code: private static TemplateEngine doCreate(TemplateConfig config) {
  		try {
  			return new BeetlEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		try {
  			return new FreemarkerEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		try {
  			return new VelocityEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		try {
  			return new RythmEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		try {
  			return new EnjoyEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		try {
  			return new ThymeleafEngine(config);
  		} catch (NoClassDefFoundError e) {
  			// ignore
  		}
  		throw new TemplateException("No template found ! Please add one of template jar to your project !");
  	}
docs: 根据用户引入的模板引擎jar，自动创建对应的模板引擎对象
  
  @param config 模板配置，包括编码、模板文件path等信息
  @return {@link Engine}