spring读取xml配置文件（二）

一、当spring解析完配置文件名的占位符后，就开始refresh容器

 @Override
     public void refresh() throws BeansException, IllegalStateException {
         synchronized (this.startupShutdownMonitor) {
             // Prepare this context for refreshing.
               //设置了启动时间，激活状态设为true，初始化一些propertySource
               //初始化的时候啥都没做，是个空方法。设置状态为开启
             prepareRefresh();

             // Tell the subclass to refresh the internal bean factory.
               //这个方法内部刷新了BeanFactory，如果BeanFactory存在，那么先销毁，然后
               //重新创建新的BeanFactory
             ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

             // Prepare the bean factory for use in this context.
             prepareBeanFactory(beanFactory);

             try {
                 // Allows post-processing of the bean factory in context subclasses.
                 postProcessBeanFactory(beanFactory);

                 // Invoke factory processors registered as beans in the context.
                 invokeBeanFactoryPostProcessors(beanFactory);

                 // Register bean processors that intercept bean creation.
                 registerBeanPostProcessors(beanFactory);

                 // Initialize message source for this context.
                 initMessageSource();

                 // Initialize event multicaster for this context.
                 initApplicationEventMulticaster();

                 // Initialize other special beans in specific context subclasses.
                 onRefresh();

                 // Check for listener beans and register them.
                 registerListeners();

                 // Instantiate all remaining (non-lazy-init) singletons.
                 finishBeanFactoryInitialization(beanFactory);

                 // Last step: publish corresponding event.
                 finishRefresh();
             }

             catch (BeansException ex) {
                 if (logger.isWarnEnabled()) {
                     logger.warn("Exception encountered during context initialization - " +
                             "cancelling refresh attempt: " + ex);
                 }

                 // Destroy already created singletons to avoid dangling resources.
                 destroyBeans();

                 // Reset 'active' flag.
                 cancelRefresh(ex);

                 // Propagate exception to caller.
                 throw ex;
             }

             finally {
                 // Reset common introspection caches in Spring's core, since we
                 // might not ever need metadata for singleton beans anymore...
                 resetCommonCaches();
             }
         }
     }

第7行设置了容器启动的时间，容器的状态被修改为false，表示已经启动，并且初始化PropertySource,不过初始化PropertySource内部的代码是空的，什么都没做。

第12行代码是对BeanFactory进行刷新，它调用了refreBeanFactory方法它的代码如下

 @Override
     protected final void refreshBeanFactory() throws BeansException {
         if (hasBeanFactory()) {
             destroyBeans();
             closeBeanFactory();
         }
         try {
             DefaultListableBeanFactory beanFactory = createBeanFactory();
             beanFactory.setSerializationId(getId());
             customizeBeanFactory(beanFactory);
             loadBeanDefinitions(beanFactory);
             synchronized (this.beanFactoryMonitor) {
                 this.beanFactory = beanFactory;
             }
         }
         catch (IOException ex) {
             throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
         }
     }

首先判断这个Bean工厂是否已经存在，如果存在了就直接销毁，重新创建一个DefaultListableBeanFactory工厂，

这个工厂在创建的时候初始化了许多的容器字段，如是否可以在覆盖同名不同定义的bean定义，beanName->beanDefinition容器and so on.

    /** Optional id for this factory, for serialization purposes */
    private String serializationId;

    /** Whether to allow re-registration of a different definition with the same name */
    private boolean allowBeanDefinitionOverriding = true;

    /** Whether to allow eager class loading even for lazy-init beans */
    private boolean allowEagerClassLoading = true;

    /** Optional OrderComparator for dependency Lists and arrays */
    private Comparator<Object> dependencyComparator;

    /** Resolver to use for checking if a bean definition is an autowire candidate */
    private AutowireCandidateResolver autowireCandidateResolver = new SimpleAutowireCandidateResolver();

    /** Map from dependency type to corresponding autowired value */
    private final Map<Class<?>, Object> resolvableDependencies = new ConcurrentHashMap<Class<?>, Object>(16);

    /** Map of bean definition objects, keyed by bean name */
    private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(256);

    /** Map of singleton and non-singleton bean names, keyed by dependency type */
    private final Map<Class<?>, String[]> allBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64);

