hadoop TopN
作者:互联网
1.Mysort
package s27;
import org.apache.hadoop.io.IntWritable;
public class MySort extends IntWritable.Comparator {
@Override
public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
//jiangxu
return -super.compare(b1, s1, l1, b2, s2, l2);
}
}
2.MyMap
package s27;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;
public class MyMap extends Mapper<LongWritable,Text,IntWritable,Text> {
IntWritable ha_numReal=new IntWritable();
Text ha_name=new Text();
@Override
protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
//super.map(key, value, context);
String line = value.toString();
String[] info = line.split(" ");
String name=info[0];
String num = info[1];
//String --> int
int numReal = Integer.parseInt(num);
//java --> hadoop
ha_numReal.set(numReal);
ha_name.set(name);
context.write(ha_numReal,ha_name);
}
}
3.MyRed
package s27;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import java.io.IOException;
public class MyRed extends Reducer<IntWritable,Text,IntWritable,Text> {
int count=0;
@Override
protected void reduce(IntWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
for (Text t :values){
//1. if>=3
if (count>=3){
break;
}
context.write(key,t);
count++;
}
}
}
4.MyJob
标签:int,hadoop,TopN,io,org,apache,import 来源: https://www.cnblogs.com/Song-wei/p/14010912.html