Spring MVC:ツールException Handler Exception Resolaver
概要は、要求を完全に処理し、その後、処理要求を継続する必要がない. は
ソースコードバージョン: Spring MVCコンセプトモデル–インターフェースHandlerException Resolover Spring MVC:ツールDefault Handler Exception Resolover Spring MVC:ツールResonseStatus Exception Resolover Spring MVC:ツールSimpleMappingException Resolover Spring MVC:WebMvcConfigrationSupportで定義されているHandlerException Resoliverコンポーネント How Spring Boot Initializes the Spring MVC Appplication Controt
Spring MVCは、実装されたHandlerExceptionResolverを内蔵しており、HandlerのタイプがHandlerMethodの中で異常が発生した場合、つまり@Controllerのコンポーネントクラスの@RequestMappingの方法における異常である.このような異常がExceptionHandlerExceptionResolverに解析されると、まず異常が発生したコントローラ方法の中に適切な@ExceptionHanlder方法があるかどうかを確認し、@ControllerAdvice類の中に適切な@ExceptionHanlder方法があるかどうかを確認します.この方法は異常な処理過程に対して、コントローラ方法のユーザー要求に対する処理と似ています.Spring MVC:コントローラ方法の処理要求のプロセス分析-0.概説では、結果は主に2つの大きな分岐があります.ExceptionHandlerExceptionResolverオブジェクトに戻り、その後、オブジェクトに基づいてビュー解析とレンダリングを継続する必要がある.ModelAndViewオブジェクトが空のオブジェクト(ModelAndViewが#isEmptyに戻る)であることは、使用者がデフォルトの解析メカニズムを使用することを示す.trueの使用位置: // DispatcherServlet
@Nullable
protected ModelAndView processHandlerException(HttpServletRequest request,
HttpServletResponse response,
@Nullable Object handler, Exception ex) throws Exception {
// Success and error responses may use different content types
request.removeAttribute(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE);
// Check registered HandlerExceptionResolvers...
ModelAndView exMv = null;
if (this.handlerExceptionResolvers != null) {
// this.handlerExceptionResolvers
// ExceptionHandlerExceptionResolver
// this.handlerExceptionResolvers DispatcherServlet
// HandlerExceptionResolver bean ， bean
//
for (HandlerExceptionResolver resolver : this.handlerExceptionResolvers) {
exMv = resolver.resolveException(request, response, handler, ex);
if (exMv != null) {
break;
}
}
}
//
// ...
}
ソースコードバージョン:
ExceptionHandlerExceptionResolverpackage org.springframework.web.servlet.mvc.method.annotation;
// import
/**
* An {@link AbstractHandlerMethodExceptionResolver} that resolves exceptions
* through {@code @ExceptionHandler} methods.
*
* Support for custom argument and return value types can be added via
* {@link #setCustomArgumentResolvers} and {@link #setCustomReturnValueHandlers}.
* Or alternatively to re-configure all argument and return value types use
* {@link #setArgumentResolvers} and {@link #setReturnValueHandlers(List)}.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 3.1
*/
public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExceptionResolver
implements ApplicationContextAware, InitializingBean {
@Nullable
private List<HandlerMethodArgumentResolver> customArgumentResolvers;
@Nullable
private HandlerMethodArgumentResolverComposite argumentResolvers;
@Nullable
private List<HandlerMethodReturnValueHandler> customReturnValueHandlers;
@Nullable
private HandlerMethodReturnValueHandlerComposite returnValueHandlers;
// HttpMessageConverter
// HandlerMethodReturnValueHandler
private List<HttpMessageConverter<?>> messageConverters;
private ContentNegotiationManager contentNegotiationManager = new ContentNegotiationManager();
// Advice ， ，
private final List<Object> responseBodyAdvice = new ArrayList<>();
@Nullable
private ApplicationContext applicationContext;
// @ExceptionHandler
private final Map<Class<?>, ExceptionHandlerMethodResolver> exceptionHandlerCache =
new ConcurrentHashMap<>(64);
// @ControllerAdvice bean @ExceptionHandler
private final Map<ControllerAdviceBean, ExceptionHandlerMethodResolver>
exceptionHandlerAdviceCache = new LinkedHashMap<>();
public ExceptionHandlerExceptionResolver() {
// this.messageConverters, :
// 1. ByteArrayHttpMessageConverter
// 2. StringHttpMessageConverter, ISO8859-1 ，
// 3. SourceHttpMessageConverter , DOMSource/SAXSource/StAXSource/StreamSource
// 4. AllEncompassingFormHttpMessageConverter ,UTF-8， multipart ，
// FormHttpMessageConverter ， XML/JSON
StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter();
stringHttpMessageConverter.setWriteAcceptCharset(false); // see SPR-7316
this.messageConverters = new ArrayList<>();
this.messageConverters.add(new ByteArrayHttpMessageConverter());
this.messageConverters.add(stringHttpMessageConverter);
try {
this.messageConverters.add(new SourceHttpMessageConverter<>());
}
catch (Error err) {
// Ignore when no TransformerFactory implementation is available
}
this.messageConverters.add(new AllEncompassingFormHttpMessageConverter());
}
/**
* Provide resolvers for custom argument types. Custom resolvers are ordered
* after built-in ones. To override the built-in support for argument
* resolution use {@link #setArgumentResolvers} instead.
