Java – thymeleaf email template and conversionservice

I have a spring MVC application. I try to render a date localdate as a string. It works for normal views, but it doesn't work for e-mail and throws the following error:

Code:

import org.thymeleaf.context.Context;
import org.thymeleaf.spring4.SpringTemplateEngine;

@Service
public class EmailService {

    @Autowired
    private SpringTemplateEngine templateEngine;

    public String prepareTemplate() {
        // ...
        Context context = new Context();
        this.templateEngine.process(template,context);
    }
}

Solution

I debugged and found that if we use the newly constructed context, it will create another conversionservice instance instead of using the defaultformattingconversionservice bean

In the spelvariableexpressionevaluator of thymeleaf spring, we see the following code

final Map<String,Object> contextVariables =
                computeExpressionObjects(configuration,processingContext);

        EvaluationContext baseEvaluationContext =
                (EvaluationContext) processingContext.getContext().getVariables().
                        get(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME);

        if (baseEvaluationContext == null) {
            // Using a standard one as base: we are losing bean resolution and conversion service!!
            baseEvaluationContext = new StandardEvaluationContext();
        }

To solve this problem, we must ensure that our context contains a million dollar evaluation context initialized with the correct transformation service

import org.thymeleaf.context.Context;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.springframework.core.convert.ConversionService;
import org.springframework.context.ApplicationContext;

@Service
public class EmailService {

    @Autowired
    private SpringTemplateEngine templateEngine;

    // Inject this
    @Autowired
    private ApplicationContext applicationContext;

    // Inject this
    @Autowired
    private ConversionService mvcConversionService;

    public String prepareTemplate() {
        // ...
        Context context = new Context();
        // Add the below two lines
        final ThymeleafEvaluationContext evaluationContext = new ThymeleafEvaluationContext(applicationContext,mvcConversionService);
        context.setVariable(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME,evaluationContext);
        this.templateEngine.process(template,context);
    }
}

The problem is solved