I have a small doubt with SpringMVC's command object. So the problem is, I have couple of forms which I am going to use in multiple pages (Around 17). I decided to make these two forms as JSP's and include them in the parent JSP's. The problem I am facing is that the textfields and dropdown's aren't populating with the data which is passed on from the server using Command object.
Lets call the Parent JSP as parent.jsp and than two included JPS's(which have the forms) as child1.jsp and child2.jsp. The controller for parent.jsp sets a ModelAttribute with name previousSales and returns the view as abc/parent where abc is the folder. (WEB-INF/jsp/abc/parent). My question is how do I make the model attribute available to the included JSP's?
The Command object should be part of your handler method calls, as follows:
#RequestMapping("/somepath/foo/do")
public String someHandlerMethod(
#ModelAttribute("commandObject") CommandObject commandObject,
Model model,
BindingResult result) {
...processing...
return("some.jsp");
}
On your JSP, use the Spring Forms TLD for the form fields, and the Command object will be bound to the form fields.
#RequestMapping("/somepath/foo/do")
public String someHandlerMethod(
#ModelAttribute("commandObject") CommandObject commandObject,
Model model,
BindingResult result) {
...processing...
return("some.jsp");
}
Related
I have a simple form that edits my profile on the web. 'Person' bean, that describes user, contains many internal fields that cannot be changed by the form. Therefore I have just a subset of fields available for editing on the form. So far so good. Now what if some advanced user opens developer tools in Chrome browser and adds some other fields on the form or rename some existing fields ... so when submitted those fields will be bound back to the 'Person' bean and stored into database. Such way the user can spoof my form easily and chnage values for not allowed fields. Is there a way how to define (server side) which fields (bean properties) can be bound during the form submit?
Here is how the controller method signature looks like to get an idea:
#RequestMapping(path = "/profile/edit", method = RequestMethod.POST)
public String editProfile(#ModelAttribute("profile") Person doc, BindingResult result, Model m){
... saving doc to database ...
}
I'm using SpringBoot 1.3.5 with Thymeleaf ...
Turned out that solution is quite simple. I just added #InitBinder annotated method to controller and used WebDataBinder provided object to specify list of fields allowed. To do this I can use binder.setAllowedFields(...) method. Field names support "xxx*", "*xxx" and "xxx" patterns so its easy to specify set of fields when named properly in the bean. Now when post request variables are bound to my bean, these allowed fields are preserved and the others are rejected and not bound.
Code example:
#InitBinder // or #InitBinder("profile") with ModelAttribute name information
public void initBinder(WebDataBinder binder) {
binder.setAllowedFields("settings*");
}
See DataBinder docs for detailed info.
I have been reading this forum for quite awhile and find it VERY useful, thank you to the contributors. I have a question that has plagded me for several weeks. And here it goes.
#RequestMapping(value="updateNote.htm",method=RequestMethod.POST)
public String updateNote(#ModelAttribute("note")NoteBean nb, BindingResult res,Model model){
daoobj.updateNote(nb.getName(),nb.getPath(), nb.getNote());
model.addAttribute("note",daoobj.getByName(nb.getName()));
return("success");
}
#RequestMapping(value="updateNote.htm",method=RequestMethod.GET)
public String updateNote(#ModelAttribute("note")NoteBean nb,Model model){
populateNoteBean();
model.addAttribute("note",daoobj.getByName(nb.getName()));
return("editNote");
}
#ModelAttribute("WHAT")
public NoteBean populateNoteBean() {
NoteBean nnb = new NoteBean();
return nnb;
}
With the method populateNoteBean() the model attribute is "WHAT". But, the name that I use is "note". So when I run the code, the NoteBean is correctly saved to the data base. My question is HOW?? It seems that the name "WHAT" should be "note" or that the model attribute is saving it as no name.
Thank for your time.
With your current code you will have two instances of your notebean in the model!
First spring invokes all modelattribute annotated methods in your controller and places the results in the model. Second it evaluates the ones from your requestmapping method.
The point of a modelattribute annotated method is that you can choose how to create your bean. Load it for example from a database.
We use this approach like that:
modelattr method (name="note")
Loads beans from db
requestmapping method with modelattr param (name="note")
Merges the note bean created by the first method with the request paramters from a submit for example and you habe directly access to the modifed one.
One nice effect:
We do not want to put hidden input fields for all attributes in a form just to be able to merge the entity with the entitymanager. This way you can have a form with only one attribute (plus one for the id to be able to fetch the entity)
Or another one:
If your note bean is an abstract class spring has no possibility to instanciate the bean because it does not know what to instanciate. You can for example add a requestparam parameter in the modelattr annotated method and decide what to do yourself.