*/
public void setCustomArgumentResolvers(@Nullable List<HandlerMethodArgumentResolver>
argumentResolvers) {
this.customArgumentResolvers= argumentResolvers;
}
/**
* Return the custom argument resolvers, or {@code null}.
*/
@Nullable
public List<HandlerMethodArgumentResolver> getCustomArgumentResolvers() {
return this.customArgumentResolvers;
}
/**
* Configure the complete list of supported argument types thus overriding
* the resolvers that would otherwise be configured by default.
*/
public void setArgumentResolvers(
@Nullable List<HandlerMethodArgumentResolver> argumentResolvers) {
if (argumentResolvers == null) {
this.argumentResolvers = null;
}
else {
this.argumentResolvers = new HandlerMethodArgumentResolverComposite();
this.argumentResolvers.addResolvers(argumentResolvers);
}
}
/**
* Return the configured argument resolvers, or possibly {@code null} if
* not initialized yet via {@link #afterPropertiesSet()}.
*/
@Nullable
public HandlerMethodArgumentResolverComposite getArgumentResolvers() {
return this.argumentResolvers;
}
/**
* Provide handlers for custom return value types. Custom handlers are
* ordered after built-in ones. To override the built-in support for
* return value handling use {@link #setReturnValueHandlers}.
*/
public void setCustomReturnValueHandlers(
@Nullable List<HandlerMethodReturnValueHandler> returnValueHandlers) {
this.customReturnValueHandlers = returnValueHandlers;
}
/**
* Return the custom return value handlers, or {@code null}.
*/
@Nullable
public List<HandlerMethodReturnValueHandler> getCustomReturnValueHandlers() {
return this.customReturnValueHandlers;
}
/**
* Configure the complete list of supported return value types thus
* overriding handlers that would otherwise be configured by default.
*/
public void setReturnValueHandlers(
@Nullable List<HandlerMethodReturnValueHandler> returnValueHandlers) {
if (returnValueHandlers == null) {
this.returnValueHandlers = null;
}
else {
this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite();
this.returnValueHandlers.addHandlers(returnValueHandlers);
}
}
/**
* Return the configured handlers, or possibly {@code null} if not
* initialized yet via {@link #afterPropertiesSet()}.
*/
@Nullable
public HandlerMethodReturnValueHandlerComposite getReturnValueHandlers() {
return this.returnValueHandlers;
}
/**
* Set the message body converters to use.
* These converters are used to convert from and to HTTP requests and responses.
*/
public void setMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
this.messageConverters = messageConverters;
}
/**
* Return the configured message body converters.
*/
public List<HttpMessageConverter<?>> getMessageConverters() {
return this.messageConverters;
}
/**
* Set the {@link ContentNegotiationManager} to use to determine requested media types.
* If not set, the default constructor is used.
*/
public void setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) {
this.contentNegotiationManager = contentNegotiationManager;
}
/**
* Return the configured {@link ContentNegotiationManager}.
*/
public ContentNegotiationManager getContentNegotiationManager() {
return this.contentNegotiationManager;
}
/**
* Add one or more components to be invoked after the execution of a controller
* method annotated with {@code @ResponseBody} or returning {@code ResponseEntity}
* but before the body is written to the response with the selected
* {@code HttpMessageConverter}.
