    1. \u5ba2\u6237\u7aef\uff08client\uff09\uff1a\u7f16\u5199mapreduce\u7a0b\u5e8f\uff0c\u914d\u7f6e\u4f5c\u4e1a\uff0c\u63d0\u4ea4\u4f5c\u4e1a\uff0c\u8fd9\u5c31\u662f\u7a0b\u5e8f\u5458\u5b8c\u6210\u7684\u5de5\u4f5c\uff1b<\/li>\n
    2. JobTracker\uff1a\u521d\u59cb\u5316\u4f5c\u4e1a\uff0c\u5206\u914d\u4f5c\u4e1a\uff0c\u4e0eTaskTracker\u901a\u4fe1\uff0c\u534f\u8c03\u6574\u4e2a\u4f5c\u4e1a\u7684\u6267\u884c\uff1b<\/li>\n
    3. TaskTracker\uff1a\u4fdd\u6301\u4e0eJobTracker\u7684\u901a\u4fe1\uff0c\u5728\u5206\u914d\u7684\u6570\u636e\u7247\u6bb5\u4e0a\u6267\u884cMap\u6216Reduce\u4efb\u52a1\uff0cTaskTracker\u548cJobTracker\u7684\u4e0d\u540c\u6709\u4e2a\u5f88\u91cd\u8981\u7684\u65b9\u9762\uff0c\u5c31\u662f\u5728\u6267\u884c\u4efb\u52a1\u65f6\u5019TaskTracker\u53ef\u4ee5\u6709n\u591a\u4e2a\uff0cJobTracker\u5219\u53ea\u4f1a\u6709\u4e00\u4e2a\uff08JobTracker\u53ea\u80fd\u6709\u4e00\u4e2a\u5c31\u548chdfs\u91ccnamenode\u4e00\u6837\u5b58\u5728\u5355\u70b9\u6545\u969c\uff0c\u6211\u4f1a\u5728\u540e\u9762\u7684mapreduce\u7684\u76f8\u5173\u95ee\u9898\u91cc\u8bb2\u5230\u8fd9\u4e2a\u95ee\u9898\u7684\uff09<\/li>\n
    4. Hdfs\uff1a\u4fdd\u5b58\u4f5c\u4e1a\u7684\u6570\u636e\u3001\u914d\u7f6e\u4fe1\u606f\u7b49\u7b49\uff0c\u6700\u540e\u7684\u7ed3\u679c\u4e5f\u662f\u4fdd\u5b58\u5728hdfs\u4e0a\u9762<\/li>\n<\/ol>\n
      \u90a3\u4e48mapreduce\u5230\u5e95\u662f\u5982\u4f55\u8fd0\u884c\u7684\u5462\uff1f<\/em><\/p>\n
       <\/p>\n
      \u9996\u5148\u662f\u5ba2\u6237\u7aef\u8981\u7f16\u5199\u597dmapreduce\u7a0b\u5e8f\uff0c\u914d\u7f6e\u597dmapreduce\u7684\u4f5c\u4e1a\u4e5f\u5c31\u662fjob\uff0c\u63a5\u4e0b\u6765\u5c31\u662f\u63d0\u4ea4job\u4e86\uff0c\u63d0\u4ea4job\u662f\u63d0\u4ea4\u5230JobTracker\u4e0a\u7684\uff0c\u8fd9\u4e2a\u65f6\u5019JobTracker\u5c31\u4f1a\u6784\u5efa\u8fd9\u4e2ajob\uff0c\u5177\u4f53\u5c31\u662f\u5206\u914d\u4e00\u4e2a\u65b0\u7684job\u4efb\u52a1\u7684ID\u503c\uff0c\u63a5\u4e0b\u6765\u5b83\u4f1a\u505a\u68c0\u67e5\u64cd\u4f5c\uff0c\u8fd9\u4e2a\u68c0\u67e5\u5c31\u662f\u786e\u5b9a\u8f93\u51fa\u76ee\u5f55\u662f\u5426\u5b58\u5728\uff0c\u5982\u679c\u5b58\u5728\u90a3\u4e48job\u5c31\u4e0d\u80fd\u6b63\u5e38\u8fd0\u884c\u4e0b\u53bb\uff0cJobTracker\u4f1a\u629b\u51fa\u9519\u8bef\u7ed9\u5ba2\u6237\u7aef\uff0c\u63a5\u4e0b\u6765\u8fd8\u8981\u68c0\u67e5\u8f93\u5165\u76ee\u5f55\u662f\u5426\u5b58\u5728\uff0c\u5982\u679c\u4e0d\u5b58\u5728\u540c\u6837\u629b\u51fa\u9519\u8bef\uff0c\u5982\u679c\u5b58\u5728JobTracker\u4f1a\u6839\u636e\u8f93\u5165\u8ba1\u7b97\u8f93\u5165\u5206\u7247\uff08Input