SequenceFileOutputFormat.java
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上传日期:2018-01-08
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- /**
- * 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.mapred;
- import java.io.IOException;
- import java.util.Arrays;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.Path;
- import org.apache.hadoop.fs.FileUtil;
- import org.apache.hadoop.io.SequenceFile;
- import org.apache.hadoop.io.SequenceFile.CompressionType;
- import org.apache.hadoop.io.compress.CompressionCodec;
- import org.apache.hadoop.io.compress.DefaultCodec;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.util.*;
- /** An {@link OutputFormat} that writes {@link SequenceFile}s.
- * @deprecated Use
- * {@link org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat}
- * instead.
- */
- @Deprecated
- public class SequenceFileOutputFormat <K,V> extends FileOutputFormat<K, V> {
- public RecordWriter<K, V> getRecordWriter(
- FileSystem ignored, JobConf job,
- String name, Progressable progress)
- throws IOException {
- // get the path of the temporary output file
- Path file = FileOutputFormat.getTaskOutputPath(job, name);
-
- FileSystem fs = file.getFileSystem(job);
- CompressionCodec codec = null;
- CompressionType compressionType = CompressionType.NONE;
- if (getCompressOutput(job)) {
- // find the kind of compression to do
- compressionType = getOutputCompressionType(job);
- // find the right codec
- Class<? extends CompressionCodec> codecClass = getOutputCompressorClass(job,
- DefaultCodec.class);
- codec = ReflectionUtils.newInstance(codecClass, job);
- }
- final SequenceFile.Writer out =
- SequenceFile.createWriter(fs, job, file,
- job.getOutputKeyClass(),
- job.getOutputValueClass(),
- compressionType,
- codec,
- progress);
- return new RecordWriter<K, V>() {
- public void write(K key, V value)
- throws IOException {
- out.append(key, value);
- }
- public void close(Reporter reporter) throws IOException { out.close();}
- };
- }
- /** Open the output generated by this format. */
- public static SequenceFile.Reader[] getReaders(Configuration conf, Path dir)
- throws IOException {
- FileSystem fs = dir.getFileSystem(conf);
- Path[] names = FileUtil.stat2Paths(fs.listStatus(dir));
-
- // sort names, so that hash partitioning works
- Arrays.sort(names);
-
- SequenceFile.Reader[] parts = new SequenceFile.Reader[names.length];
- for (int i = 0; i < names.length; i++) {
- parts[i] = new SequenceFile.Reader(fs, names[i], conf);
- }
- return parts;
- }
- /**
- * Get the {@link CompressionType} for the output {@link SequenceFile}.
- * @param conf the {@link JobConf}
- * @return the {@link CompressionType} for the output {@link SequenceFile},
- * defaulting to {@link CompressionType#RECORD}
- */
- public static CompressionType getOutputCompressionType(JobConf conf) {
- String val = conf.get("mapred.output.compression.type",
- CompressionType.RECORD.toString());
- return CompressionType.valueOf(val);
- }
-
- /**
- * Set the {@link CompressionType} for the output {@link SequenceFile}.
- * @param conf the {@link JobConf} to modify
- * @param style the {@link CompressionType} for the output
- * {@link SequenceFile}
- */
- public static void setOutputCompressionType(JobConf conf,
- CompressionType style) {
- setCompressOutput(conf, true);
- conf.set("mapred.output.compression.type", style.toString());
- }
- }