    /** Map of singleton-only bean names, keyed by dependency type */
    private final Map<Class<?>, String[]> singletonBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64);

    /** List of bean definition names, in registration order */
    private volatile List<String> beanDefinitionNames = new ArrayList<String>(256);

    /** List of names of manually registered singletons, in registration order */
    private volatile Set<String> manualSingletonNames = new LinkedHashSet<String>(16);

并且给这个Bean工厂设置序列化的id，这个序列化ID是工厂类的全限定名+@+这个工厂实例的hashcode

第10行customizeBeanFactory方法是在AbstractRefreshableApplicationContext类中定义的它的代码如下

if (this.allowBeanDefinitionOverriding != null) {
beanFactory.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
}
if (this.allowCircularReferences != null) {
beanFactory.setAllowCircularReferences(this.allowCircularReferences);
}

如果这个应用上下文没有定义能否bean定义覆盖和循环依赖这两个属性就使用默认值，默认值都是为true

第11行代码loadBeanDefinitions(beanFactory)创建了的XmlBeanDefinitionReader实例，它的继承结构，继承自抽象的bean定义阅读器

这个方法内部的代码如下

 @Override
     protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException {
         // Create a new XmlBeanDefinitionReader for the given BeanFactory.
         XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);

         // Configure the bean definition reader with this context's
         // resource loading environment.
         beanDefinitionReader.setEnvironment(this.getEnvironment());
         beanDefinitionReader.setResourceLoader(this);
         beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));

         // Allow a subclass to provide custom initialization of the reader,
         // then proceed with actually loading the bean definitions.
         initBeanDefinitionReader(beanDefinitionReader);
         loadBeanDefinitions(beanDefinitionReader);
     }

第8行将ClasspathXmlApplicationContext中的环境变量设置到新创建的bean定义阅读器，把ClasspathXmlApplicationContext(它继承了ResourceLoader接口)资源加载器设置进去，设置实体解析器，这个解析器，实现的接口时EntityResolver，它的实现类有好多，这里设置的是一个SAX解析器，用于读取xml，这里绕来绕去的，看下ClasspathXmlApplicationContext的继承结构.

第14行初始化bean定义阅读器，它主要是对这个xml阅读器进行了验证模式的设置，是自动验证还是不验证

第15行传入xml阅读器，准备读取xml，这个方法的代码如下

 protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws BeansException, IOException {
         Resource[] configResources = getConfigResources();
         if (configResources != null) {
             reader.loadBeanDefinitions(configResources);
         }
         String[] configLocations = getConfigLocations();
         if (configLocations != null) {
             reader.loadBeanDefinitions(configLocations);
         }
     }

第8行将配置文件传入阅读器，loadBeanDefinitions方法的代码如下

 public int loadBeanDefinitions(String location, Set<Resource> actualResources) throws BeanDefinitionStoreException {
         ResourceLoader resourceLoader = getResourceLoader();
         if (resourceLoader == null) {
             throw new BeanDefinitionStoreException(
                     "Cannot import bean definitions from location [" + location + "]: no ResourceLoader available");
         }

         if (resourceLoader instanceof ResourcePatternResolver) {
             // Resource pattern matching available.
             try {
                 Resource[] resources = ((ResourcePatternResolver) resourceLoader).getResources(location);
                 int loadCount = loadBeanDefinitions(resources);
                 if (actualResources != null) {
                     for (Resource resource : resources) {
                         actualResources.add(resource);
                     }
                 }
                 if (logger.isDebugEnabled()) {
                     logger.debug("Loaded " + loadCount + " bean definitions from location pattern [" + location + "]");
                 }
                 return loadCount;
             }
             catch (IOException ex) {
                 throw new BeanDefinitionStoreException(
                         "Could not resolve bean definition resource pattern [" + location + "]", ex);
             }
         }
         else {
             // Can only load single resources by absolute URL.
             Resource resource = resourceLoader.getResource(location);
             int loadCount = loadBeanDefinitions(resource);
             if (actualResources != null) {
                 actualResources.add(resource);
             }
             if (logger.isDebugEnabled()) {
                 logger.debug("Loaded " + loadCount + " bean definitions from location [" + location + "]");
             }
             return loadCount;
         }
     }