Split\uff09\uff0c\u5982\u679c\u5206\u7247\u8ba1\u7b97\u4e0d\u51fa\u6765\u4e5f\u4f1a\u629b\u51fa\u9519\u8bef\uff0c\u81f3\u4e8e\u8f93\u5165\u5206\u7247\u6211\u540e\u9762\u4f1a\u505a\u8bb2\u89e3\u7684\uff0c\u8fd9\u4e9b\u90fd\u505a\u597d\u4e86JobTracker\u5c31\u4f1a\u914d\u7f6eJob\u9700\u8981\u7684\u8d44\u6e90\u4e86\u3002\u5206\u914d\u597d\u8d44\u6e90\u540e\uff0cJobTracker\u5c31\u4f1a\u521d\u59cb\u5316\u4f5c\u4e1a\uff0c\u521d\u59cb\u5316\u4e3b\u8981\u505a\u7684\u662f\u5c06Job\u653e\u5165\u4e00\u4e2a\u5185\u90e8\u7684\u961f\u5217\uff0c\u8ba9\u914d\u7f6e\u597d\u7684\u4f5c\u4e1a\u8c03\u5ea6\u5668\u80fd\u8c03\u5ea6\u5230\u8fd9\u4e2a\u4f5c\u4e1a\uff0c\u4f5c\u4e1a\u8c03\u5ea6\u5668\u4f1a\u521d\u59cb\u5316\u8fd9\u4e2ajob\uff0c\u521d\u59cb\u5316\u5c31\u662f\u521b\u5efa\u4e00\u4e2a\u6b63\u5728\u8fd0\u884c\u7684job\u5bf9\u8c61\uff08\u5c01\u88c5\u4efb\u52a1\u548c\u8bb0\u5f55\u4fe1\u606f\uff09\uff0c\u4ee5\u4fbfJobTracker\u8ddf\u8e2ajob\u7684\u72b6\u6001\u548c\u8fdb\u7a0b\u3002\u521d\u59cb\u5316\u5b8c\u6bd5\u540e\uff0c\u4f5c\u4e1a\u8c03\u5ea6\u5668\u4f1a\u83b7\u53d6\u8f93\u5165\u5206\u7247\u4fe1\u606f\uff08input split\uff09\uff0c\u6bcf\u4e2a\u5206\u7247\u521b\u5efa\u4e00\u4e2amap\u4efb\u52a1\u3002\u63a5\u4e0b\u6765\u5c31\u662f\u4efb\u52a1\u5206\u914d\u4e86\uff0c\u8fd9\u4e2a\u65f6\u5019tasktracker\u4f1a\u8fd0\u884c\u4e00\u4e2a\u7b80\u5355\u7684\u5faa\u73af\u673a\u5236\u5b9a\u671f\u53d1\u9001\u5fc3\u8df3\u7ed9jobtracker\uff0c\u5fc3\u8df3\u95f4\u9694\u662f5\u79d2\uff0c\u7a0b\u5e8f\u5458\u53ef\u4ee5\u914d\u7f6e\u8fd9\u4e2a\u65f6\u95f4\uff0c\u5fc3\u8df3\u5c31\u662fjobtracker\u548ctasktracker\u6c9f\u901a\u7684\u6865\u6881\uff0c\u901a\u8fc7\u5fc3\u8df3\uff0cjobtracker\u53ef\u4ee5\u76d1\u63a7tasktracker\u662f\u5426\u5b58\u6d3b\uff0c\u4e5f\u53ef\u4ee5\u83b7\u53d6tasktracker\u5904\u7406\u7684\u72b6\u6001\u548c\u95ee\u9898\uff0c\u540c\u65f6tasktracker\u4e5f\u53ef\u4ee5\u901a\u8fc7\u5fc3\u8df3\u91cc\u7684\u8fd4\u56de\u503c\u83b7\u53d6jobtracker\u7ed9\u5b83\u7684\u64cd\u4f5c\u6307\u4ee4\u3002\u4efb\u52a1\u5206\u914d\u597d\u540e\u5c31\u662f\u6267\u884c\u4efb\u52a1\u4e86\u3002\u5728\u4efb\u52a1\u6267\u884c\u65f6\u5019jobtracker\u53ef\u4ee5\u901a\u8fc7\u5fc3\u8df3\u673a\u5236\u76d1\u63a7tasktracker\u7684\u72b6\u6001\u548c\u8fdb\u5ea6\uff0c\u540c\u65f6\u4e5f\u80fd\u8ba1\u7b97\u51fa\u6574\u4e2ajob\u7684\u72b6\u6001\u548c\u8fdb\u5ea6\uff0c\u800ctasktracker\u4e5f\u53ef\u4ee5\u672c\u5730\u76d1\u63a7\u81ea\u5df1\u7684\u72b6\u6001\u548c\u8fdb\u5ea6\u3002\u5f53jobtracker\u83b7\u5f97\u4e86\u6700\u540e\u4e00\u4e2a\u5b8c\u6210\u6307\u5b9a\u4efb\u52a1\u7684tasktracker\u64cd\u4f5c\u6210\u529f\u7684\u901a\u77e5\u65f6\u5019\uff0cjobtracker\u4f1a\u628a\u6574\u4e2ajob\u72b6\u6001\u7f6e\u4e3a\u6210\u529f\uff0c\u7136\u540e\u5f53\u5ba2\u6237\u7aef\u67e5\u8be2job\u8fd0\u884c\u72b6\u6001\u65f6\u5019\uff08\u6ce8\u610f\uff1a\u8fd9\u4e2a\u662f\u5f02\u6b65\u64cd\u4f5c\uff09\uff0c\u5ba2\u6237\u7aef\u4f1a\u67e5\u5230job\u5b8c\u6210\u7684\u901a\u77e5\u7684\u3002\u5982\u679cjob\u4e2d\u9014\u5931\u8d25\uff0cmapreduce\u4e5f\u4f1a\u6709\u76f8\u5e94\u673a\u5236\u5904\u7406\uff0c\u4e00\u822c\u800c\u8a00\u5982\u679c\u4e0d\u662f\u7a0b\u5e8f\u5458\u7a0b\u5e8f\u672c\u8eab\u6709bug\uff0cmapreduce\u9519\u8bef\u5904\u7406\u673a\u5236\u90fd\u80fd\u4fdd\u8bc1\u63d0\u4ea4\u7684job\u80fd\u6b63\u5e38\u5b8c\u6210\u3002<\/p>\n
