The difference between HSSF,XSSF and SXSSF

HSSF is a pure Java implementation of POI Engineering for Excel 97 (-2007) file Operations
XSSF is a pure Java implementation of the POI Project for Excel OOXML (. xlsx) file Operations

starting with the POI 3.8 release, a low-memory-based API for XSSF is provided----SXSSF

SXSSF has a sliding window to limit access to the number of rows to reach a low memory footprint, and XSSF can access all lines. The old row data no longer appears in the sliding window and becomes inaccessible while writing to disk.
in Auto-refresh mode, you can specify the number of Access row in the window to maintain a certain number of row in memory. When this quantity is reached, the new row data is generated in the window and the low-index data is moved from the window to the disk.
Alternatively, the number of rows in the sliding window can be set to automatically grow. It can be modified according to a definite flushrow (int keeprows) call based on the desired period.

Note: For SXSSF Beta 3.8, there will be temporary files generated, such as:
Poi-sxssf-sheet4654655121378979321.xml
File Location: Java.io.tmpdir location under this environment variable
Under Windows 7 is C:\Users\xxxxxAppData\Local\Temp
Under Linux is/var/tmp/
Depending on the actual situation, see if you want to delete these temporary files

The official also offers some solutions:
https://issues.apache.org/bugzilla/show_bug.cgi?id=53493

comparison with the XSSF
at a point in time, only a certain amount of data can be accessed
no longer supports Sheet.clone ()
formulas are no longer supported for evaluation



Feature Summary

The difference between HSSF,XSSF and SXSSF