第2行这个resourceLoader 是之前创建XmlBeanDefinitionReader这个xml阅读器传进来的ClasspathXmlApplictionContext,这个类，在上面的图已经告诉了我们它是ResourceLoader的子类

第11行开始进入资源的解析，也就是对配置文件的路径找到所有的xml，并与之匹配，详细情况继续往下

 @Override
     public Resource[] getResources(String locationPattern) throws IOException {
         return this.resourcePatternResolver.getResources(locationPattern);
     }

第3行的resourcePatternResolver是一个PathMatchingResourcePatternResolver的实例，这个实例在创建ClasspathXmlApplicationContext的时候调用父类AbstractApplicationContext时被创建。这些路径匹配器的继承结构为

继续进入PathMatchingResourcePatternResolver的getResources方法

 @Override
     public Resource[] getResources(String locationPattern) throws IOException {
         Assert.notNull(locationPattern, "Location pattern must not be null");
         if (locationPattern.startsWith(CLASSPATH_ALL_URL_PREFIX)) {
             // a class path resource (multiple resources for same name possible)
             if (getPathMatcher().isPattern(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()))) {
                 // a class path resource pattern
                 return findPathMatchingResources(locationPattern);
             }
             else {
                 // all class path resources with the given name
                 return findAllClassPathResources(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()));
             }
         }
         else {
             // Only look for a pattern after a prefix here
             // (to not get fooled by a pattern symbol in a strange prefix).
             int prefixEnd = locationPattern.indexOf(":") + 1;
             if (getPathMatcher().isPattern(locationPattern.substring(prefixEnd))) {
                 // a file pattern
                 return findPathMatchingResources(locationPattern);
             }
             else {
                 // a single resource with the given name
                 return new Resource[] {getResourceLoader().getResource(locationPattern)};
             }
         }
     }

第4行中的CLASSPATH_ALL_URL_PREFIX的值为classpath*：，这里是判断这个配置文件是不是以classpath*：开头的，如果不是那么就跳到第18行，取得：后面的字符串，如：classpath：spring/spring-*.xml或者spring/spring-*.xml最终都会得到spring/spring-*.xml这个字符串。如果这个字符串不含通配符，那么直接包装成resource数组返回。

第6行getPathMatcher()获得一个AntPathMatcher实例调用isPattern判断这个配置文件是不是使用了*或者？通配符的，代码如下。

@Override
    public boolean isPattern(String path) {
        return (path.indexOf('*') != -1 || path.indexOf('?') != -1);
     }

如果有通配符就执行第8行，如果没有就执行第12行，

第12行的findAllClassPathResources方法，获取各加载器的类路径下的所有名字匹配的配置文件，假如配置文件叫做classpath*：spring/spring-context.xml,那么它先从父加载器中找。

它调用的classLoader的getResoures方法，代码如下：

 protected Set<Resource> doFindAllClassPathResources(String path) throws IOException {
         Set<Resource> result = new LinkedHashSet<Resource>(16);
         ClassLoader cl = getClassLoader();
         Enumeration<URL> resourceUrls = (cl != null ? cl.getResources(path) : ClassLoader.getSystemResources(path));
         while (resourceUrls.hasMoreElements()) {
             URL url = resourceUrls.nextElement();
             result.add(convertClassLoaderURL(url));
         }
         if ("".equals(path)) {
             // The above result is likely to be incomplete, i.e. only containing file system references.
             // We need to have pointers to each of the jar files on the classpath as well...
             addAllClassLoaderJarRoots(cl, result);
         }
         return result;
     }

第12行addAllClassLoaderJarRoots方法是在只写了classpath*：前缀，却没有指定配置文件的情况下调用，它还会去寻找jar文件，然后包装成resource返回