       <\/p>\n
      \u4e0b\u9762\u6211\u4ece\u903b\u8f91\u5b9e\u4f53\u7684\u89d2\u5ea6\u8bb2\u89e3mapreduce\u8fd0\u884c\u673a\u5236\uff0c\u8fd9\u4e9b\u6309\u7167\u65f6\u95f4\u987a\u5e8f\u5305\u62ec\uff1a\u8f93\u5165\u5206\u7247\uff08<\/em><\/strong>input split<\/em><\/strong>\uff09\u3001map<\/em><\/strong>\u9636\u6bb5\u3001combiner<\/em><\/strong>\u9636\u6bb5\u3001shuffle<\/em><\/strong>\u9636\u6bb5\u548creduce<\/em><\/strong>\u9636\u6bb5<\/em><\/strong>\u3002<\/p>\n
        \n
      1. \u8f93\u5165\u5206\u7247\uff08input split<\/strong>\uff09\uff1a<\/strong>\u5728\u8fdb\u884cmap\u8ba1\u7b97\u4e4b\u524d\uff0cmapreduce\u4f1a\u6839\u636e\u8f93\u5165\u6587\u4ef6\u8ba1\u7b97\u8f93\u5165\u5206\u7247\uff08input split\uff09\uff0c\u6bcf\u4e2a\u8f93\u5165\u5206\u7247\uff08input split\uff09\u9488\u5bf9\u4e00\u4e2amap\u4efb\u52a1\uff0c\u8f93\u5165\u5206\u7247\uff08input split\uff09\u5b58\u50a8\u7684\u5e76\u975e\u6570\u636e\u672c\u8eab\uff0c\u800c\u662f\u4e00\u4e2a\u5206\u7247\u957f\u5ea6\u548c\u4e00\u4e2a\u8bb0\u5f55\u6570\u636e\u7684\u4f4d\u7f6e\u7684\u6570\u7ec4\uff0c\u8f93\u5165\u5206\u7247\uff08input split\uff09\u5f80\u5f80\u548chdfs\u7684block\uff08\u5757\uff09\u5173\u7cfb\u5f88\u5bc6\u5207\uff0c\u5047\u5982\u6211\u4eec\u8bbe\u5b9ahdfs\u7684\u5757\u7684\u5927\u5c0f\u662f64mb\uff0c\u5982\u679c\u6211\u4eec\u8f93\u5165\u6709\u4e09\u4e2a\u6587\u4ef6\uff0c\u5927\u5c0f\u5206\u522b\u662f3mb\u300165mb\u548c127mb\uff0c\u90a3\u4e48mapreduce\u4f1a\u628a3mb\u6587\u4ef6\u5206\u4e3a\u4e00\u4e2a\u8f93\u5165\u5206\u7247\uff08input split\uff09\uff0c65mb\u5219\u662f\u4e24\u4e2a\u8f93\u5165\u5206\u7247\uff08input split\uff09\u800c127mb\u4e5f\u662f\u4e24\u4e2a\u8f93\u5165\u5206\u7247\uff08input split\uff09\uff0c\u6362\u53e5\u8bdd\u8bf4\u6211\u4eec\u5982\u679c\u5728map\u8ba1\u7b97\u524d\u505a\u8f93\u5165\u5206\u7247\u8c03\u6574\uff0c\u4f8b\u5982\u5408\u5e76\u5c0f\u6587\u4ef6\uff0c\u90a3\u4e48\u5c31\u4f1a\u67095\u4e2amap\u4efb\u52a1\u5c06\u6267\u884c\uff0c\u800c\u4e14\u6bcf\u4e2amap\u6267\u884c\u7684\u6570\u636e\u5927\u5c0f\u4e0d\u5747\uff0c\u8fd9\u4e2a\u4e5f\u662fmapreduce\u4f18\u5316\u8ba1\u7b97\u7684\u4e00\u4e2a\u5173\u952e\u70b9\u3002<\/li>\n
      2. map<\/strong>\u9636\u6bb5\uff1a<\/strong>\u5c31\u662f\u7a0b\u5e8f\u5458\u7f16\u5199\u597d\u7684map\u51fd\u6570\u4e86\uff0c\u56e0\u6b64map\u51fd\u6570\u6548\u7387\u76f8\u5bf9\u597d\u63a7\u5236\uff0c\u800c\u4e14\u4e00\u822cmap\u64cd\u4f5c\u90fd\u662f\u672c\u5730\u5316\u64cd\u4f5c\u4e5f\u5c31\u662f\u5728\u6570\u636e\u5b58\u50a8\u8282\u70b9\u4e0a\u8fdb\u884c\uff1b<\/li>\n
