ZK Spreadsheet Essentials/FAQ

What is the maximal rows and columns ZSS supports?

ZSS doesn't render all cells to a browser, but it loads a file's whole content into memory. So basically the maximal rows and columns it supports depend on your server's memory. But even if you have sufficient memory, loading time could be an issue. Because loading time grows linearly with cell number. Under our test machine, if loading 1 million cells with a text takes 65 seconds, loading 2 million cells takes 139 seconds, and loading 4 million cells takes 315 seconds. The time could be too long to be acceptable by users. You can measure the loading time on your machine first.

Does ZSS support user permission control?

No. User permission feature involves authentication and authorization which is out of ZSS function's scope. Since ZSS cannot identify a user, it cannot assign a user with corresponding permissions. But you can easily integrate existing framework like Spring Security and implement your user permission features with ZSS. Please refer to the following sections:

• Hide the toolbar and the context menu to prevent editing. Please refer to ZK Spreadsheet Essentials/Working with Spreadsheet/Control Components.
• Disable available functions for different users. Please refer to ZK Spreadsheet Essentials/Working with Spreadsheet/Advanced/Disable Functions.
• Protect sheets and set available actions. Refer to Range.protectSheet(String, boolean, boolean, boolean, boolean, boolean, boolean, boolean, boolean, boolean, boolean, boolean allowSorting, boolean, boolean, boolean, boolean)

You can see an example at Working with Spreadsheet/Use Case/User Permission.

How do I save the content of ZSS or even save it to a database?

To save the content of ZSS, we recommend to export it as an Excel file instead of saving it rows by rows. It is also the way we implement the "Save" function in zssapp. After exporting, you can save the file into a BLOB type column of a database.

• How to export: Export to Excel
• Integrate custom saving process to ZSS toolbar's Save button: Toolbar Customization

After exporting to a PDF file, the PDF shows unexpected fonts or has missing characters

There are many reasons, but we list the most possible ones:

• You choose a wrong encoding for some characters.

For example, you apply "Calibri" on a Chinese character. You can resolve it by applying the correct font.

• The computer of your PDF viewer software doesn't install corresponding fonts.

For ZSS doesn't embed fonts into a exported PDF file, your computer should install the corresponding fonts to display the file correctly. You can test it by opening the PDF file in another computer or different OS. Please check installed fonts on your computer. Installing missing fonts can solve this problem.

The ZSS bundled iText will find fonts from the following paths. Please check the fonts you apply are available in these paths: Won't scan its subdirectories

   c:/windows/fonts
   c:/winnt/fonts
   d:/windows/fonts
   d:/winnt/fonts
   /Library/Fonts
   /System/Library/Fonts

Will scan its subdirectories

   /usr/share/X11/fonts
   /usr/X/lib/X11/fonts
   /usr/openwin/lib/X11/fonts    
   /usr/share/fonts
   /usr/X11R6/lib/X11/fonts

Extracted from FontFactoryImp com.lowagie.text.FontFactoryImp.

• The server to export a PDF doesn't install corresponding fonts.

It might happen when you export a PDF on a Linux server without Microsoft fonts installed. (Unbuntu should install the package ttf-mscorefonts-installer, "installer for Microsoft TrueType core fonts"). You will find the exported PDF's size is smaller than the one exported correctly. Install the corresponding fonts can solve this issue.

How do I know my file can be loaded correctly by ZSS?

In general, those functions we implement with the toolbar are supported. However, the best way is to upload your files to the ZK Spreadsheet EE Demo App. It's a ready-to-use web application based on ZSS component. You just run the war with a Java application server, then you can upload files via the menu, File / Open / Upload.

Does ZSS support VB macro?

No. Even Microsoft Excel online doesn't support running VB macro. But you can port your macro to Java within a controller to achieve the same function.

All source code listed in this book is at Github.