*/
public void setResponseBodyAdvice(@Nullable List<ResponseBodyAdvice<?>> responseBodyAdvice) {
this.responseBodyAdvice.clear();
if (responseBodyAdvice != null) {
this.responseBodyAdvice.addAll(responseBodyAdvice);
}
}
@Override
public void setApplicationContext(@Nullable ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
@Nullable
public ApplicationContext getApplicationContext() {
return this.applicationContext;
}
// InitializingBean
@Override
public void afterPropertiesSet() {
// Do this first, it may add ResponseBodyAdvice beans
initExceptionHandlerAdviceCache();
if (this.argumentResolvers == null) {
List<HandlerMethodArgumentResolver> resolvers = getDefaultArgumentResolvers();
this.argumentResolvers =
new HandlerMethodArgumentResolverComposite().addResolvers(resolvers);
}
if (this.returnValueHandlers == null) {
List<HandlerMethodReturnValueHandler> handlers = getDefaultReturnValueHandlers();
this.returnValueHandlers =
new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers);
}
}
private void initExceptionHandlerAdviceCache() {
if (getApplicationContext() == null) {
return;
}
// @ControllerAdvice bean
List<ControllerAdviceBean> adviceBeans =
ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());
AnnotationAwareOrderComparator.sort(adviceBeans);
for (ControllerAdviceBean adviceBean : adviceBeans) {
Class<?> beanType = adviceBean.getBeanType();
if (beanType == null) {
throw new IllegalStateException(
"Unresolvable type for ControllerAdviceBean: " + adviceBean);
}
// ExceptionHandlerMethodResolver ， ，
// @ExceptionHandler ，
ExceptionHandlerMethodResolver resolver = new ExceptionHandlerMethodResolver(beanType);
if (resolver.hasExceptionMappings()) {
// resolver beanType， @ExceptionHandler ，
// this.exceptionHandlerAdviceCache
this.exceptionHandlerAdviceCache.put(adviceBean, resolver);
}
if (ResponseBodyAdvice.class.isAssignableFrom(beanType)) {
// @ControllerAdvice bean ResponseBodyAdvice ，
// this.responseBodyAdvice
this.responseBodyAdvice.add(adviceBean);
}
}
if (logger.isDebugEnabled()) {
int handlerSize = this.exceptionHandlerAdviceCache.size();
int adviceSize = this.responseBodyAdvice.size();
if (handlerSize == 0 && adviceSize == 0) {
logger.debug("ControllerAdvice beans: none");
}
else {
logger.debug("ControllerAdvice beans: " +
handlerSize + " @ExceptionHandler, " + adviceSize + " ResponseBodyAdvice");
}
}
}
/**
* Return an unmodifiable Map with the {@link ControllerAdvice @ControllerAdvice}
* beans discovered in the ApplicationContext. The returned map will be empty if
* the method is invoked before the bean has been initialized via
* {@link #afterPropertiesSet()}.
*/
public Map<ControllerAdviceBean, ExceptionHandlerMethodResolver>
getExceptionHandlerAdviceCache() {
return Collections.unmodifiableMap(this.exceptionHandlerAdviceCache);
}
/**
* HandlerMethodArgumentResolver ，
*
* Return the list of argument resolvers to use including built-in resolvers
* and custom resolvers provided via {@link #setCustomArgumentResolvers}.
*/
protected List<HandlerMethodArgumentResolver> getDefaultArgumentResolvers() {
List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>();
// Annotation-based argument resolution
// ，
resolvers.add(new SessionAttributeMethodArgumentResolver());
resolvers.add(new RequestAttributeMethodArgumentResolver());
// Type-based argument resolution
// ，
resolvers.add(new ServletRequestMethodArgumentResolver());
resolvers.add(new ServletResponseMethodArgumentResolver());
resolvers.add(new RedirectAttributesMethodArgumentResolver());
resolvers.add(new ModelMethodProcessor());
// Custom arguments
// ，
if (getCustomArgumentResolvers() != null) {
resolvers.addAll(getCustomArgumentResolvers());
}
return resolvers;
}
/**
* HandlerMethodReturnValueHandler
*
* Return the list of return value handlers to use including built-in and
* custom handlers provided via {@link #setReturnValueHandlers}.
*/
protected List<HandlerMethodReturnValueHandler> getDefaultReturnValueHandlers() {
List<HandlerMethodReturnValueHandler> handlers = new ArrayList<>();
// Single-purpose return value types
handlers.add(new ModelAndViewMethodReturnValueHandler());
handlers.add(new ModelMethodProcessor());
handlers.add(new ViewMethodReturnValueHandler());
handlers.add(new HttpEntityMethodProcessor(
getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));
// Annotation-based return value types
handlers.add(new ModelAttributeMethodProcessor(false));
handlers.add(new RequestResponseBodyMethodProcessor(
getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));
// Multi-purpose return value types
handlers.add(new ViewNameMethodReturnValueHandler());
handlers.add(new MapMethodProcessor());
// Custom return value types
if (getCustomReturnValueHandlers() != null) {
handlers.addAll(getCustomReturnValueHandlers());
}
// Catch-all
//
handlers.add(new ModelAttributeMethodProcessor(true));
return handlers;
}
/**
* Find an {@code @ExceptionHandler} method and invoke it to handle the raised exception.
