如何防止hadoop的hdfsapi创建父目录?

weylhg0b  于 2021-05-29  发布在  Hadoop
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如果生成子目录时父目录不存在,我希望hdfs命令失败。当我使用 FileSystem#mkdirs ,我发现没有出现异常,而是创建了不存在的父目录:

import java.util.UUID
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.{FileSystem, Path}

val conf = new Configuration()
conf.set("fs.defaultFS", s"hdfs://$host:$port")

val fileSystem = FileSystem.get(conf)
val cwd = fileSystem.getWorkingDirectory

// Guarantee non-existence by appending two UUIDs.
val dirToCreate = new Path(cwd, new Path(UUID.randomUUID.toString, UUID.randomUUID.toString))

fileSystem.mkdirs(dirToCreate)

如果没有检查是否存在的繁琐负担,如果父目录不存在,如何强制hdfs抛出异常?

y53ybaqx

y53ybaqx1#

文件系统api不支持这种行为。相反, FileContext#mkdir 应使用;例如:

import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.{FileContext, FileSystem, Path}
import org.apache.hadoop.fs.permission.FsPermission

val files = FileContext.getFileContext()
val cwd = files.getWorkingDirectory
val permissions = new FsPermission("644")
val createParent = false

// Guarantee non-existence by appending two UUIDs.
val dirToCreate = new Path(cwd, new Path(UUID.randomUUID.toString, UUID.randomUUID.toString))

files.mkdir(dirToCreate, permissions, createParent)

上面的示例将抛出:

java.io.FileNotFoundException: Parent directory doesn't exist: /user/erip/f425a2c9-1007-487b-8488-d73d447c6f79

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