      3. combiner<\/strong>\u9636\u6bb5\uff1ac<\/strong>ombiner\u9636\u6bb5\u662f\u7a0b\u5e8f\u5458\u53ef\u4ee5\u9009\u62e9\u7684\uff0ccombiner\u5176\u5b9e\u4e5f\u662f\u4e00\u79cdreduce\u64cd\u4f5c\uff0c\u56e0\u6b64\u6211\u4eec\u770b\u89c1WordCount\u7c7b\u91cc\u662f\u7528reduce\u8fdb\u884c\u52a0\u8f7d\u7684\u3002Combiner\u662f\u4e00\u4e2a\u672c\u5730\u5316\u7684reduce\u64cd\u4f5c\uff0c\u5b83\u662fmap\u8fd0\u7b97\u7684\u540e\u7eed\u64cd\u4f5c\uff0c\u4e3b\u8981\u662f\u5728map\u8ba1\u7b97\u51fa\u4e2d\u95f4\u6587\u4ef6\u524d\u505a\u4e00\u4e2a\u7b80\u5355\u7684\u5408\u5e76\u91cd\u590dkey\u503c\u7684\u64cd\u4f5c\uff0c\u4f8b\u5982\u6211\u4eec\u5bf9\u6587\u4ef6\u91cc\u7684\u5355\u8bcd\u9891\u7387\u505a\u7edf\u8ba1\uff0cmap\u8ba1\u7b97\u65f6\u5019\u5982\u679c\u78b0\u5230\u4e00\u4e2ahadoop\u7684\u5355\u8bcd\u5c31\u4f1a\u8bb0\u5f55\u4e3a1\uff0c\u4f46\u662f\u8fd9\u7bc7\u6587\u7ae0\u91cchadoop\u53ef\u80fd\u4f1a\u51fa\u73b0n\u591a\u6b21\uff0c\u90a3\u4e48map\u8f93\u51fa\u6587\u4ef6\u5197\u4f59\u5c31\u4f1a\u5f88\u591a\uff0c\u56e0\u6b64\u5728reduce\u8ba1\u7b97\u524d\u5bf9\u76f8\u540c\u7684key\u505a\u4e00\u4e2a\u5408\u5e76\u64cd\u4f5c\uff0c\u90a3\u4e48\u6587\u4ef6\u4f1a\u53d8\u5c0f\uff0c\u8fd9\u6837\u5c31\u63d0\u9ad8\u4e86\u5bbd\u5e26\u7684\u4f20\u8f93\u6548\u7387\uff0c\u6bd5\u7adfhadoop\u8ba1\u7b97\u529b\u5bbd\u5e26\u8d44\u6e90\u5f80\u5f80\u662f\u8ba1\u7b97\u7684\u74f6\u9888\u4e5f\u662f\u6700\u4e3a\u5b9d\u8d35\u7684\u8d44\u6e90\uff0c\u4f46\u662fcombiner\u64cd\u4f5c\u662f\u6709\u98ce\u9669\u7684\uff0c\u4f7f\u7528\u5b83\u7684\u539f\u5219\u662fcombiner\u7684\u8f93\u5165\u4e0d\u4f1a\u5f71\u54cd\u5230reduce\u8ba1\u7b97\u7684\u6700\u7ec8\u8f93\u5165\uff0c\u4f8b\u5982\uff1a\u5982\u679c\u8ba1\u7b97\u53ea\u662f\u6c42\u603b\u6570\uff0c\u6700\u5927\u503c\uff0c\u6700\u5c0f\u503c\u53ef\u4ee5\u4f7f\u7528combiner\uff0c\u4f46\u662f\u505a\u5e73\u5747\u503c\u8ba1\u7b97\u4f7f\u7528combiner\u7684\u8bdd\uff0c\u6700\u7ec8\u7684reduce\u8ba1\u7b97\u7ed3\u679c\u5c31\u4f1a\u51fa\u9519\u3002<\/li>\n
      4. shuffle<\/strong>\u9636\u6bb5\uff1a<\/strong>\u5c06map\u7684\u8f93\u51fa\u4f5c\u4e3areduce\u7684\u8f93\u5165\u7684\u8fc7\u7a0b\u5c31\u662fshuffle\u4e86\uff0c\u8fd9\u4e2a\u662fmapreduce\u4f18\u5316\u7684\u91cd\u70b9\u5730\u65b9\u3002\u8fd9\u91cc\u6211\u4e0d\u8bb2\u600e\u4e48\u4f18\u5316shuffle\u9636\u6bb5\uff0c\u8bb2\u8bb2shuffle\u9636\u6bb5\u7684\u539f\u7406\uff0c\u56e0\u4e3a\u5927\u90e8\u5206\u7684\u4e66\u7c4d\u91cc\u90fd\u6ca1\u8bb2\u6e05\u695ashuffle\u9636\u6bb5\u3002Shuffle\u4e00\u5f00\u59cb\u5c31\u662fmap\u9636\u6bb5\u505a\u8f93\u51fa\u64cd\u4f5c\uff0c\u4e00\u822cmapreduce\u8ba1\u7b97\u7684\u90fd\u662f\u6d77\u91cf\u6570\u636e\uff0cmap\u8f93\u51fa\u65f6\u5019\u4e0d\u53ef\u80fd\u628a\u6240\u6709\u6587\u4ef6\u90fd\u653e\u5230\u5185\u5b58\u64cd\u4f5c\uff0c\u56e0\u6b64map\u5199\u5165\u78c1\u76d8\u7684\u8fc7\u7a0b\u5341\u5206\u7684\u590d\u6742\uff0c\u66f4\u4f55\u51b5map\u8f93\u51fa\u65f6\u5019\u8981\u5bf9\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\uff0c\u5185\u5b58\u5f00\u9500\u662f\u5f88\u5927\u7684\uff0cmap\u5728\u505a\u8f93\u51fa\u65f6\u5019\u4f1a\u5728\u5185\u5b58\u91cc\u5f00\u542f\u4e00\u4e2a\u73af\u5f62\u5185\u5b58\u7f13\u51b2\u533a\uff0c\u8fd9\u4e2a\u7f13\u51b2\u533a\u4e13\u95e8\u7528\u6765\u8f93\u51fa\u7684\uff0c\u9ed8\u8ba4\u5927\u5c0f\u662f100mb\uff0c\u5e76\u4e14\u5728\u914d\u7f6e\u6587\u4ef6\u91cc\u4e3a\u8fd9\u4e2a\u7f13\u51b2\u533a\u8bbe\u5b9a\u4e86\u4e00\u4e2a\u9600\u503c\uff0c\u9ed8\u8ba4\u662f0.80\uff08\u8fd9\u4e2a\u5927\u5c0f\u548c\u9600\u503c\u90fd\u662f\u53ef\u4ee5\u5728\u914d\u7f6e\u6587\u4ef6\u91cc\u8fdb\u884c\u914d\u7f6e\u7684\uff09\uff0c\u540c\u65f6map\u8fd8\u4f1a\u4e3a\u8f93\u51fa\u64cd\u4f5c\u542f\u52a8\u4e00\u4e2a\u5b88\u62a4\u7ebf\u7a0b\uff0c\u5982\u679c\u7f13\u51b2\u533a\u7684\u5185\u5b58\u8fbe\u5230\u4e86\u9600\u503c\u768480%\u65f6\u5019\uff0c\u8fd9\u4e2a\u5b88\u62a4\u7ebf\u7a0b\u5c31\u4f1a\u628a\u5185\u5bb9\u5199\u5230\u78c1\u76d8\u4e0a\uff0c\u8fd9\u4e2a\u8fc7\u7a0b\u53ebspill\uff0c\u53e6\u5916\u768420%\u5185\u5b58\u53ef\u4ee5\u7ee7\u7eed\u5199\u5165\u8981\u5199\u8fdb\u78c1\u76d8\u7684\u6570\u636e\uff0c\u5199\u5165\u78c1\u76d8\u548c\u5199\u5165\u5185\u5b58\u64cd\u4f5c\u662f\u4e92\u4e0d\u5e72\u6270\u7684\uff0c\u5982\u679c\u7f13\u5b58\u533a\u88ab\u6491\u6ee1\u4e86\uff0c\u90a3\u4e48map\u5c31\u4f1a\u963b\u585e\u5199\u5165\u5185\u5b58\u7684\u64cd\u4f5c\uff0c\u8ba9\u5199\u5165\u78c1\u76d8\u64cd\u4f5c\u5b8c\u6210\u540e\u518d\u7ee7\u7eed\u6267\u884c\u5199\u5165\u5185\u5b58\u64cd\u4f5c\uff0c\u524d\u9762\u6211\u8bb2\u5230\u5199\u5165\u78c1\u76d8\u524d\u4f1a\u6709\u4e2a\u6392\u5e8f\u64cd\u4f5c\uff0c\u8fd9\u4e2a\u662f\u5728\u5199\u5165\u78c1\u76d8\u64cd\u4f5c\u65f6\u5019\u8fdb\u884c\uff0c\u4e0d\u662f\u5728\u5199\u5165\u5185\u5b58\u65f6\u5019\u8fdb\u884c\u7684\uff0c\u5982\u679c\u6211\u4eec\u5b9a\u4e49\u4e86combiner\u51fd\u6570\uff0c\u90a3\u4e48\u6392\u5e8f\u524d\u8fd8\u4f1a\u6267\u884ccombiner\u64cd\u4f5c\u3002\u6bcf\u6b21spill\u64cd\u4f5c\u4e5f\u5c31\u662f\u5199\u5165\u78c1\u76d8\u64cd\u4f5c\u65f6\u5019\u5c31\u4f1a\u5199\u4e00\u4e2a\u6ea2\u51fa\u6587\u4ef6\uff0c\u4e5f\u5c31\u662f\u8bf4\u5728\u505amap\u8f93\u51fa\u6709\u51e0\u6b21spill\u5c31\u4f1a\u4ea7\u751f\u591a\u5c11\u4e2a\u6ea2\u51fa\u6587\u4ef6\uff0c\u7b49map\u8f93\u51fa\u5168\u90e8\u505a\u5b8c\u540e\uff0cmap\u4f1a\u5408\u5e76\u8fd9\u4e9b\u8f93\u51fa\u6587\u4ef6\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u91cc\u8fd8\u4f1a\u6709\u4e00\u4e2aPartitioner\u64cd\u4f5c\uff0c\u5bf9\u4e8e\u8fd9\u4e2a\u64cd\u4f5c\u5f88\u591a\u4eba\u90fd\u5f88\u8ff7\u7cca\uff0c\u5176\u5b9ePartitioner\u64cd\u4f5c\u548cmap\u9636\u6bb5\u7684\u8f93\u5165\u5206\u7247\uff08Input