spring boot send email html template
@Bean
public FreeMarkerConfigurer freemarkerClassLoaderConfig() {
Configuration configuration = new Configuration(Configuration.VERSION_2_3_27);
TemplateLoader templateLoader = new ClassTemplateLoader(this.getClass(), "/mail-templates");
configuration.setTemplateLoader(templateLoader);
FreeMarkerConfigurer freeMarkerConfigurer = new FreeMarkerConfigurer();
freeMarkerConfigurer.setConfiguration(configuration);
return freeMarkerConfigurer;
}