前言
ControllerAdvice非常好用，可以把系统内部的异常统一处理。用起来也很简单。比如，http://www.cnblogs.com/woshimrf/p/spring-web-400.html
而Spring提供了一个base类ResponseEntityExceptionHandler，可以使用这个来处理。但用的时候要注意，不要重复定义异常捕获，对于base里已经定义好的，只要overwrite就好，不要重复声明异常拦截。
以下来自stackoverflow
问题
@ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
private Logger log = LoggerFactory.getLogger(RestResponseEntityExceptionHandler.class);
@Autowired
private ApplicationContext applicationContext;
@ExceptionHandler({ ConstraintViolationException.class })
@ResponseStatus(HttpStatus.BAD_REQUEST)
@ResponseBody
public ErrorWrapper handleConstraintViolationException(ConstraintViolationException e) {
String fieldName = e.getConstraintName();
String message = getResourceMessage(fieldName + ".alreadyExists", "Already Exists");
return new ErrorWrapper(fieldName + ".error", message);
}
@ExceptionHandler({ MethodArgumentNotValidException.class })
@ResponseStatus(HttpStatus.BAD_REQUEST)
@ResponseBody
public ErrorWrapper handleMethodArgumentNotValidException(MethodArgumentNotValidException e) {
return new ErrorWrapper(".error", "test");
}
private String getResourceMessage(String key, String defaultMessage) {
String message = applicationContext.getMessage(key, null, Locale.getDefault());
if (StringUtils.isNotEmpty(message)) {
return message;
}
return defaultMessage;
}
}
将会得到以下异常：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0': Invocation of init method failed; nested exception is java.lang.IllegalStateException: Ambiguous @ExceptionHandler method mapped for [class org.springframework.web.bind.MethodArgumentNotValidException]: {public com.ca.bean.ErrorWrapper com.ca.exceptionHandler.RestResponseEntityExceptionHandler.handleMethodArgumentNotValidException(org.springframework.web.bind.MethodArgumentNotValidException), public final org.springframework.http.ResponseEntity org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler.handleException(java.lang.Exception,org.springframework.web.context.request.WebRequest)}
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:775) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861) ~[spring-context-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444) ~[spring-web-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326) ~[spring-web-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107) [spring-web-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5099) [catalina.jar:7.0.70]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5615) [catalina.jar:7.0.70]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) [catalina.jar:7.0.70]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571) [catalina.jar:7.0.70]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561) [catalina.jar:7.0.70]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_92]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_92]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_92]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_92]
Caused by: java.lang.IllegalStateException: Ambiguous @ExceptionHandler method mapped for [class org.springframework.web.bind.MethodArgumentNotValidException]: {public com.ca.bean.ErrorWrapper com.ca.exceptionHandler.RestResponseEntityExceptionHandler.handleMethodArgumentNotValidException(org.springframework.web.bind.MethodArgumentNotValidException), public final org.springframework.http.ResponseEntity org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler.handleException(java.lang.Exception,org.springframework.web.context.request.WebRequest)}
at org.springframework.web.method.annotation.ExceptionHandlerMethodResolver.addExceptionMapping(ExceptionHandlerMethodResolver.java:109) ~[spring-web-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.method.annotation.ExceptionHandlerMethodResolver.<init>(ExceptionHandlerMethodResolver.java:76) ~[spring-web-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver.initExceptionHandlerAdviceCache(ExceptionHandlerExceptionResolver.java:265) ~[spring-webmvc-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver.afterPropertiesSet(ExceptionHandlerExceptionResolver.java:241) ~[spring-webmvc-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) ~[spring-beans-4.3.0.RELEASE.jar:4.3.0.RELEASE]
... 21 common frames omitted
异常堆栈标明，重复定义了异常拦截。那么如果继承了ResponseEntityExceptionHandler之后，想修改某些内容怎么办呢？
答案
只要重写父类方法即可。不要在重写的方法上声明拦截异常。
对于ResponseEntityExceptionHandler已经定义好的异常，不需要重新定义，只要重写方法就可以了。
唯有不断学习方能改变！ --
Ryan Miao
