LindseyZhang / easy-spring-exception-handler

A plug and play global exception handler on spring web to throw custom exception

A plug and play Global exception handler on spring web

when throw a exception in spring web, spring always wrapper it as an internal error with status error code 500, which is not very friendly.

This small util helps you to throw custom exception with given http status that consistent with standard exception format but away you from boilerplate exception handling code.

Main class

BusinessException: our exception class. we provide four constructor.

    public BusinessException(String errorCode);

    public BusinessException(String errorCode, HttpStatus httpStatus);

    public BusinessException(String errorCode, Object modelInfo);

    public BusinessException(String errorCode, HttpStatus httpStatus, Object modelInfo);

if HttpStatus is not provided, then the default HttpStatus is 400:BAD_REQUEST.

modelInfo allow you to put any thing that you want to throw in the exception, which will show in the exception body as an extra.

How to use it

1. add dependency.
   in gradle

      compile('com.github.lindseyzhang:easy-spring-exception-handler:2.0.0')
   

   in maven

   <dependency>
       <groupId>com.github.lindseyzhang</groupId>
       <artifactId>easy-spring-exception-handler</artifactId>
       <version>2.0.0</version>
   </dependency>
   

2. add you own errorCode enum class.

   public enum ErrorCode {
       PRODUCT_ALREADY_EXIST;
   }
   

3. throw a BusinessException in Code.

       public void addProduct(Product product) {
   
           Product oldProduct = productRepository.findByName(product.getName());
           if (oldProduct != null) {
               throw new BusinessException(ErrorCode.PRODUCT_ALREADY_EXIST.name(), oldProduct);
           }
           productRepository.save(product);
       }
   

4. make spring scan this handler by config the @ComponentScan

   @SpringBootApplication
   @ComponentScan({"com.test.demo", "com.zlp.util.exception"})
   public class Application {
   
       public static void main(String[] args) {
           SpringApplication.run(Application.class, args);
       }
   
   }
   

   in @ComponentScan, you should add this exception handler's package to the scan path, which is com.zlp.util.exception, and the application's root package, in my case is com.test.demo or any other your scan path.

support for i18n

This simple library also support i18n, you can simply add messages.properties under resource package to use it.

eg: with ErrorKey class

    public enum ErrorCode {
        PRODUCT_ALREADY_EXIST;
    }

the messages.properties may look like this.

PRODUCT_ALREADY_EXIST=product already exist!

the ErrorMessage value will be use as the key in messages.properties, if the key can't find in messages.properties, then the default message will be the errorMessage. In this case the PRODUCT_EXCEED_VOLUME exception's error message will be product_exceed_volume.

the messages.properties without the locale info will use as default. if you want to resolve message against specific language and country, named the file like messages_lang_countryCode.properties. For example, for chinese, add a new properties file named messages_zh_CN.properties under resource package. see here for more i18n information