paulc4 / mvc-exceptions

Demo of points covered on my MVC Exceptions blog

mvc-exceptions

Project Overview

• Last updated January 2021
• This project is built using release 2.4.2 of Spring Boot, Java 8 and Spring 5.3.3 - see pom.xml.
• Web pages use Thymeleaf 3.0.12 and Bootstrap 4.5.3.
• The POM builds a JAR file, not a WAR, so you must run it as a Java application. Use mvn exec:java or mvn spring-boot:run to run it, then goto http://localhost:8080.
• If you wish to build a WAR, see pom-war.xml

This application demos most of the points covered on my MVC Exceptions blog:

• https://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc.

Release History

• November 2013: V1
• October 2014: V2
• April 2018: V2.0.1
• January 2021: V2.1.0

Application Overview

The most significant files are:

Demo 1

Controller with @ExceptionHandler methods

• src/main/java/demo1/web/ExceptionHandlingController.java
  • A controller that raises exceptions and provides its own handlers to catch and process them.

Demo 2

Controller relying on a ControllerAdvice to handle its exceptions.

• src/main/java/demo2/web/ControllerWithoutExceptionHandlers.java

  • A controller with all the same handlers as ExceptionHandlingController (so they all throw exceptions) but no handler methods.

• src/main/java/demo2/web/GlobalControllerExceptionHandler.java

  • @ControllerAdvice class with all the same handlers as ExceptionHandlingController, but they would apply to all controllers.

Demo 3 and 4

Exception handling using a SimpleMappingExceptionResolver. When running in demo mode (profile is set to demo-config, which is setup by default), it defines a SimpleMappingExceptionResolver subclass that can be enabled (Demo 3) or disabled (Demo 4) to show the difference.

• src/main/java/demo3/config/DemoExceptionConfiguration.java
  • Java configuration to setup the beans for this demo.
• src/main/java/demo3/web/ExceptionThrowingController.java
  • Controller used by the demo.
• src/main/java/demo3/web/SwitchableSimpleMappingExceptionResolver.java
  • The resolver subclass described above.
• src/main/java/demo3/web/ExceptionThrowingController.java
  • Controller that provides /simpleMappingExceptionResolver/on and /simpleMappingExceptionResolver/off for switching the resolver on/off.

Demo 5

• ReturnOrRedirectController
  • Controller highlighting how Spring Boot implements its error-page mechanism.

Exceptions

• src/main/java/demo/exceptions/CustomException.java
• src/main/java/demo/exceptions/DatabaseException.java
• src/main/java/demo/exceptions/InvalidCreditCardException.java
• src/main/java/demo/exceptions/OrderNotFoundException.java
• src/main/java/demo/exceptions/UnhandledException.java
  • Custom exceptions - see blog for usage.
• src/main/java/org/springframework/dao/DataAccessException.java
  • Example of a predefined annotation, copied from Spring.
• src/main/java/org/springframework/dao/DataIntegrityViolationException.java
  • Example of a predefined annotation, copied from Spring.

Application Setup

The Demo configuration profile is useful for this demo application, but not typical. So two other profiles are provided to configure a SimpleMappingExceptionResolver in a more typical way using either Java configuration or an XML bean file.

• src/main/java/demo/main/Main.java
  • Main entry point for the application. Can run as a Java application (using an embedded Tomcat container) or as a WAR inside a container. Sets a few initialization properties and Spring Bean profile to use. Available profiles are demo-config (default), java-config, xml-config.
• src/main/java/demo/main/Profiles.java
  • The Spring Bean profiles used in the application.
• src/main/java/demo/config/ExceptionConfiguration.java
  • Java configuration class to setup a SimpleMappingExceptionResolver. Only used if the java-config profile is active.
• src/main/resources/mvc-configuration.xml
  • XML alternative to ExceptionConfiguration. Also sets up a SimpleMappingExceptionResolver. Only used if the xml-config profile is active.
• src/main/java/demo/config/ResponseDataControllerAdvice
  • Controller advice that puts useful data into the model for every request.

Utility Classes

• src/main/java/demo/utils/BeanLogger.java
  • Simple BeanPostProcessor to log all beans created. Not required by the demo, but as Spring Boot does so much, it allows all the beans created to be easily logged. And a lot less output than enabling debug=true.

Templates

All the views used, generated via Thymeleaf.

• Error views

  • src/main/resources/templates/creditCardError.html
  • src/main/resources/templates/databaseError.html
  • src/main/resources/templates/databaseException.html
  • src/main/resources/templates/error.html
  • src/main/resources/templates/exceptionPage.html
  • src/main/resources/templates/support.html

• Web Pages

  • src/main/resources/templates/index.html - Home page
  • src/main/resources/templates/local.html - Demo 1
  • src/main/resources/templates/global.html - Demo 2
  • src/main/resources/templates/unannotated.html - Demo 3
  • src/main/resources/templates/nohandler.html - Demo 4
  • src/main/resources/templates/demo5.html - Demo 5

Build

• pom.xml

  • Maven POM - notice how short it is - Spring Boot does most of the work. However heed the comments in the file.
  • Build in the usual way: mvn package to create an executable JAR with embedded Tomcat.
  • You can also run the demo using java -jar target/mvc-exceptions-2.0.1-RELEASE.jar

• pom-war.xml - If you prefer to build a traditional WAR file instead of an executable JAR.

  • Build using mvn -f pom-war.xml package

Examples

Not used by the application, but provided as sample code.

• src/main/java/demo/example/ExampleExceptionHandlerExceptionResolver.java
  • Unused in the demo (to keep it simple), but implements the example discussed in the blog.
• src/main/java/demo/example/ExampleSimpleMappingExceptionResolver.java
  • Unused in the demo (to keep it simple), but implements the example shown in the blog (called MySimpleMappingExceptionResolver in the blog article).

mvc-exceptions's Issues

Compile error due to wrong override in Main.java

Hi,

trying to compile the demo app I get the following error:

[ERROR] return type void is not compatible with org.springframework.boot.builder.SpringApplicationBuilder

Seems that protected void configure(SpringApplicationBuilder application) in Main.java is wrong and should be declared as
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) instead?

Or did the interface of SpringApplicationBuilder change recently and I just have a wrong superclass?

Best regards

Marcus

Unnecessary (and slightly confusing) import in demo 2?

I'm not sure this line should appear in your demo2 GlobalExceptionHandlingControllerAdvice class.

import demo1.web.ExceptionHandlingController;

But I'm new to this stuff. I could be missing something.

Update to Spring Boot 1.1.6.RELEASE

Can we please update this project to Spring Boot 1.1.6.RELEASE

Compilation issue, surefire plugin version missing, no examples of handling filter related exceptions

This is not an issue, but it would be nice if you had at least ONE example of how to handle exceptions that propagate at filter level, all of the examples defined here only discuss handling exceptions originating from controllers. Other components especially filters, example: Spring security related filters, often throw exceptions that are not caught by these handlers. Could you post few examples/best practices on how to catch filter exceptions and return appropriate content type messages?

Besides this there is a compilation issue in Main class and one of the surefire plugins is missing in default repo, had to manually install this plugin.
[ERROR] Plugin org.apache.maven.plugins:maven-surefire-plugin:2.15 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-surefire-plugin:jar:2.15: The repository system is ...
...
Caused by: org.sonatype.aether.resolution.ArtifactResolutionException: The repository system is offline but the artifact org.apache.maven.plugins:maven-surefire-plugin:pom:2.15 is not available in the local repository.
at org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:538)

Exception handling for Shiro permissions

I want to know if there is a unified exception handling for Shiro's insufficient permissions? Or will it be added in the future?