在js中判断request中的list是否为空: if(!oldServiceType.equals(serviceType)) { Integer themeGrade = productvo.getThemeGrade(); List<TThemeVO> listTheme = this.getTthemeService().findListBySTypeAndTGrade(serviceType, themeGrade.longValue()); put("listTheme", listTheme); } 在jsp的js中: <S...