背景
- 介紹Interceptor的案例桑腮。
- Interceptor的解析，HandlerMapping和Interceptor的綁定吴攒。
- HandlerExecutionChain的攔截器鏈的構(gòu)建。
- HandlerExecutionChain的執(zhí)行流程砂蔽。
Interceptor案例
@Component
public class TimeInterceptor extends HandlerInterceptorAdapter {
private final NamedThreadLocal<Long> startTimeThreadLocal = new NamedThreadLocal<>("startTimeThreadLocal");
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("time interceptor postHandle");
// 獲取處理當(dāng)前請求的 handler 信息
HandlerMethod handlerMethod = (HandlerMethod) handler;
System.out.println("handler 類：" + handlerMethod.getBeanType().getName());
System.out.println("handler 方法：" + handlerMethod.getMethod().getName());
MethodParameter[] methodParameters = handlerMethod.getMethodParameters();
for (MethodParameter methodParameter : methodParameters) {
// 只能獲取參數(shù)的名稱洼怔，不能獲取到參數(shù)的值
String parameterName = methodParameter.getParameterName();
System.out.println("parameterName: " + parameterName);
}
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("time interceptor postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("time interceptor afterCompletion");
}
}
- 通過繼承HandlerInterceptorAdapter實現(xiàn)攔截器類并實現(xiàn)preHandle、postHandle左驾、afterCompletion等方法镣隶。
<bean id="xxxx" class="com.lg.mvc.interceptor.TimeInterceptor"/>
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="xxx"/>
<mvc:exclude-mapping path="xxxx"/>
<ref bean="logMvcInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
- 通過在xml文件中定義mvc:interceptors定義攔截器和對應(yīng)匹配的路徑。
- 通過interceptor標(biāo)簽的InterceptorsBeanDefinitionParser解析攔截器定義诡右。
Interceptor解析流程
http\://www.springframework.org/schema/mvc=org.springframework.web.servlet.config.MvcNamespaceHandler
public class MvcNamespaceHandler extends NamespaceHandlerSupport {
@Override
public void init() {
registerBeanDefinitionParser("annotation-driven", new AnnotationDrivenBeanDefinitionParser());
registerBeanDefinitionParser("default-servlet-handler", new DefaultServletHandlerBeanDefinitionParser());
registerBeanDefinitionParser("interceptors", new InterceptorsBeanDefinitionParser());
registerBeanDefinitionParser("resources", new ResourcesBeanDefinitionParser());
registerBeanDefinitionParser("view-controller", new ViewControllerBeanDefinitionParser());
registerBeanDefinitionParser("redirect-view-controller", new ViewControllerBeanDefinitionParser());
registerBeanDefinitionParser("status-controller", new ViewControllerBeanDefinitionParser());
registerBeanDefinitionParser("view-resolvers", new ViewResolversBeanDefinitionParser());
registerBeanDefinitionParser("tiles-configurer", new TilesConfigurerBeanDefinitionParser());
registerBeanDefinitionParser("freemarker-configurer", new FreeMarkerConfigurerBeanDefinitionParser());
registerBeanDefinitionParser("velocity-configurer", new VelocityConfigurerBeanDefinitionParser());
registerBeanDefinitionParser("groovy-configurer", new GroovyMarkupConfigurerBeanDefinitionParser());
registerBeanDefinitionParser("script-template-configurer", new ScriptTemplateConfigurerBeanDefinitionParser());
registerBeanDefinitionParser("cors", new CorsBeanDefinitionParser());
}
}
- 通過InterceptorsBeanDefinitionParser來解析interceptors的配置項安岂。
class InterceptorsBeanDefinitionParser implements BeanDefinitionParser {
@Override
public BeanDefinition parse(Element element, ParserContext parserContext) {
CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
parserContext.pushContainingComponent(compDefinition);
RuntimeBeanReference pathMatcherRef = null;
if (element.hasAttribute("path-matcher")) {
pathMatcherRef = new RuntimeBeanReference(element.getAttribute("path-matcher"));
}
List<Element> interceptors = DomUtils.getChildElementsByTagName(element, "bean", "ref", "interceptor");
for (Element interceptor : interceptors) {
