hadoop KeyValueTextInputFormat 源码
haddop KeyValueTextInputFormat 代码
文件路径：/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/input/KeyValueTextInputFormat.java
/**
* 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.input;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.io.compress.SplittableCompressionCodec;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
/**
* An {@link InputFormat} for plain text files. Files are broken into lines.
* Either line feed or carriage-return are used to signal end of line.
* Each line is divided into key and value parts by a separator byte. If no
* such a byte exists, the key will be the entire line and value will be empty.
* The separator byte can be specified in config file under the attribute name
* mapreduce.input.keyvaluelinerecordreader.key.value.separator. The default
* is the tab character ('\t').
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class KeyValueTextInputFormat extends FileInputFormat<Text, Text> {
@Override
protected boolean isSplitable(JobContext context, Path file) {
final CompressionCodec codec =
new CompressionCodecFactory(context.getConfiguration()).getCodec(file);
if (null == codec) {
return true;
}
return codec instanceof SplittableCompressionCodec;
}
public RecordReader<Text, Text> createRecordReader(InputSplit genericSplit,
TaskAttemptContext context) throws IOException {
context.setStatus(genericSplit.toString());
return new KeyValueLineRecordReader(context.getConfiguration());
}
}
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