ExternalMapperReducer.java
上传用户:quxuerui
上传日期:2018-01-08
资源大小:41811k
文件大小:2k
- /**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package testjar;
- import java.io.IOException;
- import java.util.Iterator;
- import org.apache.hadoop.io.IntWritable;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.io.Writable;
- import org.apache.hadoop.io.WritableComparable;
- import org.apache.hadoop.mapred.JobConf;
- import org.apache.hadoop.mapred.Mapper;
- import org.apache.hadoop.mapred.OutputCollector;
- import org.apache.hadoop.mapred.Reducer;
- import org.apache.hadoop.mapred.Reporter;
- public class ExternalMapperReducer
- implements Mapper<WritableComparable, Writable,
- ExternalWritable, IntWritable>,
- Reducer<WritableComparable, Writable,
- WritableComparable, IntWritable> {
- public void configure(JobConf job) {
- }
- public void close()
- throws IOException {
- }
- public void map(WritableComparable key, Writable value,
- OutputCollector<ExternalWritable, IntWritable> output,
- Reporter reporter)
- throws IOException {
-
- if (value instanceof Text) {
- Text text = (Text)value;
- ExternalWritable ext = new ExternalWritable(text.toString());
- output.collect(ext, new IntWritable(1));
- }
- }
- public void reduce(WritableComparable key, Iterator<Writable> values,
- OutputCollector<WritableComparable, IntWritable> output,
- Reporter reporter)
- throws IOException {
-
- int count = 0;
- while (values.hasNext()) {
- count++;
- values.next();
- }
- output.collect(key, new IntWritable(count));
- }
- }