*/
@Override
@Nullable
protected ModelAndView doResolveHandlerMethodException(HttpServletRequest request,
HttpServletResponse response, @Nullable HandlerMethod handlerMethod,
Exception exception) {
// exception ， @ControllerAdvice
// @ExceptionHandler ， ，
// ， ， null，
ServletInvocableHandlerMethod exceptionHandlerMethod = getExceptionHandlerMethod(
handlerMethod, exception);
if (exceptionHandlerMethod == null) {
return null;
}
// exception ，
// exceptionHandlerMethod , :
// 1. : ，
// 2. mavContainer
// 3.
if (this.argumentResolvers != null) {
exceptionHandlerMethod.setHandlerMethodArgumentResolvers(this.argumentResolvers);
}
if (this.returnValueHandlers != null) {
exceptionHandlerMethod.setHandlerMethodReturnValueHandlers(this.returnValueHandlers);
}
ServletWebRequest webRequest = new ServletWebRequest(request, response);
ModelAndViewContainer mavContainer = new ModelAndViewContainer();
//
try {
if (logger.isDebugEnabled()) {
logger.debug("Using @ExceptionHandler " + exceptionHandlerMethod);
}
Throwable cause = exception.getCause();
if (cause != null) {
// Expose cause as provided argument as well
exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer,
exception, cause, handlerMethod);
}
else {
// Otherwise, just the given exception as-is
exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, exception,
handlerMethod);
}
}
catch (Throwable invocationEx) {
// Any other than the original exception is unintended here,
// probably an accident (e.g. failed assertion or the like).
if (invocationEx != exception && logger.isWarnEnabled()) {
logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
}
// Continue with default processing of the original exception...
// ， null，
// ， ， exception，
// invocationEx
return null;
}
if (mavContainer.isRequestHandled()) {
// ， ModelAndView() ，
//
return new ModelAndView();
}
else {
// ， ， ModelAndView,
//
ModelMap model = mavContainer.getModel();
HttpStatus status = mavContainer.getStatus();
ModelAndView mav = new ModelAndView(mavContainer.getViewName(), model, status);
mav.setViewName(mavContainer.getViewName());
if (!mavContainer.isViewReference()) {
mav.setView((View) mavContainer.getView());
}
if (model instanceof RedirectAttributes) {
Map<String, ?> flashAttributes = ((RedirectAttributes) model).getFlashAttributes();
RequestContextUtils.getOutputFlashMap(request).putAll(flashAttributes);
}
return mav;
}
}
/**
* Find an {@code @ExceptionHandler} method for the given exception. The default
* implementation searches methods in the class hierarchy of the controller first
* and if not found, it continues searching for additional {@code @ExceptionHandler}
* methods assuming some {@linkplain ControllerAdvice @ControllerAdvice}
* Spring-managed beans were detected.
* @param handlerMethod the method where the exception was raised (may be {@code null})
* @param exception the raised exception
* @return a method to handle the exception, or {@code null} if none
*/
@Nullable
protected ServletInvocableHandlerMethod getExceptionHandlerMethod(
@Nullable HandlerMethod handlerMethod, Exception exception) {
Class<?> handlerType = null;
if (handlerMethod != null) {
// Local exception handler methods on the controller class itself.
// To be invoked through the proxy, even in case of an interface-based proxy.
// @ExceptionHander,
// @ControllerAdvice ，
// ExceptionHandlerMethodResolver
handlerType = handlerMethod.getBeanType();
ExceptionHandlerMethodResolver resolver = this.exceptionHandlerCache.get(handlerType);
if (resolver == null) {
resolver = new ExceptionHandlerMethodResolver(handlerType);
this.exceptionHandlerCache.put(handlerType, resolver);
}
// exception ，
// ServletInvocableHandlerMethod，
Method method = resolver.resolveMethod(exception);
if (method != null) {
return new ServletInvocableHandlerMethod(handlerMethod.getBean(), method);
}
// For advice applicability check below (involving base packages, assignable types
// and annotation presence), use target class instead of interface-based proxy.
if (Proxy.isProxyClass(handlerType)) {
handlerType = AopUtils.getTargetClass(handlerMethod.getBean());
}
}
// exception ，
// @ControllerAdvice exception
// ， ServletInvocableHandlerMethod
// ，
for (Map.Entry<ControllerAdviceBean, ExceptionHandlerMethodResolver> entry
: this.exceptionHandlerAdviceCache.entrySet()) {
ControllerAdviceBean advice = entry.getKey();
if (advice.isApplicableToBeanType(handlerType)) {
ExceptionHandlerMethodResolver resolver = entry.getValue();
Method method = resolver.resolveMethod(exception);
if (method != null) {
return new ServletInvocableHandlerMethod(advice.resolveBean(), method);
}
}
}
// exception @ControllerAdvice
// ， null， ：
// ， HandlerExceptionResolver ？
return null;
}
}