split\uff09\u5f88\u50cf\uff0c\u4e00\u4e2aPartitioner\u5bf9\u5e94\u4e00\u4e2areduce\u4f5c\u4e1a\uff0c\u5982\u679c\u6211\u4eecmapreduce\u64cd\u4f5c\u53ea\u6709\u4e00\u4e2areduce\u64cd\u4f5c\uff0c\u90a3\u4e48Partitioner\u5c31\u53ea\u6709\u4e00\u4e2a\uff0c\u5982\u679c\u6211\u4eec\u6709\u591a\u4e2areduce\u64cd\u4f5c\uff0c\u90a3\u4e48Partitioner\u5bf9\u5e94\u7684\u5c31\u4f1a\u6709\u591a\u4e2a\uff0cPartitioner\u56e0\u6b64\u5c31\u662freduce\u7684\u8f93\u5165\u5206\u7247\uff0c\u8fd9\u4e2a\u7a0b\u5e8f\u5458\u53ef\u4ee5\u7f16\u7a0b\u63a7\u5236\uff0c\u4e3b\u8981\u662f\u6839\u636e\u5b9e\u9645key\u548cvalue\u7684\u503c\uff0c\u6839\u636e\u5b9e\u9645\u4e1a\u52a1\u7c7b\u578b\u6216\u8005\u4e3a\u4e86\u66f4\u597d\u7684reduce\u8d1f\u8f7d\u5747\u8861\u8981\u6c42\u8fdb\u884c\uff0c\u8fd9\u662f\u63d0\u9ad8reduce\u6548\u7387\u7684\u4e00\u4e2a\u5173\u952e\u6240\u5728\u3002\u5230\u4e86reduce\u9636\u6bb5\u5c31\u662f\u5408\u5e76map\u8f93\u51fa\u6587\u4ef6\u4e86\uff0cPartitioner\u4f1a\u627e\u5230\u5bf9\u5e94\u7684map\u8f93\u51fa\u6587\u4ef6\uff0c\u7136\u540e\u8fdb\u884c\u590d\u5236\u64cd\u4f5c\uff0c\u590d\u5236\u64cd\u4f5c\u65f6reduce\u4f1a\u5f00\u542f\u51e0\u4e2a\u590d\u5236\u7ebf\u7a0b\uff0c\u8fd9\u4e9b\u7ebf\u7a0b\u9ed8\u8ba4\u4e2a\u6570\u662f5\u4e2a\uff0c\u7a0b\u5e8f\u5458\u4e5f\u53ef\u4ee5\u5728\u914d\u7f6e\u6587\u4ef6\u66f4\u6539\u590d\u5236\u7ebf\u7a0b\u7684\u4e2a\u6570\uff0c\u8fd9\u4e2a\u590d\u5236\u8fc7\u7a0b\u548cmap\u5199\u5165\u78c1\u76d8\u8fc7\u7a0b\u7c7b\u4f3c\uff0c\u4e5f\u6709\u9600\u503c\u548c\u5185\u5b58\u5927\u5c0f\uff0c\u9600\u503c\u4e00\u6837\u53ef\u4ee5\u5728\u914d\u7f6e\u6587\u4ef6\u91cc\u914d\u7f6e\uff0c\u800c\u5185\u5b58\u5927\u5c0f\u662f\u76f4\u63a5\u4f7f\u7528reduce\u7684tasktracker\u7684\u5185\u5b58\u5927\u5c0f\uff0c\u590d\u5236\u65f6\u5019reduce\u8fd8\u4f1a\u8fdb\u884c\u6392\u5e8f\u64cd\u4f5c\u548c\u5408\u5e76\u6587\u4ef6\u64cd\u4f5c\uff0c\u8fd9\u4e9b\u64cd\u4f5c\u5b8c\u4e86\u5c31\u4f1a\u8fdb\u884creduce\u8ba1\u7b97\u4e86\u3002<\/li>\n
      5. reduce<\/strong>\u9636\u6bb5<\/strong>\uff1a\u548cmap\u51fd\u6570\u4e00\u6837\u4e5f\u662f\u7a0b\u5e8f\u5458\u7f16\u5199\u7684\uff0c\u6700\u7ec8\u7ed3\u679c\u662f\u5b58\u50a8\u5728hdfs\u4e0a\u7684\u3002<\/li>\n<\/ol>\n
        \u3000\u3000Mapreduce<\/strong>\u7684\u76f8\u5173\u95ee\u9898<\/strong><\/p>\n
