Description:
Implement file read and write.
Syntax:
webhdfs_file(fileUrl,params)
Note:
The external library function (See External Library Guide) 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. |