第4行就调用了getResources方法，看看getResources方法的代码，parent值得是父加载器。

 public Enumeration<URL> getResources(String name) throws IOException {
         @SuppressWarnings("unchecked")
         Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2];
         if (parent != null) {
             tmp[0] = parent.getResources(name);
         } else {
             tmp[0] = getBootstrapResources(name);
         }
         tmp[1] = findResources(name);

         return new CompoundEnumeration<>(tmp);
     }

如果配置文件的路径里有通配符，那么会进入findPathMatchingResources方法

 protected Resource[] findPathMatchingResources(String locationPattern) throws IOException {
         String rootDirPath = determineRootDir(locationPattern);
         String subPattern = locationPattern.substring(rootDirPath.length());
         Resource[] rootDirResources = getResources(rootDirPath);
         Set<Resource> result = new LinkedHashSet<Resource>(16);
         for (Resource rootDirResource : rootDirResources) {
             rootDirResource = resolveRootDirResource(rootDirResource);
 8             if (rootDirResource.getURL().getProtocol().startsWith(ResourceUtils.URL_PROTOCOL_VFS)) {
                 result.addAll(VfsResourceMatchingDelegate.findMatchingResources(rootDirResource, subPattern, getPathMatcher()));
             }
             else if (isJarResource(rootDirResource)) {
                 result.addAll(doFindPathMatchingJarResources(rootDirResource, subPattern));
             }
             else {
                 result.addAll(doFindPathMatchingFileResources(rootDirResource, subPattern));
             }
         }
         if (logger.isDebugEnabled()) {
             logger.debug("Resolved location pattern [" + locationPattern + "] to resources " + result);
         }
         return result.toArray(new Resource[result.size()]);
     }

第二行的determineRootDir方法的代码如下，仍然要判断是否是通配符的配置文件，如果是那么寻找最后一个/，如果找到就截取这个/前面的一段字符串，如：classpath*：spring/spring-*context.xml,就会被获取到classpath*:spring/这一段，如果没有/就取到classpath*：

protected String determineRootDir(String location) {
        int prefixEnd = location.indexOf(":") + 1;
        int rootDirEnd = location.length();
        while (rootDirEnd > prefixEnd && getPathMatcher().isPattern(location.substring(prefixEnd, rootDirEnd))) {
            rootDirEnd = location.lastIndexOf('/', rootDirEnd - 2) + 1;
        }
        if (rootDirEnd == 0) {
            rootDirEnd = prefixEnd;
        }
        return location.substring(0, rootDirEnd);
    }

第3行表示截取通配符那一段，如classpath*：spring/spring-*.xml,会获取到spring-*.xml

第4行是从rootDir下找，如classpath*:spring/下找所有的配置文件，这段代码上面分析过，不过可以长话短说的再分析一遍，假设当前的locationPattern就是classpath*:spring/

 @Override
     public Resource[] getResources(String locationPattern) throws IOException {
         Assert.notNull(locationPattern, "Location pattern must not be null");
         if (locationPattern.startsWith(CLASSPATH_ALL_URL_PREFIX)) {
             // a class path resource (multiple resources for same name possible)
             if (getPathMatcher().isPattern(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()))) {
                 // a class path resource pattern
                 return findPathMatchingResources(locationPattern);
             }
             else {
                 // all class path resources with the given name
                 return findAllClassPathResources(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()));
             }
         }
         else {
             // Only look for a pattern after a prefix here
             // (to not get fooled by a pattern symbol in a strange prefix).
             int prefixEnd = locationPattern.indexOf(":") + 1;
             if (getPathMatcher().isPattern(locationPattern.substring(prefixEnd))) {
                 // a file pattern
                 return findPathMatchingResources(locationPattern);
             }
             else {
                 // a single resource with the given name
                 return new Resource[] {getResourceLoader().getResource(locationPattern)};
             }
         }
     }

先判断是否是以classpath*:,如果是，那再判断带不带通配符，如果不带，直接调用findAllClassPathResources方法，调用所有的加载器，先从父类开始，在所有的加载器的类路径包装成resource。

第6行循环根路径开始寻找配置文件了

第7行对路径进行解析，判断是否为OSGI类型的路径

第8行，判断是不是vfs协议的文件资源路径

第11行判断是不是jar类型的资源路径

第15行开始查找了，只要看到do开头的方法，基本就是开始真正开始办事了

 protected Set<Resource> doFindPathMatchingFileResources(Resource rootDirResource, String subPattern)
             throws IOException {

         File rootDir;
         try {
             rootDir = rootDirResource.getFile().getAbsoluteFile();
         }
         catch (IOException ex) {
             if (logger.isWarnEnabled()) {
                 logger.warn("Cannot search for matching files underneath " + rootDirResource +
                         " because it does not correspond to a directory in the file system", ex);
             }
             return Collections.emptySet();
         }
         return doFindMatchingFileSystemResources(rootDir, subPattern);
     }

