code: private EvaluationContext createEvaluationContext(Object rootObject, Context beetlContext) {
  		StandardEvaluationContext context = new StandardEvaluationContext(rootObject);
  
  		// 允许使用#context访问Beetl上下文
  		context.setVariable("context", beetlContext);
  		// 允许使用#global访问Beetl上下文的全局变量
  		context.setVariable("global", beetlContext.globalVar);
  		// 注册WebRender定义的全局变量
  		context.setVariable("ctxPath", beetlContext.getGlobal("ctxPath"));
  		context.setVariable("servlet", beetlContext.getGlobal("servlet"));
  		context.setVariable("parameter", beetlContext.getGlobal("parameter"));
  		context.setVariable("request", beetlContext.getGlobal("request"));
  		context.setVariable("session", beetlContext.getGlobal("session"));
  		// 允许使用属性格式访问Map
  		context.addPropertyAccessor(new MapAccessor());
  		// 允许访问Spring容器Bean
  		context.setBeanResolver(new BeanFactoryResolver(applicationContext));
  
  		return context;
  	}
docs: 创建SpEL执行上下文
  
  @param rootObject
  SpEL表达式根对象
  @param context
  Beetl上下文对象
  @return SpEL表达式执行上下文