LongSumReducer.java
上传用户:quxuerui
上传日期:2018-01-08
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文件大小:1k
- /**
- * 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 org.apache.hadoop.mapreduce.lib.reduce;
- import java.io.IOException;
- import org.apache.hadoop.io.LongWritable;
- import org.apache.hadoop.mapreduce.Reducer;
- public class LongSumReducer<KEY> extends Reducer<KEY, LongWritable,
- KEY,LongWritable> {
- private LongWritable result = new LongWritable();
- public void reduce(KEY key, Iterable<LongWritable> values,
- Context context) throws IOException, InterruptedException {
- long sum = 0;
- for (LongWritable val : values) {
- sum += val.get();
- }
- result.set(sum);
- context.write(key, result);
- }
- }