RootBeanDefinition mappedInterceptorDef = new RootBeanDefinition(MappedInterceptor.class);
mappedInterceptorDef.setSource(parserContext.extractSource(interceptor));
mappedInterceptorDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
ManagedList<String> includePatterns = null;
ManagedList<String> excludePatterns = null;
Object interceptorBean;
if ("interceptor".equals(interceptor.getLocalName())) {
includePatterns = getIncludePatterns(interceptor, "mapping");
excludePatterns = getIncludePatterns(interceptor, "exclude-mapping");
Element beanElem = DomUtils.getChildElementsByTagName(interceptor, "bean", "ref").get(0);
interceptorBean = parserContext.getDelegate().parsePropertySubElement(beanElem, null);
}
else {
interceptorBean = parserContext.getDelegate().parsePropertySubElement(interceptor, null);
}
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(0, includePatterns);
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(1, excludePatterns);
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(2, interceptorBean);
if (pathMatcherRef != null) {
mappedInterceptorDef.getPropertyValues().add("pathMatcher", pathMatcherRef);
}
String beanName = parserContext.getReaderContext().registerWithGeneratedName(mappedInterceptorDef);
parserContext.registerComponent(new BeanComponentDefinition(mappedInterceptorDef, beanName));
}
parserContext.popAndRegisterContainingComponent();
return null;
}
}
- 解析Interceptor的xml配置生成MappedInterceptor的BeanDefinition。
- 每個mvc:interceptor標(biāo)簽解析生成一個MappedInterceptor對象帆吻。
public final class MappedInterceptor implements HandlerInterceptor {
private final String[] includePatterns;
private final String[] excludePatterns;
private final HandlerInterceptor interceptor;
private PathMatcher pathMatcher;
public MappedInterceptor(String[] includePatterns, HandlerInterceptor interceptor) {
this(includePatterns, null, interceptor);
}
public MappedInterceptor(String[] includePatterns, String[] excludePatterns, HandlerInterceptor interceptor) {
this.includePatterns = includePatterns;
this.excludePatterns = excludePatterns;
this.interceptor = interceptor;
}
public MappedInterceptor(String[] includePatterns, WebRequestInterceptor interceptor) {
this(includePatterns, null, interceptor);
}
public MappedInterceptor(String[] includePatterns, String[] excludePatterns, WebRequestInterceptor interceptor) {
this(includePatterns, excludePatterns, new WebRequestHandlerInterceptorAdapter(interceptor));
}
public void setPathMatcher(PathMatcher pathMatcher) {
this.pathMatcher = pathMatcher;
}
public PathMatcher getPathMatcher() {
return this.pathMatcher;
}
public String[] getPathPatterns() {
return this.includePatterns;
}
public HandlerInterceptor getInterceptor() {
return this.interceptor;
}
public boolean matches(String lookupPath, PathMatcher pathMatcher) {
PathMatcher pathMatcherToUse = (this.pathMatcher != null ? this.pathMatcher : pathMatcher);
if (!ObjectUtils.isEmpty(this.excludePatterns)) {
for (String pattern : this.excludePatterns) {
if (pathMatcherToUse.match(pattern, lookupPath)) {
return false;
}
}
}
if (ObjectUtils.isEmpty(this.includePatterns)) {
return true;
}
for (String pattern : this.includePatterns) {
if (pathMatcherToUse.match(pattern, lookupPath)) {
return true;
}
}
return false;
}
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
return this.interceptor.preHandle(request, response, handler);
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
this.interceptor.postHandle(request, response, handler, modelAndView);
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
Exception ex) throws Exception {
this.interceptor.afterCompletion(request, response, handler, ex);
}
}
- MappedInterceptor包含includePatterns和excludePatterns和interceptor核心變量域那。
- includePatterns代表包含的匹配路徑，excludePatterns代表排除的匹配路徑猜煮，interceptor代表攔截器對象次员。