第6行拿到这个根路径的绝对地址，最后再第15行调用doFindMatchingFileSystemResources,传入了俩个参数，一个是根路径，另一个就含通配符的那个字符串

 protected Set<Resource> doFindMatchingFileSystemResources(File rootDir, String subPattern) throws IOException {
         if (logger.isDebugEnabled()) {
             logger.debug("Looking for matching resources in directory tree [" + rootDir.getPath() + "]");
         }
         Set<File> matchingFiles = retrieveMatchingFiles(rootDir, subPattern);
         Set<Resource> result = new LinkedHashSet<Resource>(matchingFiles.size());
         for (File file : matchingFiles) {
             result.add(new FileSystemResource(file));
         }
         return result;
     }

直接看第5行的retrieveMatchingFiles方法代码

 protected Set<File> retrieveMatchingFiles(File rootDir, String pattern) throws IOException {
         if (!rootDir.exists()) {
             // Silently skip non-existing directories.
             if (logger.isDebugEnabled()) {
                 logger.debug("Skipping [" + rootDir.getAbsolutePath() + "] because it does not exist");
             }
             return Collections.emptySet();
         }
         if (!rootDir.isDirectory()) {
             // Complain louder if it exists but is no directory.
             if (logger.isWarnEnabled()) {
                 logger.warn("Skipping [" + rootDir.getAbsolutePath() + "] because it does not denote a directory");
             }
             return Collections.emptySet();
         }
         if (!rootDir.canRead()) {
             if (logger.isWarnEnabled()) {
                 logger.warn("Cannot search for matching files underneath directory [" + rootDir.getAbsolutePath() +
                         "] because the application is not allowed to read the directory");
             }
             return Collections.emptySet();
         }
         String fullPattern = StringUtils.replace(rootDir.getAbsolutePath(), File.separator, "/");
         if (!pattern.startsWith("/")) {
             fullPattern += "/";
         }
         fullPattern = fullPattern + StringUtils.replace(pattern, File.separator, "/");
         Set<File> result = new LinkedHashSet<File>(8);
         doRetrieveMatchingFiles(fullPattern, rootDir, result);
         return result;
     }

如果根路径不存在或者是个目录或者是不可读的，那么直接返回一个空的集合

第23行，将\\替换成/

第28行，将绝对根路径和通配符字符串连接起来

第29行，我们又看到do开头的方法了，好高兴，进去看看，fullPattern 是全路径，dir是根路径，result是用来装资源的

 protected void doRetrieveMatchingFiles(String fullPattern, File dir, Set<File> result) throws IOException {
         if (logger.isDebugEnabled()) {
             logger.debug("Searching directory [" + dir.getAbsolutePath() +
                     "] for files matching pattern [" + fullPattern + "]");
         }
         File[] dirContents = dir.listFiles();
         if (dirContents == null) {
             if (logger.isWarnEnabled()) {
                 logger.warn("Could not retrieve contents of directory [" + dir.getAbsolutePath() + "]");
             }
             return;
         }
         for (File content : dirContents) {
             String currPath = StringUtils.replace(content.getAbsolutePath(), File.separator, "/");
             if (content.isDirectory() && getPathMatcher().matchStart(fullPattern, currPath + "/")) {
                 if (!content.canRead()) {
                     if (logger.isDebugEnabled()) {
                         logger.debug("Skipping subdirectory [" + dir.getAbsolutePath() +
                                 "] because the application is not allowed to read the directory");
                     }
                 }
                 else {
                     doRetrieveMatchingFiles(fullPattern, content, result);
                 }
             }
             if (getPathMatcher().match(fullPattern, currPath)) {
                 result.add(content);
             }
         }
     }

第6行得到了根路径下的所有文件，循环这些file，如果是目录，那么继续匹配，调用matchStart方法，这个方法里面又调用了doMatch方法

 protected boolean doMatch(String pattern, String path, boolean fullMatch, Map<String, String> uriTemplateVariables) {
         if (path.startsWith(this.pathSeparator) != pattern.startsWith(this.pathSeparator)) {
             return false;
         }

