Replace Variables with issue as empty String

[rider87]

Hi,

I have a HTML Text, which will have some Thymeleaf variables.
If I have some unknown variables etc. I will get always an error message an the String will not replace with variables anymore.
I would like to replace the values for which I got an error just with an empty String ("").
How can I do this?

Here a simple test: customer. (with dot) is an issue for Thymeleaf, therefore I will get an error.

`public static void main(String[] args) {

	StringTemplateResolver templateResolver = new StringTemplateResolver();
	templateResolver.setTemplateMode(TemplateMode.HTML);

	// Erstelle eine Template-Engine
	TemplateEngine templateEngine = new TemplateEngine();
	templateEngine.setTemplateResolver(templateResolver);

	String templateString = "<p>Hello, {{customer.name}} !</p>";

	Customer customer = new Customer();
	customer.setName("Meier");

	Context context = new Context();
	context.setVariable("customer.", customer);

	templateString = replaceCustomVariableSyntax(templateString);

	// Prozessiere das Template mit den Variablen
	StringWriter stringWriter = new StringWriter();

	try {
		templateEngine.process(templateString, context, stringWriter);
	} catch (Exception e) {
		// Catch any exceptions and return an empty string
	}

	System.out.println(stringWriter.toString());
}

`

Any ideas?

[duoduobingbing]

I do not know if I understand your problem correctly but as this setup is using OGNL please make sure to include the adequate dependency of ognl:ognl (for Thymeleaf 3.1.2 its OGNL 3.3.4)

It is unclear what your replaceCustomVariableSyntax(templateString); method does but I guess it replaces the {{customer.name}} with something OGNL can handle like [[${customer.name}]] so that the final template string looks something like <p>Hello, [[${customer.name}]] !</p>

When you add customer. as a variable, there is no customer, thus the lookup of customer.name in your template fails with a null pointer exception. If you want an empty string, just use safe navigation:

<p>Hello, [[${customer} ? ${customer.name}]] !</p>

This will succeed even when customer is not set in the context.