I'm migrating a Play! 1.2 web application and moving to Spring Boot + Spring MVC. Some views contain URLs to other endpoints. For example, I display the book title on the page and next to it I want to add the URL to go the book's details page (e.g. localhost/books/{id}).
In Play! 1.2 the controllers are static, and there is also a Router which can create the full URL for a method belonging to another controller (Router.getFullUrl("BookController.bookDetails", args)), but how do I achieve this with Spring MVC?
Best regards,
Cristian.
If you are trying to get the app/deployed name automatically in .jsp files to make the urls, then please make use of context path. An example below :
<c:set var="context" value="${pageContext.request.contextPath}" />
<script src="${context}/themes/js/jquery.js"></script>
From your requirement "admin.myapp.com","admin-test.myapp.com" are server names right? Something like http://admin.myapp.com/book/{bookId},http://admin-test.myapp.com/book/{bookId}. In Spring app, relative path in jsp can be accessed using pageContext.request.contextPath
I also found the UriComponentsBuilder and ServletUriComponentsBuilder. They are similar to the Play! Framework router and provide methods for building URI's, handling parameters and the query etc. We chose to annotate the controllers' methods using constants and then use the same constants with the UriComponentsBuilder to build back the path and create the request query for GET requests.
Related
I'm wondering is it possible to have path variable in server.servlet-path with DispatcherServlet? I know of course it possible in controller, but I'd like to have it in one place instead of updating 70 endpoints.
Like:
server.servlet-path=/{client-name}/api/v4
And for example that client-name will be available in request attributes, headers, etc.
Or I need to implement my own dispatcher which will do that logic?
Since REST based controller methods only return objects ( not views ) to the client based on the request, how can I show view to my user ? Or maybe better question what is a good way to combine spring-mvc web app with REST, so my user always get the answer, not in just ( for example ) JSON format, but also with the view ?
So far as I understood, REST based controller would be perfectly fitting to the mobile app ( for example twitter ), where views are handled inside the app and the only thing server has to worry about is to pass the right object to the right request. But what about the web app ?
I might be wrong in several things ( correct me if I am ), since I am trying to understand REST and I am still learning.
To simplify things - you basically have two options:
1) Build Spring MVC application.
2) Build REST backend application.
In case of first option - within your application you will have both backend and frontend (MVC part).
In case of second option you build only backend application and expose it through REST API. In most cases, you will need to build another application - REST client for your application. This is more flexible application because it gives you opportunity to access your backend application from various clients - for example, you can have Android, IOS applications, you can have web application implemented using Angular etc...
Please note, that thins are not so simple, you can within one application have both REST backend and REST client etc... This is just very very simplified in order that you get some general picture. Hope this clarified a little things.
There is some additional clarification related to REST and views worth learning. From your question, I can see that you mean "view" in a sense of UI(user interface) and typical MVC usage. But "view" can mean different things in a different contexts.
So:
JSON can be considered as a view for data
JSON is a representation of the resource, just like HTML is
JSON doesn't have style (unless you are not using a browser
extension, which most the users are not using)
The browser is recognizing HTML as a markup language and applying a
style to it
Both are media types
Both JSON and HTML are data formats
Both can be transferred over the wire
This method returns a view
#RequestMapping("/home")
String home(Model model) {
return "home"; // resources\templates\home.html
}
This method Returns String
#RequestMapping(value = "/home")
#ResponseBody
public String home() {
return "Success";
}
If you annotate a method with #ResponseBody, Spring will use a json mapper to generate the response. Instead of annotating every method with #ResponseBody you can annotate your class with #RestController.
If you want to return a view, you need to annotate the class with #Controller instead of #RestController and configure a viewresolver. Bij default spring will use thymeleaf as a viewresolver if you have spring-web as a dependency on the classpath. The return type of the method is a String that references the template to be rendered. The templates are stored in src/main/resources/templates.
You can find a guide on the spring website: https://spring.io/guides/gs/serving-web-content/
I'm using spring-boot-starter-data-rest and spring-boot-starter-web.