         String[] pattDirs = tokenizePattern(pattern);
         String[] pathDirs = tokenizePath(path);

         int pattIdxStart = 0;
         int pattIdxEnd = pattDirs.length - 1;
         int pathIdxStart = 0;
         int pathIdxEnd = pathDirs.length - 1;

         // Match all elements up to the first **
         while (pattIdxStart <= pattIdxEnd && pathIdxStart <= pathIdxEnd) {
             String pattDir = pattDirs[pattIdxStart];
             if ("**".equals(pattDir)) {
                 break;
             }
             if (!matchStrings(pattDir, pathDirs[pathIdxStart], uriTemplateVariables)) {
                 return false;
             }
             pattIdxStart++;
             pathIdxStart++;
         }

         if (pathIdxStart > pathIdxEnd) {
             // Path is exhausted, only match if rest of pattern is * or **'s
             if (pattIdxStart > pattIdxEnd) {
                 return (pattern.endsWith(this.pathSeparator) ? path.endsWith(this.pathSeparator) :
                         !path.endsWith(this.pathSeparator));
             }
             if (!fullMatch) {
                 return true;
             }
             if (pattIdxStart == pattIdxEnd && pattDirs[pattIdxStart].equals("*") && path.endsWith(this.pathSeparator)) {
                 return true;
             }
             for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
                 if (!pattDirs[i].equals("**")) {
                     return false;
                 }
             }
             return true;
         }
         else if (pattIdxStart > pattIdxEnd) {
             // String not exhausted, but pattern is. Failure.
             return false;
         }
         else if (!fullMatch && "**".equals(pattDirs[pattIdxStart])) {
             // Path start definitely matches due to "**" part in pattern.
             return true;
         }

         // up to last '**'
         while (pattIdxStart <= pattIdxEnd && pathIdxStart <= pathIdxEnd) {
             String pattDir = pattDirs[pattIdxEnd];
             if (pattDir.equals("**")) {
                 break;
             }
             if (!matchStrings(pattDir, pathDirs[pathIdxEnd], uriTemplateVariables)) {
                 return false;
             }
             pattIdxEnd--;
             pathIdxEnd--;
         }
         if (pathIdxStart > pathIdxEnd) {
             // String is exhausted
             for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
                 if (!pattDirs[i].equals("**")) {
                     return false;
                 }
             }
             return true;
         }

         while (pattIdxStart != pattIdxEnd && pathIdxStart <= pathIdxEnd) {
             int patIdxTmp = -1;
             for (int i = pattIdxStart + 1; i <= pattIdxEnd; i++) {
                 if (pattDirs[i].equals("**")) {
                     patIdxTmp = i;
                     break;
                 }
             }
             if (patIdxTmp == pattIdxStart + 1) {
                 // '**/**' situation, so skip one
                 pattIdxStart++;
                 continue;
             }
             // Find the pattern between padIdxStart & padIdxTmp in str between
             // strIdxStart & strIdxEnd
             int patLength = (patIdxTmp - pattIdxStart - 1);
             int strLength = (pathIdxEnd - pathIdxStart + 1);
             int foundIdx = -1;

             strLoop:
             for (int i = 0; i <= strLength - patLength; i++) {
                 for (int j = 0; j < patLength; j++) {
                     String subPat = pattDirs[pattIdxStart + j + 1];
                     String subStr = pathDirs[pathIdxStart + i + j];
                     if (!matchStrings(subPat, subStr, uriTemplateVariables)) {
                         continue strLoop;
                     }
                 }
                 foundIdx = pathIdxStart + i;
                 break;
             }

             if (foundIdx == -1) {
                 return false;
             }

             pattIdxStart = patIdxTmp;
             pathIdxStart = foundIdx + patLength;
         }

         for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
             if (!pattDirs[i].equals("**")) {
                 return false;
             }
         }

         return true;
     }

第6,7行将路径按照/进行分割成字符串数组

第17行，如果发现通配符出现**，那么退出循环，跳到第50行判断是不是全匹配，如果不是全匹配那么就返回true

如果fullMatcher为true，那么就跳到56行，从后往前匹配，如果中间出现任何不匹配的就返回false，如果都匹配，那么会匹配到**，那么又退出循环，跳到第117行，此时可以确定返回true了

