/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package org.springframework.beans.factory.xml;import java.io.IOException;import java.net.URISyntaxException;import java.util.LinkedHashSet;import java.util.Set;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.w3c.dom.Document;import org.w3c.dom.Element;import org.w3c.dom.Node;import org.w3c.dom.NodeList;import org.springframework.beans.factory.BeanDefinitionStoreException;import org.springframework.beans.factory.config.BeanDefinitionHolder;import org.springframework.beans.factory.parsing.BeanComponentDefinition;import org.springframework.beans.factory.support.BeanDefinitionReaderUtils;import org.springframework.core.io.Resource;import org.springframework.core.io.support.ResourcePatternUtils;import org.springframework.lang.Nullable;import org.springframework.util.Assert;import org.springframework.util.ResourceUtils;import org.springframework.util.StringUtils;/** * Default implementation of the {@link BeanDefinitionDocumentReader} interface that * reads bean definitions according to the "spring-beans" DTD and XSD format * (Spring's default XML bean definition format). * * <p>The structure, elements, and attribute names of the required XML document * are hard-coded in this class. (Of course a transform could be run if necessary * to produce this format). {@code <beans>} does not need to be the root * element of the XML document: this class will parse all bean definition elements * in the XML file, regardless of the actual root element. * * @author Rod Johnson * @author Juergen Hoeller * @author Rob Harrop * @author Erik Wiersma * @since 18.12.2003 */public class DefaultBeanDefinitionDocumentReader implements BeanDefinitionDocumentReader { public static final String BEAN_ELEMENT = BeanDefinitionParserDelegate.BEAN_ELEMENT; public static final String NESTED_BEANS_ELEMENT = "beans"; public static final String ALIAS_ELEMENT = "alias"; public static final String NAME_ATTRIBUTE = "name"; public static final String ALIAS_ATTRIBUTE = "alias"; public static final String IMPORT_ELEMENT = "import"; public static final String RESOURCE_ATTRIBUTE = "resource"; public static final String PROFILE_ATTRIBUTE = "profile"; protected final Log logger = LogFactory.getLog(getClass()); @Nullable private XmlReaderContext readerContext; @Nullable private BeanDefinitionParserDelegate delegate; /** * This implementation parses bean definitions according to the "spring-beans" XSD * (or DTD, historically). * <p>Opens a DOM Document; then initializes the default settings * specified at the {@code <beans/>} level; then parses the contained bean definitions. */ @Override public void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) { this.readerContext = readerContext; doRegisterBeanDefinitions(doc.getDocumentElement()); } /** * Return the descriptor for the XML resource that this parser works on. */ protected final XmlReaderContext getReaderContext() { Assert.state(this.readerContext != null, "No XmlReaderContext available"); return this.readerContext; } /** * Invoke the {@link org.springframework.beans.factory.parsing.SourceExtractor} * to pull the source metadata from the supplied {@link Element}. */ @Nullable protected Object extractSource(Element ele) { return getReaderContext().extractSource(ele); } /** * Register each bean definition within the given root {@code <beans/>} element. */ @SuppressWarnings("deprecation") // for Environment.acceptsProfiles(String...) protected void doRegisterBeanDefinitions(Element root) { // Any nested <beans> elements will cause recursion in this method. In // order to propagate and preserve <beans> default-* attributes correctly, // keep track of the current (parent) delegate, which may be null. Create // the new (child) delegate with a reference to the parent for fallback purposes, // then ultimately reset this.delegate back to its original (parent) reference. // this behavior emulates a stack of delegates without actually necessitating one. BeanDefinitionParserDelegate parent = this.delegate; this.delegate = createDelegate(getReaderContext(), root, parent); if (this.delegate.isDefaultNamespace(root)) { String profileSpec = root.getAttribute(PROFILE_ATTRIBUTE); if (StringUtils.hasText(profileSpec)) { String[] specifiedProfiles = StringUtils.tokenizeToStringArray( profileSpec, BeanDefinitionParserDelegate.MULTI_VALUE_ATTRIBUTE_DELIMITERS); // We cannot use Profiles.of(...) since profile expressions are not supported // in XML config. See SPR-12458 for details. if (!getReaderContext().getEnvironment().acceptsProfiles(specifiedProfiles)) { if (logger.isDebugEnabled()) { logger.debug("Skipped XML bean definition file due to specified profiles [" + profileSpec + "] not matching: " + getReaderContext().getResource()); } return; } } } preProcessXml(root); parseBeanDefinitions(root, this.delegate); postProcessXml(root); this.delegate = parent; } protected BeanDefinitionParserDelegate createDelegate( XmlReaderContext readerContext, Element root, @Nullable BeanDefinitionParserDelegate parentDelegate) { BeanDefinitionParserDelegate delegate = new BeanDefinitionParserDelegate(readerContext); delegate.initDefaults(root, parentDelegate); return delegate; } /** * Parse the elements at the root level in the document: * "import", "alias", "bean". * @param root the DOM root element of the document */ protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) { if (delegate.isDefaultNamespace(root)) { NodeList nl = root.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (node instanceof Element) { Element ele = (Element) node; if (delegate.isDefaultNamespace(ele)) { parseDefaultElement(ele, delegate); } else { delegate.parseCustomElement(ele); } } } } else { delegate.parseCustomElement(root); } } private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) { if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) { importBeanDefinitionResource(ele); } else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) { processAliasRegistration(ele); } else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) { processBeanDefinition(ele, delegate); } else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) { // recurse doRegisterBeanDefinitions(ele); } } /** * Parse an "import" element and load the bean definitions * from the given resource into the bean factory. */ protected void importBeanDefinitionResource(Element ele) { String location = ele.getAttribute(RESOURCE_ATTRIBUTE); if (!StringUtils.hasText(location)) { getReaderContext().error("Resource location must not be empty", ele); return; } // Resolve system properties: e.g. "${user.dir}" location = getReaderContext().getEnvironment().resolveRequiredPlaceholders(location); Set<Resource> actualResources = new LinkedHashSet<>(4); // Discover whether the location is an absolute or relative URI boolean absoluteLocation = false; try { absoluteLocation = ResourcePatternUtils.isUrl(location) || ResourceUtils.toURI(location).isAbsolute(); } catch (URISyntaxException ex) { // cannot convert to an URI, considering the location relative // unless it is the well-known Spring prefix "classpath*:" } // Absolute or relative? if (absoluteLocation) { try { int importCount = getReaderContext().getReader().loadBeanDefinitions(location, actualResources); if (logger.isTraceEnabled()) { logger.trace("Imported " + importCount + " bean definitions from URL location [" + location + "]"); } } catch (BeanDefinitionStoreException ex) { getReaderContext().error( "Failed to import bean definitions from URL location [" + location + "]", ele, ex); } } else { // No URL -> considering resource location as relative to the current file. try { int importCount; Resource relativeResource = getReaderContext().getResource().createRelative(location); if (relativeResource.exists()) { importCount = getReaderContext().getReader().loadBeanDefinitions(relativeResource); actualResources.add(relativeResource); } else { String baseLocation = getReaderContext().getResource().getURL().toString(); importCount = getReaderContext().getReader().loadBeanDefinitions( StringUtils.applyRelativePath(baseLocation, location), actualResources); } if (logger.isTraceEnabled()) { logger.trace("Imported " + importCount + " bean definitions from relative location [" + location + "]"); } } catch (IOException ex) { getReaderContext().error("Failed to resolve current resource location", ele, ex); } catch (BeanDefinitionStoreException ex) { getReaderContext().error( "Failed to import bean definitions from relative location [" + location + "]", ele, ex); } } Resource[] actResArray = actualResources.toArray(new Resource[0]); getReaderContext().fireImportProcessed(location, actResArray, extractSource(ele)); } /** * Process the given alias element, registering the alias with the registry. */ protected void processAliasRegistration(Element ele) { String name = ele.getAttribute(NAME_ATTRIBUTE); String alias = ele.getAttribute(ALIAS_ATTRIBUTE); boolean valid = true; if (!StringUtils.hasText(name)) { getReaderContext().error("Name must not be empty", ele); valid = false; } if (!StringUtils.hasText(alias)) { getReaderContext().error("Alias must not be empty", ele); valid = false; } if (valid) { try { getReaderContext().getRegistry().registerAlias(name, alias); } catch (Exception ex) { getReaderContext().error("Failed to register alias '" + alias + "' for bean with name '" + name + "'", ele, ex); }