package ssdut.training.mapreduce.inputformat; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; 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.input.NLineInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; public class NLineInput { public static class NLineInputMapper extends Mapper<LongWritable, Text, Text, IntWritable> { private final static IntWritable one = new IntWritable(1); public void map(LongWritable key, Text value, Context context ) throws IOException, InterruptedException { System.out.println("value: "+value.toString()); String[] strs = value.toString().split(" "); System.out.println("NLines strs is:"+strs); System.out.println("strs[0]"+strs[0]); Text date = new Text(strs[0]); context.write(date, one); } } public static class NLineInputReducer extends Reducer<Text,IntWritable,Text,IntWritable> { public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } context.write(key, new IntWritable(sum)); } } public static void main(String[] args) throws Exception { //1.设置HDFS配置信息 String namenode_ip = "192.168.17.10"; String hdfs = "hdfs://" + namenode_ip + ":9000"; Configuration conf = new Configuration(); conf.set("fs.defaultFS", hdfs); conf.set("mapreduce.app-submission.cross-platform", "true"); conf.setInt("mapreduce.input.lineinputformat.linespermap", 1000); //设置每个Map处理的行数 //2.设置MapReduce作业配置信息 String jobName = "NLineInput"; //作业名称 Job job = Job.getInstance(conf, jobName); job.setJarByClass(NLineInput.class); //指定运行时作业类 job.setJar("export\\NLineInput.jar"); //指定本地jar包 job.setMapperClass(NLineInputMapper.class); //指定Mapper类 job.setMapOutputKeyClass(Text.class); //设置Mapper输出Key类型 job.setMapOutputValueClass(IntWritable.class); //设置Mapper输出Value类型 job.setReducerClass(NLineInputReducer.class); //指定Reducer类 job.setOutputKeyClass(Text.class); //设置Reduce输出Key类型 job.setOutputValueClass(IntWritable.class); //设置Reduce输出Value类型 job.setInputFormatClass(NLineInputFormat.class); //设置输入格式化类 //3.设置作业输入和输出路径 String dataDir = "/expr/nlineinput/data"; //实验数据目录 String outputDir = "/expr/nlineinput/output"; //实验输出目录 Path inPath = new Path(hdfs + dataDir); Path outPath = new Path(hdfs + outputDir); FileInputFormat.addInputPath(job, inPath); FileOutputFormat.setOutputPath(job, outPath); FileSystem fs = FileSystem.get(conf); if(fs.exists(outPath)) { fs.delete(outPath, true); } //4.运行作业 System.out.println("Job: " + jobName + " is running..."); if(job.waitForCompletion(true)) { System.out.println("success!"); System.exit(0); } else { System.out.println("failed!"); System.exit(1); } } }