webhdfs()

Read(214) Label: file data, upload, download,

Description:

Implement an operation on file data, such as download and upload.

Syntax:

webhdfs(url,localFile)

Note:

The external library function implements any operations within HDFS and WebHDFS.

Parameter:

url

URL of the target file

localFile

The target file; can be omitted

Return value:

Operation successful or failed

Example:

 

A

 

1

=webhdfs("http://localhost:50070/webhdfs/v1/test/z1.zip?op=CREATE&user.name=root","D:/z1.zip")

Upload folder D:/z1.zip

2

=webhdfs("http://localhost:50070/webhdfs/v1/test/f2.png?op=CREATE&user.name=root&overwrite=true","

D:/f2.png")

Upload folder D:/f2.png, and force an overwriting when a namesake folder already exists

3

=webhdfs("http://localhost:50070/webhdfs/v1/test/f3.txt?op=APPEND&user.name=root","D:/f4.txt")

Append data in D:/f4.txt to f3.txt

4

=webhdfs("http://localhost:50070/webhdfs/v1/test/f5.xlsx?op=OPEN&user.name=root","D:/f5.xlsx")

Download f5.xlsx

5

=webhdfs("http://localhost:50070/webhdfs/v1/test/?op=LISTSTATUS&user.name=root")

Get a list of files under /test/ directory and return result as a JSON string

6

=json(A5)

Convert A5’s JSON string into a multilevel, nested table sequence

7

=A6.FileStatuses.FileStatus

List detailed information of the files

 webhdfs_file()

Description:

Implement file read and write.

Syntax:

webhdfs_file(fileUrl,params)

Note:

The external library function implements file read and write using the HTTP request.

Parameter:

fileUrl

URL of the target file

params

Parameter in the file URL

Return value:

URL of the target file

Example:

 

A

 

1

=webhdfs_file("http://localhost:50070/webhdfs/v1/test/orders.txt":"UTF-8","user.name=root")

Connect to WebHDFS

2

=A1.read()

Read data from A1’s text file as a string

3

=A1.import@t()

Read content of the text file as records to form a table sequence to return

4

=A1.cursor().fetch ()

Create cursor for A1’s text file, and fetch records from the cursor

5

=webhdfs_file("http://localhost:50070/webhdfs/v1/test/orders.btx","user.name=root")

 

 

6

=A5.import@b()

Read content of A5’s bin file as records to form a table sequence to return

7

=A5.cursor@b().fetch()

Create cursor for A5’s bin file, and fetch records from the cursor