passing a Spring Exception to a Thymeleaf page - spring

Having added the error.html Thymeleaf template to replace the default error page on Spring how can I get access to the exception on that page?
So I have custom exception thrown on some controller. How to access that exception on the Thymeleaf page?
I want this to work globally, so any controller thrown exception should be accessible.

Case 1: For customized error pages with spring default error info
There are some predefined objects in Thymeleaf to show error information, e.g. ${error}, ${exception} and so on. These objects can be used in your customized error page.
This article will help you more. Custom Error Page with Thymeleaf
Case 2: For customized error pages with customized error info
There are #ControllerAdvice and #ExceptionHandler used to handle exceptions in controllers globally. A certain exception can be add to Modal's attribute and therefore accessed in thymeleaf templates. However, please be noted that the solution does not work in Webflux.
The blog shows details about the solution. Exception Handling in Spring MVC

Related

What is exactly server.error.path property?

In Spring Boot, what is the purpose of server.error.path property in application.properties file?
The documentation just says:
Path of the error controller
But I want a clear description of this property with an example.
server.error.path - used as part of url for error pages.
site.getBaseUrl() + "/error"
For example some error happen on server side and you decide redirect user to error page like this:
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/images/custom-error-page-aws-404-example.png
Code example of error controller you can find here:
https://www.logicbig.com/tutorials/spring-framework/spring-boot/implementing-error-controller.html
You can use this property in #RequestMapping("/error"). But instead of "/error" you can use "${server.error.path}"
UPDATE:
Also, Spring Boot BasicErrorController use server.error.path property
Property server.error.path in spring boot application used to define an error path while dealing with custom error handler. In Spring we create custom error handler using functional interface ErrorController, ths interface has a String type method getErrorPath which helps us to return the error page path(our error page as view).
But from Spring 2.3.0 this getErrorPath() method has been deprecated and replaced with server.error.path to manage the error path.
e.g. server.error.path=/error
For more detail about interface ErrorController, please refer Spring doc for ErrorController

Using Vaadin Error View instead of Spring Boot's Whitelabel error page

I'm using Spring Boot with Vaadin and. By using the #Autowired SpringNavigator, I have also set the error view:
navigator.setErrorView(ErrorView.class);
But when I type wrong URL like http://localhost:8080/asdf .
I always get the Spring Boot's Whitelabel error page. I know that I can set custom HTML page for the error like
/resources/public/error/404.html
but this is HTML way, I would like to use Vaadin with components,
the best solution would be the mentioned error view.

Custom page not found and other error webpages in Spring 3.0

I want to display a custom 404 page not found error page (among others). I'm using Spring 3.0 and don't know how to do this.. I know I can specify a jsp page in web.xml to handle 404 errors. But I want Spring's environment for my error pages. So I tried simply returning a ModelAndView that's basically an error page. But the problem there is once I do this:
response.sendError(HttpServletResponse.SC_NOT_FOUND);
Then the whole request just gets forwarded back to the container's default 404 page. How are we supposed to handle error pages in Spring 3.0?
In Servlet 2.4, response.sendError() and response.setStatus() are treated differently. The former is handled by container, but the latter gives option to provide the response yourself. That means, you have to use response.setStatus(HttpServletResponse.SC_NOT_FOUND). Please also see How do I return a 403 Forbidden in Spring MVC?

Server side Exception or error to be propagated to JSP in Spring

I am trying to show an custom error message on any occurrence of exception or error in my business layer. I am catching the exception in my controller and I would like to display it in my JSP.
This exception or error is not associated with any field in the screen, it's a pure server exception. I am also using an Annotated Controller. I am using Prototype for making AJAX requests to my controller.
In Spring you can register a HandlerExceptionResolver which will catch exceptions thrown by your Spring MVC controllers and forward them to the view layer for rendering. These are described in the Spring docs here. Start with the SimpleMappingExceptionResolver (see javadoc) which gives a simple mechanism for mapping exception types to views.
However, if the exception occurs outside if your Spring controller, for whatever reason, then you'll need a more generic fall-back solution, which involves configuring error pages in your web.xml file. This is not Spring-specific. See here for an example of how to do it.

How to configure spring HandlerExceptionResolver to handle NullPointerException thrown in jsp?

From a jsp is thrown a NullPointerException for example using <% null.toString(); %>
This exception is not handled by the HandlerExceptionResolver, but thrown to the web container(tomcat) and converted into a code 500 error.
How can I configure spring to get that error in my HandlerExceptionResolver ?
Details:
Spring can be configured to handle exceptions thrown inside Controllers, but not exceptions thrown by view.
Of course i can resolve the NullPointerException, but i want to design a solution that will gracefully resolve any possible problem on the web application in order to display a user friendly message to the user.
See the HandlerInterceptor interface instead. You'll want the afterCompletion method. You can then intercept the response and then set the appropriate header information to redirect to a container-configured error web page. You're right that Spring doesn't have this functionality, this is going to have to be specified by the web.xml which determines which codes map to which pages.
I have not worked with this particular bit of the spring framework, but the docs say
"Interface to be implemented by objects than can resolve exceptions thrown during handler mapping or execution, in the typical case to error views. Implementors are typically registered as beans in the application context.
Error views are analogous to the error page JSPs, but can be used with any kind of exception including any checked exception, with potentially fine-granular mappings for specific handlers."
so I'd imagine that given that NullPointer extends RuntimeException the framework isn't designed to catch it. Is there a reason the exception(s) can't be handled in the controller directly?

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