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 gobblin.compaction.hive; import java.io.IOException; import java.util.Set; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.base.Strings; /** * Management for HDFS reads and writes. */ public abstract class HdfsIO { private static final Logger LOG = LoggerFactory.getLogger(HdfsIO.class); private static final String HDFS_URI = "hdfs.uri"; private static final String HDFS_URI_DEFAULT = "hdfs://localhost:9000"; private static final String HADOOP_CONFIGFILE_ = "hadoop.configfile."; private static final String HDFS_URI_HADOOP = "fs.defaultFS"; @Deprecated // Gobblin only supports Hadoop 2.x.x private static final String HADOOP_VERSION = "hadoop.version"; protected final String filePathInHdfs; protected final FileSystem fileSystem; public HdfsIO(String filePathInHdfs) throws IOException { this.filePathInHdfs = filePathInHdfs; this.fileSystem = getFileSystem(); } protected static FileSystem getFileSystem() throws IOException { Configuration conf = getConfiguration(); return FileSystem.get(conf); } protected static Configuration getConfiguration() { Configuration conf = new Configuration(); addResourceToConf(conf); return conf; } private static void addResourceToConf(Configuration conf) { addHadoopConfigPropertiesToConf(conf); if (CompactionRunner.properties.containsKey(HDFS_URI)) { conf.set(HDFS_URI_HADOOP, CompactionRunner.properties.getProperty(HDFS_URI)); } if (Strings.isNullOrEmpty(conf.get(HDFS_URI_HADOOP))) { conf.set(HDFS_URI_HADOOP, HDFS_URI_DEFAULT); } CompactionRunner.properties.setProperty(HDFS_URI, conf.get(HDFS_URI_HADOOP)); } private static void addHadoopConfigPropertiesToConf(Configuration conf) { Set<String> propertyNames = CompactionRunner.properties.stringPropertyNames(); for (String propertyName : propertyNames) { if (propertyName.startsWith(HADOOP_CONFIGFILE_)) { String hadoopConfigFile = CompactionRunner.properties.getProperty(propertyName); conf.addResource(new Path(hadoopConfigFile)); LOG.info("Added Hadoop Config File: " + hadoopConfigFile); } } } public static String getHdfsUri() { return CompactionRunner.properties.getProperty(HDFS_URI, HDFS_URI_DEFAULT); } }