问题见：https://stackoverflow.com/questions/53803497
为什么按照官网上的写法调用@Bean报错：EL1057E: No bean resolver registered in the context to resolve access to bean
有时候我们希望自己去通过thymeleaf进行解析文本，调用自定义的函数。比如
Context context = new Context(); context.setVariables(dataMap); templateEngine.process(templateName, context);
如果我们在模板里使用了 ${@beanName.method()}，此时会报错：
EL1057E: No bean resolver registered in the context to resolve access to bean
但是如果我们是通过模板进行MVC页面渲染就不会报错，其实原因就是因为此时的context里缺少了spring的Beans的信息，通过spring mvc渲染时，框架会加入这些信息。那么手动渲染时我们也添加Beans的信息就可以了。
Context context = new Context(); context.setVariables(dataMap); ThymeleafEvaluationContext tec = new ThymeleafEvaluationContext(applicationContext, null); dataMap.put(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME, tec); templateEngine.process(templateName, context);
此时在进行渲染就正常了。
如果想更接近 Spring MVC 解析逻辑的，参考如代码：
@RequestMapping(value = "/uploadApk", produces = "text/javascript")
@ResponseBody
public String fragUploadApk(@NonNull final HttpServletRequest request, @NonNull final HttpServletResponse response) {
final WebContext context = new WebContext(request, response, request.getServletContext(), request.getLocale());
# 此处使用 Spring MVC 默认的 FormattingConversionService.class 完成对数据的格式化（Springboot 2.7.11)
final FormattingConversionService conversionService = applicationContext.getBean(FormattingConversionService.class);
final ThymeleafEvaluationContext thymeleafEvaluationContext = new ThymeleafEvaluationContext(requireApplicationContext(), conversionService);
context.setVariable(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME, thymeleafEvaluationContext);
templateEngine.process(templateName, context);
}