利用MapReduce分析微博粉丝数

import java.io.IOException;


import java.util.HashMap;
import java.util.Map;
import java.util.Set;


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.filecache.DistributedCache;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;


public class Weibo {
public static class weiboMapper extends Mapper<Object, Text, Text, IntWritable>{
@Override
protected void map(Object key, Text value, Mapper<Object, Text, Text, IntWritable>.Context context)
throws IOException, InterruptedException {
// TODO Auto-generated method stub
String[] strings = value.toString().split("\t");
if (strings.length == 5) {
String name = strings[0];
int fans = Integer.parseInt(strings[2]);
context.write(new Text(name),new IntWritable(fans));
}
}
}
public static class weiboReducer extends Reducer<Text, IntWritable, Text, IntWritable>{
Map<String, Integer> map = new HashMap<>();
@Override
protected void reduce(Text name, Iterable<IntWritable> fans,
Reducer<Text, IntWritable, Text, IntWritable>.Context context) throws IOException, InterruptedException {
// TODO Auto-generated method stub
for (IntWritable intWritable : fans) {
map.put(name.toString(), Integer.parseInt(intWritable.toString()));
}
}
@Override
protected void cleanup(Reducer<Text, IntWritable, Text, IntWritable>.Context context)
throws IOException, InterruptedException {
// TODO Auto-generated method stub
Set<String> set = map.keySet();
for(int i =0;i<5;i++){
int a = 0;
String nString = "";
for (String name : set) {
if (map.get(name)>a) {
nString = name;
a = map.get(name);
}
}
context.write(new Text(nString), new IntWritable(a));
map.remove(nString);
}
}
}
public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
Job job = Job.getInstance(new Configuration());
job.setJarByClass(Weibo.class);
job.setMapperClass(weiboMapper.class);
job.setReducerClass(weiboReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.waitForCompletion(true);
}

}