hadoop AutoInputFormat 源码
haddop AutoInputFormat 代码
文件路径：/hadoop-tools/hadoop-streaming/src/main/java/org/apache/hadoop/streaming/AutoInputFormat.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.streaming;
import java.io.EOFException;
import java.io.IOException;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.hadoop.mapred.TextInputFormat;
/**
* An {@link InputFormat} that tries to deduce the types of the input files
* automatically. It can currently handle text and sequence files.
*/
public class AutoInputFormat extends FileInputFormat {
private TextInputFormat textInputFormat = new TextInputFormat();
private SequenceFileInputFormat seqFileInputFormat =
new SequenceFileInputFormat();
public void configure(JobConf job) {
textInputFormat.configure(job);
// SequenceFileInputFormat has no configure() method
}
public RecordReader getRecordReader(InputSplit split, JobConf job,
Reporter reporter) throws IOException {
FileSplit fileSplit = (FileSplit) split;
FileSystem fs = FileSystem.get(fileSplit.getPath().toUri(), job);
FSDataInputStream is = fs.open(fileSplit.getPath());
byte[] header = new byte[3];
RecordReader reader = null;
try {
is.readFully(header);
} catch (EOFException eof) {
reader = textInputFormat.getRecordReader(split, job, reporter);
} finally {
is.close();
}
if (header[0] == 'S' && header[1] == 'E' && header[2] == 'Q') {
reader = seqFileInputFormat.getRecordReader(split, job, reporter);
} else {
reader = textInputFormat.getRecordReader(split, job, reporter);
}
return reader;
}
}
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