I've made a simple project using a CrudRepository, letting spring boot generate the rest request mappings.
Now, I want to add a client -- making the rest calls -- live under ./.
Hence, I'm trying to prefix the paths for the rest calls (and only those!) with /api.
I've tried the answers from :
How to specify prefix for all controllers in Spring Boot?
using settings in the application.properties file
server.contextPath=/api/*
spring.data.rest.basePath=/api/*.
But still the static content (e.g. index.html, *.js, *.css) is not fetched using ./. There urls are also prefixed by "/api/".
The rest calls are properly served under /api/foos.
Is there a way to tell spring not to treat urls that lead to sources located in src/main/resources/public as 'rest-controllers'?
Update
Setting the property
spring.data.rest.basePath=/api/*
works perfectly. (I still had a programmatic bean configuration in my sandbox overriding this setting).
Spring controllers are made for serving both HTML and JSON/XML. The first one is done via Spring MVC Views and some template engine like Thymeleaf, the latter is handled entirely by Spring and #RestController.
There's no way to have a context path for only the controllers that returns JSON or XML data, and not for the other controllers as well, this also goes for static content. What you typically do is have some static variable containing the prefix you want for your APIs, and the use that in the controller's #RequestMapping. i.e.
#RestController
#RequestMapping(MyConstants.API_LATEST + "/bookings")
public class MyBookingsController {
...
}
You probably want to approach the prefix problem with something along these lines anyway. It is common to have to support older API versions when you have breaking changes, at least for some time.
I want to use Spring MVC 3.0 to build interfaces for AJAX transactions. I want the results to be returned as JSON, but I don't necessarily want the web pages to be built with JSP. I only want requests to the controllers to be intercepted/routed through the DispatcherServlet and the rest of the project to continue to function like a regular Java webapp without Spring integration.
My thought was to define the servlet-mapping url pattern in web.xml as being something like "/controller/*", then have the class level #RequestMapping in my controller to be something like #RequestMapping("/controller/colors"), and finally at the method level, have #RequestMapping(value = "/controller/colors/{name}", method = RequestMethod.GET).
Only problem is, I'm not sure if I need to keep adding "/controller" in all of the RequestMappings and no matter what combo I try, I keep getting 404 requested resource not available errors.
The ultimate goal here is for me to be able to type in a web browser "http://localhost:8080/myproject/controller/colors/red" and get back the RGB value as a JSON string.
You are not correct about needing to add the entire path everywhere, the paths are cumulative-
If you have a servlet mapping of /controller/* for the Spring's DispatcherServlet, then any call to /controller/* will be handled now by the DispatcherServlet, you just have to take care of rest of the path info in your #RequestMapping, so your controller can be
#Controller
#RequestMapping("/colors")
public class MyController{
#RequestMapping("/{name}
public String myMappedMethod(#PathVariable("name") String name, ..){
}
}
So now, this method will be handled by the call to /controller/colors/blue etc.
I don't necessarily want the web pages to be built with JSP
Spring MVC offers many view template integration options, from passthrough to raw html to rich templating engines like Velocity and Freemarker. Perhaps one of those options will fit what you're looking for.
Hello i am developing a web app...i am using MVC architecture in my design.
i have one form add_Flat.jsp in which admin enter the flat details and it will be stored in database (MS-Access) no other jsp page would be open on submit button.just a message displayed on add_Flat.jsp.
How can i achieve this by using MVC pattern ? do i have to write different servlet for every jsp page ? and model class for database connectivity ?
How can i achieve this by using MVC pattern ?
Let the form submit to a servlet which sets the message in the request scope and forwards back to the JSP.
do i have to write different servlet for every jsp page ?
Not necessarily. You can write a single servlet which acts as a front controller, or just use an existing MVC framework like JSF, Spring MVC, etc.
and model class for database connectivity ?
A model class should not be aware about any DB connectivity. A model class should be a simple Javabean class.
See also:
Our servlets wiki page - Contains Hello World examples and links to in-depth answers on servlet related questions here.