InverseMapper.java
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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.map;
- import java.io.IOException;
- import org.apache.hadoop.mapreduce.Mapper;
- /** A {@link Mapper} that swaps keys and values. */
- public class InverseMapper<K, V> extends Mapper<K,V,V,K> {
- /** The inverse function. Input keys and values are swapped.*/
- @Override
- public void map(K key, V value, Context context
- ) throws IOException, InterruptedException {
- context.write(value, key);
- }
-
- }