This is very well described in the documentation. Either the reference or in the api of either controller, reqestmapping or modelattribute i believe.
I have seen many examples on how simpleFormcontroller works.
But still I have some confusion.
I want to know when formBackingObject(), referenceData(), onSubmit() methods invoked?
I dont know exact working flow of these methods?
Can anyone explain me?
Workflow is as follows and it is controlled by AbstractFormController class-
The controller receives a request for a new form (typically a GET).
Call to formBackingObject() which by default, returns an instance of the commandClass that has been configured (see the properties the superclass exposes), but can also be overridden to e.g. retrieve an object from the database (that needs to be modified using the form).
Call to initBinder() which allows you to register custom editors for certain fields (often properties of non-primitive or non-String types) of the command class. This will render appropriate Strings for those property values, e.g. locale-specific date strings.
Only if bindOnNewForm is set to true, then ServletRequestDataBinder gets applied to populate the new form object with initial request parameters and the onBindOnNewForm(HttpServletRequest, Object, BindException) callback method is called. Note: any defined Validators are not applied at this point, to allow partial binding. However be aware that any Binder customizations applied via initBinder() (such as DataBinder.setRequiredFields(String[]) will still apply. As such, if using bindOnNewForm=true and initBinder() customizations are used to validate fields instead of using Validators, in the case that only some fields will be populated for the new form, there will potentially be some bind errors for missing fields in the errors object. Any view (JSP, etc.) that displays binder errors needs to be intelligent and for this case take into account whether it is displaying the initial form view or subsequent post results, skipping error display for the former.
Call to showForm() to return a View that should be rendered (typically the view that renders the form). This method has to be implemented in subclasses.
The showForm() implementation will call referenceData(), which you can implement to provide any relevant reference data you might need when editing a form (e.g. a List of Locale objects you're going to let the user select one from).
Model gets exposed and view gets rendered, to let the user fill in the form.
The controller receives a form submission (typically a POST). To use a different way of detecting a form submission, override the isFormSubmission method.
If sessionForm is not set, formBackingObject() is called to retrieve a form object. Otherwise, the controller tries to find the command object which is already bound in the session. If it cannot find the object, it does a call to handleInvalidSubmit which - by default - tries to create a new form object and resubmit the form.
The ServletRequestDataBinder gets applied to populate the form object with current request parameters.
Call to onBind(HttpServletRequest, Object, Errors) which allows you to do custom processing after binding but before validation (e.g. to manually bind request parameters to bean properties, to be seen by the Validator).
If validateOnBinding is set, a registered Validator will be invoked. The Validator will check the form object properties, and register corresponding errors via the given Errors object.
Call to onBindAndValidate() which allows you to do custom processing after binding and validation (e.g. to manually bind request parameters, and to validate them outside a Validator).
Call processFormSubmission() to process the submission, with or without binding errors. This method has to be implemented in subclasses.
Source
For more details and diagrammatic representation to understand the flow you can refer to below link -
SimpleFormController is deprecated since Spring 3.0
In Spring 3.0 use one controller with two methods for the creation process (and a third one for the show page). It typical looks like that:
/**
* Shows a form for car creation.
*/
#RequestMapping(params = "form", method = RequestMethod.GET)
public ModelAndView createForm() {
ModelMap uiModel = new ModelMap();
uiModel.addAttribute("carCreateFormBackingObject", new CarCreateFormBackingObject()); //formBackingObject - often called command object
uiModel.addAttribute("manufactureres", this.manufactureresDao.readAll()); //referenceData
return new ModelAndView("car/create", uiModel);
}
/**
* Creates the car and redirects to its detail page.
*
*/
#RequestMapping(method = RequestMethod.POST)
public ModelAndView create(final #Valid CarCreateFormBackingObject carCreateFormBackingObject,
final BindingResult bindingResult) {
if (bindingResult.hasErrors()) {
ModelMap uiModel = new ModelMap();
uiModel.addAttribute("carCreateFormBackingObject", carCreateFormBackingObject);
uiModel.addAttribute("manufactureres", this.manufactureresDao.readAll()); //referenceData
return new ModelAndView("car/create", uiModel);
}
Car car = this.carService.create(carCreateFormBackingObject.name, ...);
return new ModelAndView(new RedirectView("/cars/" + car.getId(), true)); //redirect to show page
}
still i want to know formBackingObject(),refernceData() method get invoked automatically by whom and when?
Back to your question "still i want to know formBackingObject(),refernceData() method get invoked automatically by whom and when?"
