StreamInputFormat.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.streaming;
- import java.io.*;
- import java.lang.reflect.*;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.FSDataInputStream;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.mapred.*;
- /** An input format that selects a RecordReader based on a JobConf property.
- * This should be used only for non-standard record reader such as
- * StreamXmlRecordReader. For all other standard
- * record readers, the appropriate input format classes should be used.
- */
- public class StreamInputFormat extends KeyValueTextInputFormat {
- @SuppressWarnings("unchecked")
- public RecordReader<Text, Text> getRecordReader(final InputSplit genericSplit,
- JobConf job, Reporter reporter) throws IOException {
- String c = job.get("stream.recordreader.class");
- if (c == null || c.indexOf("LineRecordReader") >= 0) {
- return super.getRecordReader(genericSplit, job, reporter);
- }
- // handling non-standard record reader (likely StreamXmlRecordReader)
- FileSplit split = (FileSplit) genericSplit;
- LOG.info("getRecordReader start.....split=" + split);
- reporter.setStatus(split.toString());
- // Open the file and seek to the start of the split
- FileSystem fs = split.getPath().getFileSystem(job);
- FSDataInputStream in = fs.open(split.getPath());
- // Factory dispatch based on available params..
- Class readerClass;
- {
- readerClass = StreamUtil.goodClassOrNull(job, c, null);
- if (readerClass == null) {
- throw new RuntimeException("Class not found: " + c);
- }
- }
- Constructor ctor;
- try {
- ctor = readerClass.getConstructor(new Class[] { FSDataInputStream.class,
- FileSplit.class, Reporter.class, JobConf.class, FileSystem.class });
- } catch (NoSuchMethodException nsm) {
- throw new RuntimeException(nsm);
- }
- RecordReader<Text, Text> reader;
- try {
- reader = (RecordReader<Text, Text>) ctor.newInstance(new Object[] { in, split,
- reporter, job, fs });
- } catch (Exception nsm) {
- throw new RuntimeException(nsm);
- }
- return reader;
- }
- }