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java 中Spark中將對象序列化存儲到hdfs
摘要: Spark應用中經常會遇到這樣一個需求: 需要將JAVA對象序列化并存儲到HDFS, 尤其是利用MLlib計算出來的一些模型, 存儲到hdfs以便模型可以反復利用. 下面的例子演示了Spark環境下從Hbase讀取數據, 生成一個word2vec模型, 存儲到hdfs.
廢話不多說, 直接貼代碼了. spark1.4 + hbase0.98
import org.apache.spark.storage.StorageLevel import scala.collection.JavaConverters._ import java.io.File import java.io.FileInputStream import java.io.FileOutputStream import java.io.ObjectInputStream import java.io.ObjectOutputStream import java.net.URI import java.util.Date import org.ansj.library.UserDefineLibrary import org.ansj.splitWord.analysis.NlpAnalysis import org.ansj.splitWord.analysis.ToAnalysis import org.apache.hadoop.fs.FSDataInputStream import org.apache.hadoop.fs.FSDataOutputStream import org.apache.hadoop.fs.FileSystem import org.apache.hadoop.fs.FileUtil import org.apache.hadoop.fs.Path import org.apache.hadoop.hbase.client._ import org.apache.hadoop.hbase.{HBaseConfiguration, HTableDescriptor, TableName} import org.apache.hadoop.hbase.filter.FilterList import org.apache.hadoop.hbase.filter.PageFilter import org.apache.hadoop.hbase.filter.RegexStringComparator import org.apache.hadoop.hbase.filter.SingleColumnValueFilter import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp import org.apache.hadoop.hbase.mapreduce.TableInputFormat import org.apache.hadoop.hbase.protobuf.ProtobufUtil import org.apache.hadoop.hbase.util.{Base64, Bytes} import com.feheadline.fespark.db.Neo4jManager import com.feheadline.fespark.util.Env import org.apache.spark.SparkConf import org.apache.spark.SparkContext import org.apache.spark.rdd._ import org.apache.spark.mllib.feature.{Word2Vec, Word2VecModel} import scala.math.log import scala.io.Source object Word2VecDemo { def convertScanToString(scan: Scan) = { val proto = ProtobufUtil.toScan(scan) Base64.encodeBytes(proto.toByteArray) } def main(args: Array[String]): Unit = { val sparkConf = new SparkConf().setAppName("Word2Vec Demo") sparkConf.set("spark.serializer", "org.apache.spark.serializer.KryoSerializer") sparkConf.set("spark.kryoserializer.buffer", "256m") sparkConf.set("spark.kryoserializer.buffer.max","2046m") sparkConf.set("spark.akka.frameSize", "500") sparkConf.set("spark.rpc.askTimeout", "30") val sc = new SparkContext(sparkConf) val hbaseConf = HBaseConfiguration.create() hbaseConf.set("hbase.zookeeper.quorum", "myzookeeper") hbaseConf.set(TableInputFormat.INPUT_TABLE, "crawled") val scan = new Scan() val filterList:FilterList = new FilterList(FilterList.Operator.MUST_PASS_ALL) val comp:RegexStringComparator = new RegexStringComparator(""".{1500,}""") val articleFilter:SingleColumnValueFilter = new SingleColumnValueFilter( "data".getBytes, "article".getBytes, CompareOp.EQUAL, comp ) filterList.addFilter(articleFilter) filterList.addFilter(new PageFilter(100)) scan.setFilter(filterList) scan.setCaching(50) scan.setCacheBlocks(false) hbaseConf.set(TableInputFormat.SCAN,convertScanToString(scan)) val crawledRDD = sc.newAPIHadoopRDD( hbaseConf, classOf[TableInputFormat], classOf[org.apache.hadoop.hbase.io.ImmutableBytesWritable], classOf[org.apache.hadoop.hbase.client.Result] ) val articlesRDD = crawledRDD.filter{ case (_,result) => { val content = Bytes.toString(result.getValue("data".getBytes,"article".getBytes)) content != null } } val wordsInDoc = articlesRDD.map{ case (_,result) => { val content = Bytes.toString(result.getValue("data".getBytes,"article".getBytes)) if(content!=null)ToAnalysis.parse(content).asScala.map(_.getName).toSeq else Seq("") } } val fitleredWordsInDoc = wordsInDoc.filter(_.nonEmpty) val word2vec = new Word2Vec() val model = word2vec.fit(fitleredWordsInDoc) //---------------------------------------重點看這里------------------------------------------------------------- //將上面的模型存儲到hdfs val hadoopConf = sc.hadoopConfiguration hadoopConf.set("fs.defaultFS", "hdfs://myhadoop:9000/") val fileSystem = FileSystem.get(hadoopConf) val path = new Path("/user/hadoop/data/mllib/word2vec-object") val oos = new ObjectOutputStream(new FSDataOutputStream(fileSystem.create(path))) oos.writeObject(model) oos.close //這里示例另外一個程序直接從hdfs讀取序列化對象使用模型 val ois = new ObjectInputStream(new FSDataInputStream(fileSystem.open(path))) val sample_model = ois.readObject.asInstanceOf[Word2VecModel] /* * //你還可以將序列化文件從hdfs放到本地, scala程序使用模型 * import java.io._ * import org.apache.spark.mllib.feature.{Word2Vec, Word2VecModel} * val ois = new ObjectInputStream(new FileInputStream("/home/cherokee/tmp/word2vec-object")) * val sample_model = ois.readObject.asInstanceOf[Word2VecModel] * ois.close */ //-------------------------------------------------------------------------------------------------------------- } }
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