Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package accesslog4; import java.io.IOException; import java.util.Scanner; import java.util.StringTokenizer; import java.util.regex.Pattern; import java.text.ParseException; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; 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.input.TextInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat; public class Accesslog4 { public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> { //private IntWritable hour = new IntWritable(); private final static IntWritable one = new IntWritable(1); private Text word = new Text(); private static Pattern logPattern = Pattern /*.compile("([^ ]*) ([^ ]*) ([^ ]*) \\[([^]]*)\\]" + " \"([^\"]*)\"" + " ([^ ]*) ([^ ]*).*");*/ .compile("%h %l %u %t \"%r\" %>s %b"); public void map(Object key, Text value, Context context) throws IOException, InterruptedException { String line = ((Text) value).toString(); Matcher matcher = logPattern.matcher(line); if (matcher.matches()) { String item = matcher.group(1); word.set(item); context.write(word, one); } } } public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> { //private IntWritable result = new IntWritable(); static int maximum = 0; Text pathmax = new Text(); public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } if (maximum < sum) { maximum = sum; pathmax.set(key); } //result.set(sum); //context.write(key, result); } public void cleanup(Context context) throws IOException, InterruptedException { context.write(pathmax, new IntWritable(maximum)); } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); Path inputPath = new Path(args[0]); Path outputPath = new Path(args[1]); Job job = Job.getInstance(conf, "Accesslog4"); job.setJarByClass(Accesslog4.class); job.setMapperClass(TokenizerMapper.class); job.setCombinerClass(IntSumReducer.class); job.setReducerClass(IntSumReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); FileInputFormat.addInputPath(job, inputPath); FileOutputFormat.setOutputPath(job, outputPath); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); System.exit(job.waitForCompletion(true) ? 0 : 1); } }