Annotated a class with @Configuration and @Controller. Need help in refactoring

Question

Below is my class in which i had to use both @Configuration and @Controller as there should be only one instance of Thymeleaf in the e

Answer 1

To refactor them, it's easy and straight forward to separate @Bean methods to a separate @Configuration class:

@Configuration
// @Controller  is redundant as we have @Configuration
// @EnableWebMvc is also redundant since you already annotate it in other class
// @ApplicationScope is also redundant since you do not need to create bean of MyThymeleafConfig anymore
public class MyThymeleafConfig {
    /*

    configuration for thymeleaf and template processing

    */

    @Bean
    public SpringTemplateEngine templateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(thymeleafTemplateResolver());
        return templateEngine;
    }

    @Bean
    public SpringResourceTemplateResolver thymeleafTemplateResolver() {
        SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
        templateResolver.setPrefix("classpath:");
        templateResolver.setSuffix(".html");
        templateResolver.setCacheable(false);
        templateResolver.setTemplateMode(TemplateMode.HTML);
        return templateResolver;
    }

    @Bean
    public ThymeleafViewResolver thymeleafViewResolver() {
        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setTemplateEngine(templateEngine());
        return viewResolver;
    }
}

@Configuration class return the same bean instance, regardless how many times you call the bean methods.

Now in your controller:

@Controller
public class MyThymeleafConfig {

    @Autowired
    private SpringTemplateEngine templateEngine;

    @GetMapping("/view-template")
    @ResponseBody
    public void viewTemplates() {

        Context context = new Context();
        context.setVariable("mydata", "this is it");

        String html = templateEngine.process("templates/view-to-process.html", context);
        System.out.println(html);
    }
}

But honestly, I don't know why you have to manually interact with TemplateEngine / SpringTemplateEngine, since Spring-thymeleaf will automatically process the template with given variable for you. (Like @sedooe example)