卡住，不知道为什么Spring表单是无法成功提交[给绑定的问题]时预填充在GET Request调用loadForm ，但在方法填充时正常工作setupFormObject与@ModelAttribute注解标签。 我可以提供在github上测试出一个简单的例子，如果问:)
下面的示例
@ModelAttribute("showForm")
public ShowForm setupFormObject() {
//Instantiate showForm with data
return showForm;
}
@RequestMapping(method = RequestMethod.GET)
public ModelAndView loadForm(@RequestParam("id") String id, HttpSession session) {
ModelAndView modelAndView = new ModelAndView(nextPage);
//Instantiate showForm with data
//modelAndView.addObject("showForm", showForm);
return modelAndView;
}
@RequestMapping(method = RequestMethod.POST)
public String post(@ModelAttribute("showForm") ShowForm showForm, BindingResult result, final RedirectAttributes redirectAttrs) {
//I see changed data here in showForm when populated using @setupFormObject
//See an exception in JSP with binding error if populated in loadForm
return "";
}
堆栈跟踪的要求。 这个例外是从github上的例子。
`HTTP Status 500 - Request processing failed; nested exception is org.springframework.beans.InvalidPropertyException: Invalid property 'users[0]' of bean class [com.example.UserForm]: Illegal attempt to get property 'users' threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property 'users' of bean class [com.example.UserForm]: Could not instantiate property type [com.example.UserEntity] to auto-grow nested property path: java.lang.InstantiationException: com.example.UserEntity`
`type Exception report`
`message Request processing failed; nested exception is org.springframework.beans.InvalidPropertyException: Invalid property 'users[0]' of bean class [com.example.UserForm]: Illegal attempt to get property 'users' threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property 'users' of bean class [com.example.UserForm]: Could not instantiate property type [com.example.UserEntity] to auto-grow nested property path: java.lang.InstantiationException: com.example.UserEntity`
`description The server encountered an internal error that prevented it from fulfilling this request.`
`exception`
`org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.beans.InvalidPropertyException: Invalid property 'users[0]' of bean class [com.example.UserForm]: Illegal attempt to get property 'users' threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property 'users' of bean class [com.example.UserForm]: Could not instantiate property type [com.example.UserEntity] to auto-grow nested property path: java.lang.InstantiationException: com.example.UserEntity`
`org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:927)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:822)
javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:796)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)`
`root cause`
`org.springframework.beans.InvalidPropertyException: Invalid property 'users[0]' of bean class [com.example.UserForm]: Illegal attempt to get property 'users' threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property 'users' of bean class [com.example.UserForm]: Could not instantiate property type [com.example.UserEntity] to auto-grow nested property path: java.lang.InstantiationException: com.example.UserEntity
org.springframework.beans.BeanWrapperImpl.getPropertyValue(BeanWrapperImpl.java:829)
org.springframework.beans.BeanWrapperImpl.getNestedBeanWrapper(BeanWrapperImpl.java:556)
org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:533)
org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:894)
org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:75)
org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:699)
org.springframework.validation.DataBinder.doBind(DataBinder.java:595)
org.springframework.web.bind.WebDataBinder.doBind(WebDataBinder.java:191)
org.springframework.web.bind.ServletRequestDataBinder.bind(ServletRequestDataBinder.java:112)
org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.bindRequestParameters(ServletModelAttributeMethodProcessor.java:153)
org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:106)
org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:77)
org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:162)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:123)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:746)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:687)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:915)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:822)
javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:796)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
`
你的帮助是高度赞赏
谢谢
