Process HTML file using Thymeleaf in Web based Scopes of Spring and store the processed template as String

Question

I am trying to render an HTML file using thymeleaf and keep the resultant HTML content in a String variable in web-based scopes of Spring so that i can use it l

Answer 1

If TemplateEngine is autowired inside a singleton bean, then the below mentioned code works perfect.

@Controller
public class jataController {

    @Autowired
    private TemplateEngine templateEngine;

    @GetMapping(value = "/manual-thym")
    @ResponseBody
    public void justSample() {
        Context context = new Context();
        String filename = "templates/view/generated-ticket.html";
        String html = renderHtml(filename, context);
        System.out.println("template\n" + html);
    }

    private String renderHtml(String filename, Context context) {

        ClassLoaderTemplateResolver templateResolver = new ClassLoaderTemplateResolver();
        templateResolver.setSuffix(".html");
        templateResolver.setTemplateMode(TemplateMode.HTML);
        templateResolver.setCacheable(false);
        templateResolver.setOrder(1);
        templateResolver.setCharacterEncoding("UTF-8");

        templateEngine.setTemplateResolver(templateResolver);

        String html = templateEngine.process(filename, context);

        return html;
    }
}

but if TemplateEngine is autowired on a request scope bean type, it gives exception and thymeleaf will create a memory leak. So finally with lots of hit and tries, i got a working solution and thanks to @Paizo. It might contain some bad practice but this is how it worked:

@Controller
@Configuration
@EnableWebMvc
@ApplicationScope
public class MyThymeleafConfig {

    @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);
    }


    /*

    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;
    }
}

and to serve the static resources we need to define another bean, which is as follows:

@Configuration
@EnableWebMvc
public class StaticResourceConfig implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry
                .addResourceHandler("/**")
                .addResourceLocations("/static/", "classpath:static/");
    }
}

This solution cannot be found on any forum. However i would ask as well as request any Spring developer to provide a better implementation for the above code.