package ssdut.training.mapreduce.datecount; 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.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; public class DateGroup { public static class DateGroupMapper extends Mapper<Object, Text, Text, IntWritable> { public void map(Object key, Text value, Context context ) throws IOException, InterruptedException { String[] strs = value.toString().split(" "); //按空格分割输入 String date = strs[0]; //获取日期 int id = Integer.parseInt(strs[1]); //获取序号 context.write(new Text(date), new IntWritable(id)); } } public static class DateGroupReducer extends Reducer<Text,IntWritable,Text,Text> { public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { StringBuilder sb = new StringBuilder(); sb.append("[ "); for (IntWritable val : values) { //将value值串联 sb.append(val.toString()).append(" "); } sb.append("]"); context.write(key, new Text(sb.toString())); } } 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"); //2.设置MapReduce作业配置信息 String jobName = "DateGroup"; //作业名称 Job job = Job.getInstance(conf, jobName); job.setJarByClass(DateGroup.class); //指定运行时作业类 job.setJar("export\\DateGroup.jar"); //指定本地jar包 job.setMapperClass(DateGroupMapper.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(DateGroupReducer.class); //指定Reducer类 job.setOutputKeyClass(Text.class); //设置Reduce输出Key类型 job.setOutputValueClass(Text.class); //设置Reduce输出Value类型 //3.设置作业输入和输出路径 String dataDir = "/expr/datecount/data"; //实验数据目录 String outputDir = "/expr/datecount/output_group"; //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); } } }