Question
What are the key functions available in the Velocity template engine for manipulating strings?
#foreach($word in ['Hello', 'World'])
$word.toUpperCase() // Outputs each word in uppercase.
#end
Answer
Velocity is a Java-based template engine that allows for dynamic content generation. String manipulation is one of its core features, using functions that operate on text to enhance functionality and improve templating performance.
#set($greeting = "Hello")
#set($name = "World")
${greeting}, ${name}! // Outputs: Hello, World!
Causes
- A lack of understanding of how string functions work can lead to inefficient template rendering.
- Neglecting to utilize caching features within Velocity can slow down performance, especially with complex string manipulations.
Solutions
- Leverage built-in string functions such as `toUpperCase()`, `substring()`, and `indexOf()` for quick text transformations.
- Consider using the `#set` directive to store intermediate results and re-use them across your template for performance optimization.
- Implement proper escape functions such as `escapeHtml()` to avoid security risks when displaying user-generated content.
Common Mistakes
Mistake: Not escaping strings correctly, leading to security vulnerabilities.
Solution: Always use escape functions like `escapeXml()` or `escapeHtml()` when rendering user inputs.
Mistake: Overlooking null values which can cause templates to fail.
Solution: Use conditional statements to check for null before processing strings, e.g., `#if($variable)`.
Helpers
- Velocity string functions
- Velocity template engine
- string manipulation in Velocity
