MapReduce八股文模板

xiaoxiao2021-02-28  102

package com.bruce.mapreduce; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; public class moduleMapReduce extends Configured implements Tool { // step 1: Map Class /** * Mapper<KEYIN, VALUEIN, KEYOUT, VALUEOUT> * */ //TODO update paragram public static class ModuleMapper extends Mapper<LongWritable, Text, Text, IntWritable> { @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { // TODO Auto-generated method stub } } // step 2: Reduce Class /** * Reducer<KEYIN, VALUEIN, KEYOUT, VALUEOUT> * */ //TODO public static class ModuleReducer extends Reducer<Text, IntWritable, Text, IntWritable> { @Override protected void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { // TODO Auto-generated method stub } } // step 3: Driver ,component job, implements Tool public int run(String[] args) throws Exception { // 1: get configration Configuration configuration = getConf(); // 2: create Job Job job = Job.getInstance(configuration, this.getClass() .getSimpleName()); // run jar job.setJarByClass(this.getClass()); // 3: set job // input -> map -> reduce -> output // 3.1 input Path inPath = new Path(args[0]); FileInputFormat.addInputPath(job, inPath); // 3.2: map job.setMapperClass(ModuleMapper.class); //TODO update paragram job.setMapOutputKeyClass(Text.class); job.setMapOutputValueClass(IntWritable.class); // 3.3: reduce job.setReducerClass(ModuleReducer.class); //TODO job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); // 3.4: output Path outPath = new Path(args[1]); FileOutputFormat.setOutputPath(job, outPath); // 4: submit job boolean isSuccess = job.waitForCompletion(true); return isSuccess ? 0 : 1; } // step 4: run program public static void main(String[] args) throws Exception { // 1: get configration Configuration configuration = new Configuration(); // int status = new moduleMapReduce().run(args); int status = ToolRunner.run(configuration, new moduleMapReduce(), args); System.exit(status); } }
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