How to access spring boot properties from freemarker template

Question

My problematic is really simple :

In my spring-boot web application, I have some env-related properties that the front/client-side needs to know about (let's say, a CORS remote url to call that is env dependant).

I have correctly defined my application-{ENV}.properties files and all the per-env-props mecanism is working fine.

The question I can't seem to find answer to is : how do you allow your freemarker context to know about your properties file to be able to inject them (specifically in a spring-boot app). This is probably very easy but I cant find any example...

Thanks,

Answer 1

Gonna answer myself :

Easiest way in spring-boot 1.3 is to overrides the FreeMarkerConfiguration class :

/**
 * Overrides the default spring-boot configuration to allow adding shared variables to the freemarker context
 */
@Configuration
public class FreemarkerConfiguration extends FreeMarkerAutoConfiguration.FreeMarkerWebConfiguration {

    @Value("${myProp}")
    private String myProp;

    @Override
    public FreeMarkerConfigurer freeMarkerConfigurer() {
        FreeMarkerConfigurer configurer = super.freeMarkerConfigurer();

        Map<String, Object> sharedVariables = new HashMap<>();
        sharedVariables.put("myProp", myProp);
        configurer.setFreemarkerVariables(sharedVariables);

        return configurer;
    }
}

Answer 2

One option in spring boot 2:

@Configuration
public class CustomFreeMarkerConfig implements BeanPostProcessor {

  @Value("${myProp}")
  private String myProp;

  @Override
  public Object postProcessBeforeInitialization(Object bean, String beanName)
  throws BeansException {
      if (bean instanceof FreeMarkerConfigurer) {
          FreeMarkerConfigurer configurer = (FreeMarkerConfigurer) bean;
          Map<String, Object> sharedVariables = new HashMap<>();
          sharedVariables.put("myProp", myProp);
          configurer.setFreemarkerVariables(sharedVariables);
      }
      return bean;
  }
}

Spring Boot 2.x changed class structure so it's no longer possible to subclass and keep the auto configuration like was possible with Spring Boot 1.x.

Answer 3

import freemarker.template.Configuration;

@Component
public class FreemarkerConfiguration {

    @Autowired
    private Configuration freemarkerConfig;

    @Value("${myProp}")
    private String myProp;

    Map<String, Object> model = new HashMap();
    model.put("myProperty", myProp);
  

    // set loading location to src/main/resources
    freemarkerConfig.setClassForTemplateLoading(this.getClass(), "/");
    Template template = freemarkerConfig.getTemplate("template.ftl");
    String templateText = FreeMarkerTemplateUtils.
                                    processTemplateIntoString(template, model);

}   


     
  step 2, 
   get property in freemarker template code.
     <div>${myProperty}</td>