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Does ZSS support user permission control?

We provide API for you to build your owned permission control. 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:

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.

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


Will scan its subdirectories


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 (or here). The macro in a file will be lost after being imported since ZSS doesn't keep the macro information.

If you need something similar, you can port your macro to Java within a controller to achieve the same function.

How to validate an XLSX format Excel file

Validate it with Open XML SDK 2.5 Productivity Tool for Microsoft Office.

Run out of heap when exporting / importing a large file

You might encounter an error like java.lang.OutOfMemoryError: Java heap space when exporting / importing a large file, since it consumes more memory at that process. Please increase your JVM heap size. (You can refer to Java HotSpot VM Heap Size Options)

What is the maximal rows and columns ZSS supports?

  • The max column is 16384 (2^14)
  • the max row is 1048576 (2^20)

ZSS renders cells on demand instead of rendering all cells at once in a browser, but it loads a file's whole content into the memory. So the bigger memory your server has, the more rows and columns ZSS can load.

Even if you have sufficient memory, loading time could be an issue. Because loading time grows linearly with cell number. Under our test machine, loading 1 million cells with texts takes 65 seconds, loading 2 million cells takes 139 seconds and loading 4 million cells takes 315 seconds. As the cell number grows, the time could be too long to be acceptable by users. You can measure the loading time on your machine first.

Does ZSS support form control like the menu in Excel, Developer > Form Controls?

No. But there are several alternatives:

  • Use ZK menu.

Please refer to the menu on top of ZSS at ZSS demo

  • Create a custom context menu.

Please refer to Custom Context Menu

  • Insert special symbols in cells to simulate a checkbox, button.

You can insert icon-like symbols in a cell, so users think that cell is a button like below:


Then you can determine these cells in an event listener and perform your business logic.

  • Data validation can produce a dropdown list

Please refer to Data Validation

  • Show a component on a cell with a popup.

Unable to get property 'appendCell' of undefined or null reference in IE

If you visit with IE11 and see such error message in developer tool's console. This is mostly caused by compatibility mode. Please turn it off and reload the page again since ZK/ZSS don't support such mode.

All source code listed in this book is at Github.

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.