Java tutorial
/** * 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.hive.hbase; import java.io.IOException; import java.io.InterruptedIOException; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.Properties; import java.util.SortedMap; import java.util.TreeMap; import org.apache.commons.lang.NotImplementedException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CellComparator; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.KeyValueUtil; import org.apache.hadoop.hbase.io.ImmutableBytesWritable; import org.apache.hadoop.hbase.mapreduce.HFileOutputFormat; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.hive.common.FileUtils; import org.apache.hadoop.hive.ql.exec.FileSinkOperator.RecordWriter; import org.apache.hadoop.hive.ql.io.HiveOutputFormat; import org.apache.hadoop.hive.shims.ShimLoader; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.Writable; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.Progressable; /** * HiveHFileOutputFormat implements HiveOutputFormat for HFile bulk * loading. Until HBASE-1861 is implemented, it can only be used * for loading a table with a single column family. */ public class HiveHFileOutputFormat extends HFileOutputFormat implements HiveOutputFormat<ImmutableBytesWritable, KeyValue> { public static final String HFILE_FAMILY_PATH = "hfile.family.path"; static final Logger LOG = LoggerFactory.getLogger(HiveHFileOutputFormat.class.getName()); private org.apache.hadoop.mapreduce.RecordWriter<ImmutableBytesWritable, KeyValue> getFileWriter( org.apache.hadoop.mapreduce.TaskAttemptContext tac) throws IOException { try { return super.getRecordWriter(tac); } catch (InterruptedException ex) { throw new IOException(ex); } } /** * Retrieve the family path, first check the JobConf, then the table properties. * @return the family path or null if not specified. */ public static String getFamilyPath(Configuration jc, Properties tableProps) { return jc.get(HFILE_FAMILY_PATH, tableProps.getProperty(HFILE_FAMILY_PATH)); } @Override public RecordWriter getHiveRecordWriter(final JobConf jc, final Path finalOutPath, Class<? extends Writable> valueClass, boolean isCompressed, Properties tableProperties, final Progressable progressable) throws IOException { // Read configuration for the target path, first from jobconf, then from table properties String hfilePath = getFamilyPath(jc, tableProperties); if (hfilePath == null) { throw new RuntimeException("Please set " + HFILE_FAMILY_PATH + " to target location for HFiles"); } // Target path's last component is also the column family name. final Path columnFamilyPath = new Path(hfilePath); final String columnFamilyName = columnFamilyPath.getName(); final byte[] columnFamilyNameBytes = Bytes.toBytes(columnFamilyName); final Job job = new Job(jc); setCompressOutput(job, isCompressed); setOutputPath(job, finalOutPath); // Create the HFile writer final org.apache.hadoop.mapreduce.TaskAttemptContext tac = ShimLoader.getHadoopShims() .newTaskAttemptContext(job.getConfiguration(), progressable); final Path outputdir = FileOutputFormat.getOutputPath(tac); final Path taskAttemptOutputdir = new FileOutputCommitter(outputdir, tac).getWorkPath(); final org.apache.hadoop.mapreduce.RecordWriter<ImmutableBytesWritable, KeyValue> fileWriter = getFileWriter( tac); // Individual columns are going to be pivoted to HBase cells, // and for each row, they need to be written out in order // of column name, so sort the column names now, creating a // mapping to their column position. However, the first // column is interpreted as the row key. String columnList = tableProperties.getProperty("columns"); String[] columnArray = columnList.split(","); final SortedMap<byte[], Integer> columnMap = new TreeMap<byte[], Integer>(Bytes.BYTES_COMPARATOR); int i = 0; for (String columnName : columnArray) { if (i != 0) { columnMap.put(Bytes.toBytes(columnName), i); } ++i; } return new RecordWriter() { @Override public void close(boolean abort) throws IOException { try { fileWriter.close(null); if (abort) { return; } // Move the hfiles file(s) from the task output directory to the // location specified by the user. FileSystem fs = outputdir.getFileSystem(jc); fs.mkdirs(columnFamilyPath); Path srcDir = taskAttemptOutputdir; for (;;) { FileStatus[] files = fs.listStatus(srcDir, FileUtils.STAGING_DIR_PATH_FILTER); if ((files == null) || (files.length == 0)) { throw new IOException("No family directories found in " + srcDir); } if (files.length != 1) { throw new IOException("Multiple family directories found in " + srcDir); } srcDir = files[0].getPath(); if (srcDir.getName().equals(columnFamilyName)) { break; } if (files[0].isFile()) { throw new IOException("No family directories found in " + taskAttemptOutputdir + ". " + "The last component in hfile path should match column family name " + columnFamilyName); } } for (FileStatus regionFile : fs.listStatus(srcDir, FileUtils.STAGING_DIR_PATH_FILTER)) { fs.rename(regionFile.getPath(), new Path(columnFamilyPath, regionFile.getPath().getName())); } // Hive actually wants a file as task output (not a directory), so // replace the empty directory with an empty file to keep it happy. fs.delete(taskAttemptOutputdir, true); fs.createNewFile(taskAttemptOutputdir); } catch (InterruptedException ex) { throw new IOException(ex); } } private void writeText(Text text) throws IOException { // Decompose the incoming text row into fields. String s = text.toString(); String[] fields = s.split("\u0001"); assert (fields.length <= (columnMap.size() + 1)); // First field is the row key. byte[] rowKeyBytes = Bytes.toBytes(fields[0]); // Remaining fields are cells addressed by column name within row. for (Map.Entry<byte[], Integer> entry : columnMap.entrySet()) { byte[] columnNameBytes = entry.getKey(); int iColumn = entry.getValue(); String val; if (iColumn >= fields.length) { // trailing blank field val = ""; } else { val = fields[iColumn]; if ("\\N".equals(val)) { // omit nulls continue; } } byte[] valBytes = Bytes.toBytes(val); KeyValue kv = new KeyValue(rowKeyBytes, columnFamilyNameBytes, columnNameBytes, valBytes); try { fileWriter.write(null, kv); } catch (IOException e) { LOG.error("Failed while writing row: " + s); throw e; } catch (InterruptedException ex) { throw new IOException(ex); } } } private void writePut(PutWritable put) throws IOException { ImmutableBytesWritable row = new ImmutableBytesWritable(put.getPut().getRow()); SortedMap<byte[], List<Cell>> cells = put.getPut().getFamilyCellMap(); for (Map.Entry<byte[], List<Cell>> entry : cells.entrySet()) { Collections.sort(entry.getValue(), new CellComparator()); for (Cell c : entry.getValue()) { try { fileWriter.write(row, KeyValueUtil.copyToNewKeyValue(c)); } catch (InterruptedException e) { throw (InterruptedIOException) new InterruptedIOException().initCause(e); } } } } @Override public void write(Writable w) throws IOException { if (w instanceof Text) { writeText((Text) w); } else if (w instanceof PutWritable) { writePut((PutWritable) w); } else { throw new IOException("Unexpected writable " + w); } } }; } @Override public void checkOutputSpecs(FileSystem ignored, JobConf jc) throws IOException { //delegate to the new api Job job = new Job(jc); JobContext jobContext = ShimLoader.getHadoopShims().newJobContext(job); checkOutputSpecs(jobContext); } @Override public org.apache.hadoop.mapred.RecordWriter<ImmutableBytesWritable, KeyValue> getRecordWriter( FileSystem ignored, JobConf job, String name, Progressable progress) throws IOException { throw new NotImplementedException("This will not be invoked"); } }