Spark iterate HDFS directory

问题:

I have a directory of directories on HDFS, and I want to iterate over the directories. Is there any easy way to do this with Spark using the SparkContext object?

回答1:

You can use org.apache.hadoop.fs.FileSystem. Specifically, FileSystem.listFiles([path], true)

And with Spark...

FileSystem.get(sc.hadoopConfiguration()).listFiles(..., true)

Edit

It's worth noting that good practice is to get the FileSystem that is associated with the Path's scheme.

path.getFileSystem(sc.hadoopConfiguration).listFiles(path, true)

回答2:

Here's PySpark version if someone is interested:

hadoop = sc._jvm.org.apache.hadoop

fs = hadoop.fs.FileSystem
conf = hadoop.conf.Configuration() 
path = hadoop.fs.Path('/hivewarehouse/disc_mrt.db/unified_fact/')

for f in fs.get(conf).listStatus(path):
    print f.getPath()

In this particular case I get list of all files that make up disc_mrt.unified_fact Hive table.

Other methods of FileStatus object, like getLen() to get file size are described here:

Class FileStatus

回答3:

import  org.apache.hadoop.fs.{FileSystem,Path}

FileSystem.get( sc.hadoopConfiguration ).listStatus( new Path("hdfs:///tmp")).foreach( x => println(x.getPath ))

This worked for me.

Spark version 1.5.0-cdh5.5.2

回答4:

this did the job for me

FileSystem.get(new URI("hdfs://HAservice:9000"), sc.hadoopConfiguration).listStatus( new Path("/tmp/")).foreach( x => println(x.getPath ))

回答5:

You can try with globStatus status as well

val listStatus = org.apache.hadoop.fs.FileSystem.get(new URI(url), sc.hadoopConfiguration).globStatus(new org.apache.hadoop.fs.Path(url))

      for (urlStatus <- listStatus) {
        println("urlStatus get Path:"+urlStatus.getPath())
}

回答6:

@Tagar didn't say how to connect remote hdfs, but this answer did:

URI           = sc._gateway.jvm.java.net.URI
Path          = sc._gateway.jvm.org.apache.hadoop.fs.Path
FileSystem    = sc._gateway.jvm.org.apache.hadoop.fs.FileSystem
Configuration = sc._gateway.jvm.org.apache.hadoop.conf.Configuration


fs = FileSystem.get(URI("hdfs://somehost:8020"), Configuration())

status = fs.listStatus(Path('/some_dir/yet_another_one_dir/'))

for fileStatus in status:
    print(fileStatus.getPath())