My question is:
I'm doing a website that requires to update some div contents (img,h1,p) based on a database data (I'm doing some queries).
So which one is better for this, JSP or Servlets?
you should use both of them. the concept behind my answer is separation of concerns. ui should be separated from logical part or business processing part. this is why MVC design pattern come in existence.
The batter design include
JSP as View
Servlet as controller
POJO as service to access models
use servlet to dispatch the request to jsp ,when processing is done .use pojo for business logic and access them in servlet. after all is done set sheared variables as request/session attributes so that you can access them in view.
Technically, JSP(s) are compiled into Servlet(s) so neither is "better" then the other. I would suggest you put the business logic into Controller Servlet(s) and your presentation in JSP(s). I think you'll find there is a reason both continue to exist in the Java world.
It must follow MVC pattern.
From JSP call a method in Controller which will then call DAO layer and get the data.
Based on the data you receive, you can process it in the JSP using scriptlet or jstl tags.
It's better to create a reusable JSTL tag if you are planning to use it in multiple pages.
So JSP is better in that use case
Related
I have always worked with Web APIs, so I don't know how to handle this very basic problem in .NET Core MVC (I am only familiar with MVC conceptually). My problem:
I need a user to select an option from a dropdown on the front end and then show some data based on the option (after fetching it).
If I were writing an SPA consuming an API, I would simply make a call to the backend to get the data and then generate the html to display it on the front end.
How is this handled in MVC? Isn't the convention to return entirely new views? How are things like these handled?
I just need a pointer in the right direction conceptually - I can figure out the code.
Edit: Should I just pretend it's an SPA despite it being a view and create an API endpoint in the same app that provides the view and consume it from the cshtml?
It works exactly the same way. You make an AJAX call to fetch some data. You can either return the data directly, and utilize JS to render the HTML or return HTML directly. Either way, you use the AJAX callback to replace the appropriate content on the page.
Even in older ASP.NET MVC projects it worked this way, though you basically had to decide whether you were going to use an MVC controller or a Web Api controller to do the work. Either would work, but there were advantages/disadvantages to each approach. MVC/Web Api could always coexist in the same project.
In ASP.NET Core, the difference is purely semantic. There's really no such thing as MVC and Web Api anymore - just ASP.NET Core. A controller is a controller is a controller, so just add an endpoint and go to town.
I am working on play framework with SCALA as backend.
Json data is given to the front end from the controller.
I want to add HTML as value of some fields of json.
This HTML will be kept as a template and data will be added in this template at run time.
I think i should put unique names in the HTML template and then these names will be replaced by the data which i want to add at run time. Ultimately, this HTML will be added in the json response.
Is my approach right? If not, what is the best approach to add data in an HTML template,add this template in json response and send this combined response to the front-end for further use?
Is it a good practice to use string replacement to add data in an HTML template?
I think as long as you use Play, you can put your HTML templates into app/views package. Let's say you call your template mytemplate.scala.html
You can parameterize this view as any Play view.
In the place in your code where you generate your JSON response you can then call mytemplate(parameters) to get html generated, Play will do all the work here for you. Then using play.api.libs.json.JSON object's methods and related facilities you can convert this html to JSON.
So in your controller's code you will have something like Ok(JSON.toJson(mytemplate(parameters)))
This is of course a sketch, so you will need to elaborate and try.
I'm trying to set up a basic component that is rendered on the server and the client. The component is populated with data from a JSON API. I've got this working on the client-side by loading my data in componentDidMount and calling this.setState when it has loaded.
The problem I have is that the data isn't loaded on the server. How do I get the initial data into the server-rendered version of my component?
https://github.com/rackt/react-router/blob/latest/docs/guides/advanced/ServerRendering.md is very vague about this:
For data loading, you can use the renderProps argument to build
whatever convention you want--like adding static load methods to your
route components, or putting data loading functions on the
routes--it's up to you.
Do you have an example anywhere of how to do this? It seems like a very basic thing for a universal application to want to do!
Yup - we have https://github.com/rackt/async-props that provides a library for dealing with async data between server and client, and provides an example for doing so. If you're using a Flux framework, you'll want to make appropriate adjustments, but the basic approach will be quite similar.
From what I've read, one would generally use a global variable so that all controllers have access to some data.
Is there an "best-practice" way of accessing global data in the view templates? The use case would be for storing semi-static data like the website's brandname or location address. If in the future that data changes (ie, rebranding), it would be trivial to update the view to reflect those changes.
This thread suggests that using $rootScope is bad, and a better way would be to use a Service. However, in my case this gets messy because I have to mentally remember to include the service and create a scope var in each controller that has a template that will reference the static data.
I've seen suggestions of storing this data in a database, and then querying for it when needed. But that advice tends to be for server-side frameworks, and I would rather not do a GET query to the server just to grab static data in Angular.
I could leave it hardcoded as I have it now, and just run a grep to search and update whatever templates.
Is there a way to assign static data to variables once, and then have it be accessed in the templates without going through hoops? And all the while following Angular best practices? Or perhaps hardcoding the the easiest/cleanest approach?
Service Factory behave like singleton, when injected in different module you actually access the same data so it works perfectly for communication between controller.
Each component dependent on a service gets a reference to the single instance generated by the service factory.
If you want access those data in your template, just include the object in your scope, display. This will automatically implement two-way binding and is a good practice for MVC pattern.
To know the difference between Service and Factory : angular.service vs angular.factory
But try to avoid as much as possible to use global variable :D
BUT
This apply in a perfect world with perfect developer ... I love using a global variable like SETTINGS (uppercase to make it sounds constant) and which include some data required before angular initialization for exemple.
Would work well for such data like title and stuff like you have. However, you still need to add it manually in your scope (which for a title would be ... once ? Yeah seems ok)
I need to know how to implement the external paging and sorting method of displaytag in struts2.
In the reference documentation, there is only jsp page information.
Further they provide that a class should implements the PaginatedList Interface for making the external paging and sorting.
Using the object of the PaginatedList implemented class, we can do the external Paging.
I tried the method that has been used in the following link Answer provided in the DispalyTag Pagination Problem
But the problem I am facing now is, after implementing the abstract methods of the PaginatedList ,
How to use the object of the class to perform the external paging function?
How to set the values for the methods?
And how to retrieve the index and page numbers in action class?
The object is not retrieved in the jsp page.showing error like size attribute is not defined.
I searched the internet, but I could not find any clear resources or examples.
Please help me to solve the problem.
I will be thankful if any good examples are provided and also suggestions.