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Discover how to effectively format numbers in JSF using p:outputLabel to avoid the scientific notation problem.
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This video is based on the question https://stackoverflow.com/q/76165047/ asked by the user 'Владимир Царьков' ( https://stackoverflow.com/u/17084265/ ) and on the answer https://stackoverflow.com/a/76166627/ provided by the user 'Jasper de Vries' ( https://stackoverflow.com/u/880619/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Properly Format a Number in JSF with p:outputLabel

When working with JSF and data binding, you might encounter a situation where you need to display numerical values clearly and effectively. For instance, if you have a property that holds a numeric value, displaying it directly can sometimes lead to unexpected results, like scientific notation. This common issue often arises when using p:outputLabel, which is designed to output labels in a user-friendly manner.

In this guide, we'll address a specific problem: how to format a number correctly when it's part of the value of p:outputLabel. We'll break down the solution into clear, actionable steps.

Understanding the Problem

Let’s say you have the following JSF code snippet:

[[See Video to Reveal this Text or Code Snippet]]

Here, Myclass.current.amount is a double value in Java. When this amount equals 10000000, instead of seeing a clear representation of that number, you might observe it displayed as 1.0E7. This not only looks confusing, but it also does not provide a satisfactory user experience.

The challenge here is that you want to avoid this scientific notation and display the complete number without formatting issues, all while sticking to JSF solutions rather than altering backend Java code.

The Solution: Using h:outputText

You may have attempted to use the <f:convertNumber/> tag without success. This is because f:convertNumber only works on components that directly contain numerical values. However, there's a workaround that doesn't seem well documented but can effectively solve your issue.

Step-by-Step Implementation:

Change the Structure of Your OutputLabel:
You can improve formatting by avoiding the value attribute in p:outputLabel, allowing you to use its body instead for more complex structures:

[[See Video to Reveal this Text or Code Snippet]]

Incorporate h:outputText for Formatting:
Insert the numerical value inside h:outputText, applying the appropriate formatting through f:convertNumber:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code:

<p:outputLabel>: This remains the main container for your display label but without the need for a single value string.

<h:outputText>: This tag allows the numeric part to be more interactively formatted and gives us the opportunity to apply number formatting.

<f:convertNumber pattern="# "/>: This is key to avoiding scientific notation. The pattern "# " ensures that JSF displays the number as an integer without decimal places.

Conclusion

By restructuring how we output labels and incorporating h:outputText for the numerical component, we can solve the issue of unwanted scientific notation in JSF. This approach not only enhances visual clarity but also aligns well with best practices in JSF development.

With these steps, you can ensure that your numeric outputs stay user-friendly and appropriately formatted, providing a polished interface for your JSF applications.

Feel free to experiment with this solution on your upcoming JSF projects and enhance the user experience!