        \u8fd9\u91cc\u6211\u8981\u8c08\u8c08\u6211\u5b66\u4e60mapreduce\u601d\u8003\u7684\u4e00\u4e9b\u95ee\u9898\uff0c\u90fd\u662f\u6211\u81ea\u5df1\u60f3\u51fa\u89e3\u91ca\u7684\u95ee\u9898\uff0c\u4f46\u662f\u67d0\u4e9b\u95ee\u9898\u5230\u5e95\u5bf9\u4e0d\u5bf9\uff0c\u5c31\u8981\u5e7f\u5927\u7ae5\u978b\u5e2e\u6211\u786e\u8ba4\u4e86\u3002<\/p>\n
          \n
        1. jobtracker\u7684\u5355\u70b9\u6545\u969c\uff1ajobtracker\u548chdfs\u7684namenode\u4e00\u6837\u4e5f\u5b58\u5728\u5355\u70b9\u6545\u969c\uff0c\u5355\u70b9\u6545\u969c\u4e00\u76f4\u662fhadoop\u88ab\u4eba\u8bdf\u75c5\u7684\u5927\u95ee\u9898\uff0c\u4e3a\u4ec0\u4e48hadoop\u7684\u505a\u7684\u6587\u4ef6\u7cfb\u7edf\u548cmapreduce\u8ba1\u7b97\u6846\u67b6\u90fd\u662f\u9ad8\u5bb9\u9519\u7684\uff0c\u4f46\u662f\u6700\u91cd\u8981\u7684\u7ba1\u7406\u8282\u70b9\u7684\u6545\u969c\u673a\u5236\u5374\u5982\u6b64\u4e0d\u597d\uff0c\u6211\u8ba4\u4e3a\u4e3b\u8981\u662fnamenode\u548cjobtracker\u5728\u5b9e\u9645\u8fd0\u884c\u4e2d\u90fd\u662f\u5728\u5185\u5b58\u64cd\u4f5c\uff0c\u800c\u505a\u5230\u5185\u5b58\u7684\u5bb9\u9519\u5c31\u6bd4\u8f83\u590d\u6742\u4e86\uff0c\u53ea\u6709\u5f53\u5185\u5b58\u6570\u636e\u88ab\u6301\u4e45\u5316\u540e\u5bb9\u9519\u624d\u597d\u505a\uff0cnamenode\u548cjobtracker\u90fd\u53ef\u4ee5\u5907\u4efd\u81ea\u5df1\u6301\u4e45\u5316\u7684\u6587\u4ef6\uff0c\u4f46\u662f\u8fd9\u4e2a\u6301\u4e45\u5316\u90fd\u4f1a\u6709\u5ef6\u8fdf\uff0c\u56e0\u6b64\u771f\u7684\u51fa\u6545\u969c\uff0c\u4efb\u7136\u4e0d\u80fd\u6574\u4f53\u6062\u590d\uff0c\u53e6\u5916hadoop\u6846\u67b6\u91cc\u5305\u542bzookeeper\u6846\u67b6\uff0czookeeper\u53ef\u4ee5\u7ed3\u5408jobtracker\uff0c\u7528\u51e0\u53f0\u673a\u5668\u540c\u65f6\u90e8\u7f72jobtracker\uff0c\u4fdd\u8bc1\u4e00\u53f0\u51fa\u6545\u969c\uff0c\u6709\u4e00\u53f0\u9a6c\u4e0a\u80fd\u8865\u5145\u4e0a\uff0c\u4e0d\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u4e5f\u6ca1\u6cd5\u6062\u590d\u6b63\u5728\u8dd1\u7684mapreduce\u4efb\u52a1\u3002<\/li>\n
        2. \u505amapreduce\u8ba1\u7b97\u65f6\u5019\uff0c\u8f93\u51fa\u4e00\u822c\u662f\u4e00\u4e2a\u6587\u4ef6\u5939\uff0c\u800c\u4e14\u8be5\u6587\u4ef6\u5939\u662f\u4e0d\u80fd\u5b58\u5728\uff0c\u6211\u5728\u51fa\u9762\u8bd5\u9898\u65f6\u5019\u63d0\u5230\u4e86\u8fd9\u4e2a\u95ee\u9898\uff0c\u800c\u4e14\u8fd9\u4e2a\u68c0\u67e5\u505a\u7684\u5f88\u65e9\uff0c\u5f53\u6211\u4eec\u63d0\u4ea4job\u65f6\u5019\u5c31\u4f1a\u8fdb\u884c\uff0cmapreduce\u4e4b\u6240\u4ee5\u8fd9\u4e48\u8bbe\u8ba1\u662f\u4fdd\u8bc1\u6570\u636e\u53ef\u9760\u6027\uff0c\u5982\u679c\u8f93\u51fa\u76ee\u5f55\u5b58\u5728reduce\u5c31\u641e\u4e0d\u6e05\u695a\u4f60\u5230\u5e95\u662f\u8981\u8ffd\u52a0\u8fd8\u662f\u8986\u76d6\uff0c\u4e0d\u7ba1\u662f\u8ffd\u52a0\u548c\u8986\u76d6\u64cd\u4f5c\u90fd\u4f1a\u6709\u53ef\u80fd\u5bfc\u81f4\u6700\u7ec8\u7ed3\u679c\u51fa\u95ee\u9898\uff0cmapreduce\u662f\u505a\u6d77\u91cf\u6570\u636e\u8ba1\u7b97\uff0c\u4e00\u4e2a\u751f\u4ea7\u8ba1\u7b97\u7684\u6210\u672c\u5f88\u9ad8\uff0c\u4f8b\u5982\u4e00\u4e2ajob\u5b8c\u5168\u6267\u884c\u5b8c\u53ef\u80fd\u8981\u51e0\u4e2a\u5c0f\u65f6\uff0c\u56e0\u6b64\u4e00\u5207\u5f71\u54cd\u9519\u8bef\u7684\u60c5\u51b5mapreduce\u662f\u96f6\u5bb9\u5fcd\u7684\u3002<\/li>\n