- matches方法負責(zé)查找Request匹配的Interceptor對象。
RequestMappingHandlerMapping
- HandlerMapping的構(gòu)建過程中會建立和Interceptors的關(guān)聯(lián)關(guān)系友瘤。
- RequestMappingHandlerMapping是HandlerMapping的一種實現(xiàn)形式翠肘。
- RequestMappingHandlerMapping的初始化過程中通過父類AbstractHandlerMapping負責(zé)建立和Interceptors的關(guān)聯(lián)關(guān)系。
public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport implements HandlerMapping, Ordered {
private Object defaultHandler;
private UrlPathHelper urlPathHelper = new UrlPathHelper();
private PathMatcher pathMatcher = new AntPathMatcher();
private final List<Object> interceptors = new ArrayList<Object>();
private final List<HandlerInterceptor> adaptedInterceptors = new ArrayList<HandlerInterceptor>();
private final UrlBasedCorsConfigurationSource globalCorsConfigSource = new UrlBasedCorsConfigurationSource();
private CorsProcessor corsProcessor = new DefaultCorsProcessor();
@Override
protected void initApplicationContext() throws BeansException {
extendInterceptors(this.interceptors);
detectMappedInterceptors(this.adaptedInterceptors);
initInterceptors();
}
protected void detectMappedInterceptors(List<HandlerInterceptor> mappedInterceptors) {
mappedInterceptors.addAll(
BeanFactoryUtils.beansOfTypeIncludingAncestors(
getApplicationContext(), MappedInterceptor.class, true, false).values());
}
}
- AbstractHandlerMapping的interceptors和adaptedInterceptors保存Interceptor辫秧。
- detectMappedInterceptors保存的是解析生成的MappedInterceptor類束倍。
HandlerExecutionChain
public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport implements HandlerMapping, Ordered {
private int order = Integer.MAX_VALUE; // default: same as non-Ordered
private Object defaultHandler;
private UrlPathHelper urlPathHelper = new UrlPathHelper();
private PathMatcher pathMatcher = new AntPathMatcher();
private final List<Object> interceptors = new ArrayList<Object>();
private final List<HandlerInterceptor> adaptedInterceptors = new ArrayList<HandlerInterceptor>();
private final UrlBasedCorsConfigurationSource globalCorsConfigSource = new UrlBasedCorsConfigurationSource();
private CorsProcessor corsProcessor = new DefaultCorsProcessor();
@Override
public final HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
Object handler = getHandlerInternal(request);
HandlerExecutionChain executionChain = getHandlerExecutionChain(handler, request);
return executionChain;
}
protected HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request) {
HandlerExecutionChain chain = (handler instanceof HandlerExecutionChain ?
(HandlerExecutionChain) handler : new HandlerExecutionChain(handler));
// 根據(jù)請求的path獲取interceptor
String lookupPath = this.urlPathHelper.getLookupPathForRequest(request);
for (HandlerInterceptor interceptor : this.adaptedInterceptors) {
if (interceptor instanceof MappedInterceptor) {
MappedInterceptor mappedInterceptor = (MappedInterceptor) interceptor;
// 匹配查找對應(yīng)的interceptor
if (mappedInterceptor.matches(lookupPath, this.pathMatcher)) {
chain.addInterceptor(mappedInterceptor.getInterceptor());
}
}
else {
chain.addInterceptor(interceptor);
}
}
return chain;
}
}
- AbstractHandlerMapping的getHandler方法返回HandlerExecutionChain的攔截器鏈。
- AbstractHandlerMapping的getHandlerExecutionChain遍歷adaptedInterceptors添加到HandlerExecutionChain中盟戏。
攔截器執(zhí)行流程
public class DispatcherServlet extends FrameworkServlet {
protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
HttpServletRequest processedRequest = request;
HandlerExecutionChain mappedHandler = null;
boolean multipartRequestParsed = false;
WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
try {
ModelAndView mv = null;
Exception dispatchException = null;
try {
processedRequest = checkMultipart(request);
multipartRequestParsed = (processedRequest != request);
