scala - 如何在 Apache Spark scala 中读取 PDF 文件和 xml 文件？

Question

我读取文本文件的示例代码是

val text = sc.hadoopFile(path, classOf[TextInputFormat], classOf[LongWritable], classOf[Text], sc.defaultMinPartitions)
    var rddwithPath = text.asInstanceOf[HadoopRDD[LongWritable, Text]].mapPartitionsWithInputSplit { (inputSplit, iterator) ⇒
      val file = inputSplit.asInstanceOf[FileSplit]
      iterator.map { tpl ⇒ (file.getPath.toString, tpl._2.toString) }
    }.reduceByKey((a,b) => a)

这样我如何使用PDF和Xml文件

Answer 1

可以使用 Tika 解析 PDF 和 XML:

看 Apache Tika - a content analysis toolkit

看着
- https://tika.apache.org/1.9/api/org/apache/tika/parser/xml/
- http://tika.apache.org/0.7/api/org/apache/tika/parser/pdf/PDFParser.html
- https://tika.apache.org/1.9/api/org/apache/tika/parser/AutoDetectParser.html
下面是 Spark 与 Tika 的集成示例:

import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
import org.apache.spark.SparkConf
import org.apache.spark.input.PortableDataStream
import org.apache.tika.metadata._
import org.apache.tika.parser._
import org.apache.tika.sax.WriteOutContentHandler
import java.io._

object TikaFileParser {

  def tikaFunc (a: (String, PortableDataStream)) = {

    val file : File = new File(a._1.drop(5))
    val myparser : AutoDetectParser = new AutoDetectParser()
    val stream : InputStream = new FileInputStream(file)
    val handler : WriteOutContentHandler = new WriteOutContentHandler(-1)
    val metadata : Metadata = new Metadata()
    val context : ParseContext = new ParseContext()

    myparser.parse(stream, handler, metadata, context)

    stream.close

    println(handler.toString())
    println("------------------------------------------------")
  }


  def main(args: Array[String]) {

    val filesPath = "/home/user/documents/*"
    val conf = new SparkConf().setAppName("TikaFileParser")
    val sc = new SparkContext(conf)
    val fileData = sc.binaryFiles(filesPath)
    fileData.foreach( x => tikaFunc(x))
  }
}