        3. Mapreduce\u8fd8\u6709\u4e00\u4e2aInputFormat\u548cOutputFormat\uff0c\u6211\u4eec\u5728\u7f16\u5199map\u51fd\u6570\u65f6\u5019\u53d1\u73b0map\u65b9\u6cd5\u7684\u53c2\u6570\u662f\u4e4b\u95f4\u64cd\u4f5c\u884c\u6570\u636e\uff0c\u6ca1\u6709\u7275\u6d89\u5230InputFormat\uff0c\u8fd9\u4e9b\u4e8b\u60c5\u5728\u6211\u4eecnew Path\u65f6\u5019mapreduce\u8ba1\u7b97\u6846\u67b6\u5e2e\u6211\u4eec\u505a\u597d\u4e86\uff0c\u800cOutputFormat\u4e5f\u662freduce\u5e2e\u6211\u4eec\u505a\u597d\u4e86\uff0c\u6211\u4eec\u4f7f\u7528\u4ec0\u4e48\u6837\u7684\u8f93\u5165\u6587\u4ef6\uff0c\u5c31\u8981\u8c03\u7528\u4ec0\u4e48\u6837\u7684InputFormat\uff0cInputFormat\u662f\u548c\u6211\u4eec\u8f93\u5165\u7684\u6587\u4ef6\u7c7b\u578b\u76f8\u5173\u7684\uff0cmapreduce\u91cc\u5e38\u7528\u7684InputFormat\u6709FileInputFormat\u666e\u901a\u6587\u672c\u6587\u4ef6\uff0cSequenceFileInputFormat\u662f\u6307hadoop\u7684\u5e8f\u5217\u5316\u6587\u4ef6\uff0c\u53e6\u5916\u8fd8\u6709KeyValueTextInputFormat\u3002OutputFormat\u5c31\u662f\u6211\u4eec\u60f3\u6700\u7ec8\u5b58\u50a8\u5230hdfs\u7cfb\u7edf\u4e0a\u7684\u6587\u4ef6\u683c\u5f0f\u4e86\uff0c\u8fd9\u4e2a\u6839\u636e\u4f60\u9700\u8981\u5b9a\u4e49\u4e86\uff0chadoop\u6709\u652f\u6301\u5f88\u591a\u6587\u4ef6\u683c\u5f0f\uff0c\u8fd9\u91cc\u4e0d\u4e00\u4e00\u5217\u4e3e\uff0c\u60f3\u77e5\u9053\u767e\u5ea6\u4e0b\u5c31\u770b\u5230\u4e86\u3002<\/li>\n<\/ol>\n
          \u597d\u4e86\uff0c\u6587\u7ae0\u5199\u5b8c\u4e86\uff0c\u5475\u5475\uff0c\u8fd9\u7bc7\u6211\u81ea\u5df1\u611f\u89c9\u5199\u7684\u4e0d\u9519\uff0c\u662f\u76ee\u524dhadoop\u7cfb\u5217\u6587\u7ae0\u91cc\u5199\u7684\u6700\u597d\u7684\uff0c\u6211\u540e\u9762\u4f1a\u518d\u63a5\u518d\u5389\u7684\u3002\u52a0\u6cb9\uff01\uff01\uff01<\/p>\n
           <\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
          \u3000\u3000\u5f00\u59cb\u804amapreduce\uff0cmapre<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[24],"tags":[121],"class_list":["post-1716","post","type-post","status-publish","format-standard","hentry","category-value_docs","tag-05-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1716","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=1716"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1716\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=1716"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=1716"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=1716"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}