// mappedHandler代表的是HandlerExecutionChain職責(zé)鏈
mappedHandler = getHandler(processedRequest);
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
// 執(zhí)行mappedHandler的applyPreHandle方法
if (!mappedHandler.applyPreHandle(processedRequest, response)) {
return;
}
// 執(zhí)行controller的執(zhí)行邏輯
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
if (asyncManager.isConcurrentHandlingStarted()) {
return;
}
applyDefaultViewName(processedRequest, mv);
// 執(zhí)行mappedHandler的applyPostHandle方法
mappedHandler.applyPostHandle(processedRequest, response, mv);
}
catch (Exception ex) {
}
processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
}
catch (Exception ex) {
}
finally {
}
}
protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
for (HandlerMapping hm : this.handlerMappings) {
// RequestMappingHandlerMapping
HandlerExecutionChain handler = hm.getHandler(request);
if (handler != null) {
return handler;
}
}
return null;
}
}
- mappedHandler.applyPreHandle負責(zé)執(zhí)行攔截器Interceptor的preHandle方法绪妹。
- ha.handle負責(zé)執(zhí)行controller的邏輯方法。
- mappedHandler.applyPostHandle負責(zé)執(zhí)行攔截器Interceptor的postHandle方法柿究。
public class HandlerExecutionChain {
private static final Log logger = LogFactory.getLog(HandlerExecutionChain.class);
private final Object handler;
private HandlerInterceptor[] interceptors;
private List<HandlerInterceptor> interceptorList;
private int interceptorIndex = -1;
public HandlerInterceptor[] getInterceptors() {
if (this.interceptors == null && this.interceptorList != null) {
this.interceptors = this.interceptorList.toArray(new HandlerInterceptor[this.interceptorList.size()]);
}
return this.interceptors;
}
boolean applyPreHandle(HttpServletRequest request, HttpServletResponse response) throws Exception {
HandlerInterceptor[] interceptors = getInterceptors();
if (!ObjectUtils.isEmpty(interceptors)) {
for (int i = 0; i < interceptors.length; i++) {
HandlerInterceptor interceptor = interceptors[i];
if (!interceptor.preHandle(request, response, this.handler)) {
triggerAfterCompletion(request, response, null);
return false;
}
this.interceptorIndex = i;
}
}
return true;
}
void applyPostHandle(HttpServletRequest request, HttpServletResponse response, ModelAndView mv) throws Exception {
HandlerInterceptor[] interceptors = getInterceptors();
if (!ObjectUtils.isEmpty(interceptors)) {
for (int i = interceptors.length - 1; i >= 0; i--) {
HandlerInterceptor interceptor = interceptors[i];
interceptor.postHandle(request, response, this.handler, mv);
}
}
}
void triggerAfterCompletion(HttpServletRequest request, HttpServletResponse response, Exception ex)
throws Exception {
HandlerInterceptor[] interceptors = getInterceptors();
if (!ObjectUtils.isEmpty(interceptors)) {
for (int i = this.interceptorIndex; i >= 0; i--) {
HandlerInterceptor interceptor = interceptors[i];
try {
interceptor.afterCompletion(request, response, this.handler, ex);
}
catch (Throwable ex2) {
}
}
}
}
}
- applyPreHandle負責(zé)遍歷攔截器的preHandle方法邮旷。
- applyPostHandle負責(zé)遍歷攔截器的postHandle方法。
Filter和Interceptor的調(diào)用鏈
// 以下是自定義攔截器TimeInterceptor的調(diào)用鏈
at com.nextyu.demo.web.interceptor.TimeInterceptor.preHandle(TimeInterceptor.java:31)
at org.springframework.web.servlet.HandlerExecutionChain.applyPreHandle(HandlerExecutionChain.java:133)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:962)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
// HttpServlet的實例是DispatcherServlet
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
// 以下是Tomcat的處理邏輯
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
// 以下是自定義Filter對象TimeFilter的調(diào)用鏈
at com.nextyu.demo.web.filter.TimeFilter.doFilter(TimeFilter.java:25)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
- locked <0x14f6> (a org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
參考