如果没有通配符的情况下，并且都验证通过，那么会进入第21行进行验证，得看看匹配路径是否是目录，如果是目录那么就匹配失败。

第61行，这里会把通配符*和？替换成正则表达式，替换的逻辑代码如下：

 public AntPathStringMatcher(String pattern, boolean caseSensitive) {
             StringBuilder patternBuilder = new StringBuilder();
             Matcher matcher = GLOB_PATTERN.matcher(pattern);
             int end = 0;
             while (matcher.find()) {
                 patternBuilder.append(quote(pattern, end, matcher.start()));
                 String match = matcher.group();
                 if ("?".equals(match)) {
                     patternBuilder.append('.');
                 }
                 else if ("*".equals(match)) {
                     patternBuilder.append(".*");
                 }
                 else if (match.startsWith("{") && match.endsWith("}")) {
                     int colonIdx = match.indexOf(':');
                     if (colonIdx == -1) {
                         patternBuilder.append(DEFAULT_VARIABLE_PATTERN);
                         this.variableNames.add(matcher.group(1));
                     }
                     else {
                         String variablePattern = match.substring(colonIdx + 1, match.length() - 1);
                         patternBuilder.append('(');
                         patternBuilder.append(variablePattern);
                         patternBuilder.append(')');
                         String variableName = match.substring(1, colonIdx);
                         this.variableNames.add(variableName);
                     }
                 }
                 end = matcher.end();
             }
             patternBuilder.append(quote(pattern, end, pattern.length()));
             this.pattern = (caseSensitive ? Pattern.compile(patternBuilder.toString()) :
                     Pattern.compile(patternBuilder.toString(), Pattern.CASE_INSENSITIVE));
         }

第6行将截取从0开始到找到第一个匹配的子字符串的位置的字符串，并加上单引号，如：spring-*.xml 会截取到'spring-'这样的字符串

第七行获得匹配的字符串，这里是*

下面进行了判断，如果是*，那么就替换成.*追加到字符串后面

找到匹配的配置文件后，就添加到一个set集合中

最后我们再回到doFindMatchingFileSystemResources方法

 protected Set<Resource> doFindMatchingFileSystemResources(File rootDir, String subPattern) throws IOException {
         if (logger.isDebugEnabled()) {
             logger.debug("Looking for matching resources in directory tree [" + rootDir.getPath() + "]");
         }
         Set<File> matchingFiles = retrieveMatchingFiles(rootDir, subPattern);
         Set<Resource> result = new LinkedHashSet<Resource>(matchingFiles.size());
         for (File file : matchingFiles) {
             result.add(new FileSystemResource(file));
         }
         return result;
     }

第8表示这些文件都被打包成resource加到set集合里，最后一只返回到AbstractBeanDefinition类的loadBeanDefinitions方法

 public int loadBeanDefinitions(String location, Set<Resource> actualResources) throws BeanDefinitionStoreException {
         ResourceLoader resourceLoader = getResourceLoader();
         if (resourceLoader == null) {
             throw new BeanDefinitionStoreException(
                     "Cannot import bean definitions from location [" + location + "]: no ResourceLoader available");
         }

         if (resourceLoader instanceof ResourcePatternResolver) {
             // Resource pattern matching available.
             try {
                 Resource[] resources = ((ResourcePatternResolver) resourceLoader).getResources(location);
                 int loadCount = loadBeanDefinitions(resources);
                 if (actualResources != null) {
                     for (Resource resource : resources) {
                         actualResources.add(resource);
                     }
                 }
                 if (logger.isDebugEnabled()) {
                     logger.debug("Loaded " + loadCount + " bean definitions from location pattern [" + location + "]");
                 }
                 return loadCount;
             }
             catch (IOException ex) {
                 throw new BeanDefinitionStoreException(
                         "Could not resolve bean definition resource pattern [" + location + "]", ex);
             }
         }
         else {
             // Can only load single resources by absolute URL.
             Resource resource = resourceLoader.getResource(location);
             int loadCount = loadBeanDefinitions(resource);
             if (actualResources != null) {
                 actualResources.add(resource);
             }
             if (logger.isDebugEnabled()) {
                 logger.debug("Loaded " + loadCount + " bean definitions from location [" + location + "]");
             }
             return loadCount;
         }
     }