All these methods get invoked by SimpleFormController (and its superclass AbstractFormController), the follow the Template-Method-Pattern. - SimpleFormController defines the process and your concrete subclass "plugsin" in some hooks of this process to gain the business value.
formBackingObject in invoked by AbstractFormController when the controller needs to handle a Submit (POST), or build the Command object for the initial "new" view.
referenceData is always invoked AbstractFormController when it need to build the model for the view.
formBackingObject() method, is used when you want to take some action before rendering page. i.e. like default value in HTML components.
refereceData() method, is used for add reference data in your form, i.e. populating dropdowns
OnSubmit() method, is called whe you submit form.
But, if you are using Spring 3.0
Follow following approach using annotation
#RequestMapping(value = "/index.htm", method = RequestMethod.GET)
public String showLogin() {
return "user/login";
}
This will same as formBackingObject. and in this method use modelMap() and add reference data.
Add methods same way with method = POST which will be same as OnSubmit()
rfe folling link
http://static.springsource.org/spring/docs/2.5.x/api/org/springframework/web/servlet/mvc/SimpleFormController.html
Read Workflow.. you can simply understand your doubts..
FormBackingObjectMethod()---> #RequestMapping(requestMethod.GET)
while first time form shown to the screen formBackingObject is the reason
initBinder()---> normally used for suppose you want date field should be for example (custom date example : dd**MM***yyyy) needed means use initBinder method
onSubmit() -->#RequestMapping(requestMethod.POST)
while submitting the form onSubmit() method get called
i hope this helps
I have a scenario where I have a list of filters that inherit from the same base class (BaseFilter). This are rendered in a few with different templates in a certain order based on what the user chooses. What is the best way to grab that data via javascript and submit it via an ajax request to a strongly typed List<IBaseFilter> in the ActionResult. Should I use a model binder and if so how with a list of IFilters?
public ActionResult Save(List<IFilter> filters)
{
}
public FirstFilter : BaseFilter {
// Has Two Properties
}
public SecondFilter : BaseFilter {
// Has One Property
}
Casting from child to parent means that you loose all child properties, and you only get parent properties. If you model bind filters to IFilter then only properties existing in IFilter would be available to you. I recommend that you create two action methods, and save filters consecutively, if possible, and use strongly-typed model binding in those actions. Another options might be to send data to the action method, but extract information manually from HTTP request, rather than letting ASP.NET MVC bind incoming parameters to your List<IFilter> parameter.
Basically Binders get what's in the FormCollection, and convert them to nice model objects for you. You probably can create a customized binder (IModelBinder implementation) to do all that for you. See this post to get an idea on how they work.
I'm a php programmer now doing a Java web project using Spring framework. I'm trying to organize my JSP files the way i would have organized my .tpl files in php.
So if it would have been php i would have done it like this:
index.tpl
includes one of layout.tpls (ajax.tpl, mobile.tpl, general.tpl, simplified.tpl . . .)
includes the header of the page
includes menus
includes the actual content of the page
includes the page footer
then from the php controller i would be able to do something like this:
setLayout('general');
showTopMenu(false);
setContent('mySexyPage');
beside that i would have organized my stuff so that my views (tpl files) will be organized in folderŅ each corresponding to a single controller. like this:
userManager
addUSer.tpl
editUser.tpl
editUserPermissions.tpl
articleManager
addArticle.tpl
editArticle.tpl
and in each controller somehow define from which folder to load my content template.
Now in Spring i have a controller with methods handling requests and each of the methods returning what the view should be. I can extend all my controllers from a single abstract class where i will create an instance of ModelAndView with all default values set, then request handling methods will add what they need to the instance their daddy already created and return it.
The problem with the above approach is that i'm not forcing the coder who's writing controllers to use the ModelAndView object i created, he way still return anything he wants from the handling method he wrote.
Is there some interface containing a method like ModelAndView getModelAndView() my daddy controller will implement so Spring will ignore whatever handler methods are returning?
Or is there some better way to do this ?
Content Template Issue
The Java world has a (more than one actually, but I'm sticking with the one I know) solution for this problem, it is called Tiles. check out section 16 of the Spring 3.0.5 Reference.
ModelAndView Issue
This is more interesting. First, you can use Model with out view and have your controllers just return the view name (i.e. return a String). I believe you want to create the initial Model somewhere. Then have each controller hander method accept an argument of type Model.
Here is what I tend to do (no claim that it is a best practice):
Have a Controller.get(Model model) method that sets the initial values.
#RequestMapping(method = RequestMethod.GET)
public String get(Model model)
{ ... set default stuff ... }
Every Handler method is a variation of this:
#RequestMapping(value = "/search", method = RequestMethod.POST)
public String search(Model model, ... other stuff as needed ...)
{ ... set stuff in model ... }