第12行，调用了重载方法loadBeanDefinitions（Resource[]）,方法调用一直进入到了XmlBeanDefinitionReader类中的loadBeanDefinitions方法

     public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {
         Assert.notNull(encodedResource, "EncodedResource must not be null");
         if (logger.isInfoEnabled()) {
             logger.info("Loading XML bean definitions from " + encodedResource.getResource());
         }

         Set<EncodedResource> currentResources = this.resourcesCurrentlyBeingLoaded.get();
         if (currentResources == null) {
             currentResources = new HashSet<EncodedResource>(4);
             this.resourcesCurrentlyBeingLoaded.set(currentResources);
         }
         if (!currentResources.add(encodedResource)) {
             throw new BeanDefinitionStoreException(
                     "Detected cyclic loading of " + encodedResource + " - check your import definitions!");
         }
         try {
             InputStream inputStream = encodedResource.getResource().getInputStream();
             try {
                 InputSource inputSource = new InputSource(inputStream);
                 if (encodedResource.getEncoding() != null) {
                     inputSource.setEncoding(encodedResource.getEncoding());
                 }
                 return doLoadBeanDefinitions(inputSource, encodedResource.getResource());
             }
             finally {
                 inputStream.close();
             }
         }
         catch (IOException ex) {
             throw new BeanDefinitionStoreException(
                     "IOException parsing XML document from " + encodedResource.getResource(), ex);
         }
         finally {
             currentResources.remove(encodedResource);
             if (currentResources.isEmpty()) {
                 this.resourcesCurrentlyBeingLoaded.remove();
             }
         }
     }

第17行，拿到这个配置文件的输入流，并包装成InputSource，这个时候我们又看到了do开头的方法doLoadBeanDefinitions，它的代码为

 try {
             Document doc = doLoadDocument(inputSource, resource);
             return registerBeanDefinitions(doc, resource);
         }

看到第二行，这个配置文件被加载成了Document对象，在进入doLoadDocument方法

 protected Document doLoadDocument(InputSource inputSource, Resource resource) throws Exception {
         return this.documentLoader.loadDocument(inputSource, getEntityResolver(), this.errorHandler,
                 getValidationModeForResource(resource), isNamespaceAware());
     }

看到第3行，获得验证模式，它是根据这个xml的是否以DOCTYPE开头来确定时dtd验证还是xsd验证

 public int detectValidationMode(InputStream inputStream) throws IOException {
         // Peek into the file to look for DOCTYPE.
         BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
         try {
             boolean isDtdValidated = false;
             String content;
             while ((content = reader.readLine()) != null) {
                 content = consumeCommentTokens(content);
                 if (this.inComment || !StringUtils.hasText(content)) {
                     continue;
                 }
                 if (hasDoctype(content)) {
                     isDtdValidated = true;
                     break;
                 }
                 if (hasOpeningTag(content)) {
                     // End of meaningful data...
                     break;
                 }
             }
             return (isDtdValidated ? VALIDATION_DTD : VALIDATION_XSD);
         }
         catch (CharConversionException ex) {
             // Choked on some character encoding...
             // Leave the decision up to the caller.
             return VALIDATION_AUTO;
         }
         finally {
             reader.close();
         }
     }

第12行的hasDoctype方法

private boolean hasDoctype(String content) {
        return content.contains(DOCTYPE);
    }

DOCTYPE的值就是DOCTYPE字符串

看看document是怎么创建的

 @Override
     public Document loadDocument(InputSource inputSource, EntityResolver entityResolver,
             ErrorHandler errorHandler, int validationMode, boolean namespaceAware) throws Exception {

         DocumentBuilderFactory factory = createDocumentBuilderFactory(validationMode, namespaceAware);
         if (logger.isDebugEnabled()) {
             logger.debug("Using JAXP provider [" + factory.getClass().getName() + "]");
         }
         DocumentBuilder builder = createDocumentBuilder(factory, entityResolver, errorHandler);
         return builder.parse(inputSource);
     }

首先在第5行创建了一个文档构建工厂，然后通过工厂创建构建者，最后用构建者解析输入资源，返回一个文档对象，这些类是JDK中javax.xml.parses包下的类，我们学习解析xml的时候已经使用过了，这里就不再往里面跑了。这样配置文件的读取工作就搞定了，接下来的就是解析配置文件了。

方法调用的序列图