spring源码（6）bean标签其他子标签的解析
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spring bean子标签 loopup-method、replaced-method基本用法参见：http://blog.csdn.net/disiwei1012/article/details/70495940
本节介绍bean标签的其他子标签的解析
1.子元素meta解析
<bean id="test" class="com.demo.test"> <meta key="testStr" value="aaa"/></bean>//解析子元素metaparseMetaElements(ele, bd);public void parseMetaElements(Element ele, BeanMetadataAttributeAccessor attributeAccessor) { NodeList nl = ele.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, META_ELEMENT)) { Element metaElement = (Element) node; //key属性 String key = metaElement.getAttribute(KEY_ATTRIBUTE); //value属性 String value = metaElement.getAttribute(VALUE_ATTRIBUTE); //构造BeanMetadataAttribute BeanMetadataAttribute attribute = new BeanMetadataAttribute(key, value); attribute.setSource(extractSource(metaElement)); attributeAccessor.addMetadataAttribute(attribute); } }}2.子元素loopup-method解析
<bean id="test" class="com.demo.test"> <lookup-method name="getBean" bean="teacher"/></bean><bean id="teacher" class="com.test.teacher"/>//解析子元素loopup-methodparseLookupOverrideSubElements(ele, bd.getMethodOverrides());public void parseLookupOverrideSubElements(Element beanEle, MethodOverrides overrides) { NodeList nl = beanEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, LOOKUP_METHOD_ELEMENT)) { Element ele = (Element) node; //属性name String methodName = ele.getAttribute(NAME_ATTRIBUTE); //属性bean String beanRef = ele.getAttribute(BEAN_ELEMENT); LookupOverride override = new LookupOverride(methodName, beanRef); override.setSource(extractSource(ele)); overrides.addOverride(override); } }}3.子元素replaced-method解析
<bean id="test" class="com.demo.test"> <replaced-method name="changeMe" replacer="replacer"/></bean><bean id="replacer" class="com.test.replacer"/>//解析子元素replaced-methodparseReplacedMethodSubElements(ele, bd.getMethodOverrides());public void parseReplacedMethodSubElements(Element beanEle, MethodOverrides overrides) { NodeList nl = beanEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, REPLACED_METHOD_ELEMENT)) { Element replacedMethodEle = (Element) node; //name属性 String name = replacedMethodEle.getAttribute(NAME_ATTRIBUTE); //replacer属性 String callback = replacedMethodEle.getAttribute(REPLACER_ATTRIBUTE); ReplaceOverride replaceOverride = new ReplaceOverride(name, callback); //获取arg-type标签，参数类型 // Look for arg-type match elements. List<Element> argTypeEles = DomUtils.getChildElementsByTagName(replacedMethodEle, ARG_TYPE_ELEMENT); //获取参数类型，并保存 for (Element argTypeEle : argTypeEles) { String match = argTypeEle.getAttribute(ARG_TYPE_MATCH_ATTRIBUTE); match = (StringUtils.hasText(match) ? match : DomUtils.getTextValue(argTypeEle)); if (StringUtils.hasText(match)) { replaceOverride.addTypeIdentifier(match); } } replaceOverride.setSource(extractSource(replacedMethodEle)); overrides.addOverride(replaceOverride); } }}4.子元素constructor-arg解析
4.1 举例说明
举个例子的话，会更直观一点：
public class Man { private String name ; private int age; private List hobby; private Map friends; private Set set; private boolean ifMarried; public Man() { } public Man(String name, int age,List hobby,Map friends,Set set,boolean ifMarried){ this.name = name; this.age = age; this.hobby = hobby; this.friends = friends; this.set = set; this.ifMarried = ifMarried; } public String getInfo(){ String info = "姓名："+this.name+"\n年龄:"+this.age+"\n爱好:"+this.hobby+"\n朋友:"+this.friends+"\n婚否:"+this.ifMarried+"\n其他的："+this.set; return info; } }<bean id="man" class="com.spring.test.Man"> <constructor-arg value="zzy" index="0"></constructor-arg> <constructor-arg value="10" index="1"></constructor-arg> <constructor-arg> <list> <value>movie</value> <value>music</value> </list> </constructor-arg> <constructor-arg> <set> <value>Lady is GaGa</value> <value>GaGa is Lady</value> </set> </constructor-arg> <constructor-arg> <map> <entry key="liuhua" value="man"></entry> <entry key="xujinglei" value="female"></entry> </map> </constructor-arg> <constructor-arg index="5" value="0"></constructor-arg> </bean> 4.2 具体代码解析
对于construction-arg 子元素的解析,spring 是通过 BeanDefinitionParserDelegate. parseConstructorArgElements(Element beanEle, BeanDefinition bd); 方法来实现的：
/** * Parse constructor-arg sub-elements of the given bean element. */public void parseConstructorArgElements(Element beanEle, BeanDefinition bd) { NodeList nl = beanEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, CONSTRUCTOR_ARG_ELEMENT)) { //解析constructor-arg parseConstructorArgElement((Element) node, bd); } }}追踪下去如下:
/** * 解析constructor-arg元素 */public void parseConstructorArgElement(Element ele, BeanDefinition bd) { //index属性 String indexAttr = ele.getAttribute(INDEX_ATTRIBUTE); //type属性 String typeAttr = ele.getAttribute(TYPE_ATTRIBUTE); //name属性 String nameAttr = ele.getAttribute(NAME_ATTRIBUTE); //如果constructor-arg标签index属性有值 if (StringUtils.hasLength(indexAttr)) { try { int index = Integer.parseInt(indexAttr); if (index < 0) { error("'index' cannot be lower than 0", ele); } else { try { this.parseState.push(new ConstructorArgumentEntry(index)); //解析constructor-arg标签其他属性值，和子标签 Object value = parsePropertyValue(ele, bd, null); ConstructorArgumentValues.ValueHolder valueHolder = new ConstructorArgumentValues.ValueHolder(value); if (StringUtils.hasLength(typeAttr)) { valueHolder.setType(typeAttr); } if (StringUtils.hasLength(nameAttr)) { valueHolder.setName(nameAttr); } valueHolder.setSource(extractSource(ele)); if (bd.getConstructorArgumentValues().hasIndexedArgumentValue(index)) { error("Ambiguous constructor-arg entries for index " + index, ele); } else { bd.getConstructorArgumentValues().addIndexedArgumentValue(index, valueHolder); } } finally { this.parseState.pop(); } } } catch (NumberFormatException ex) { error("Attribute 'index' of tag 'constructor-arg' must be an integer", ele); } }//如果constructor-arg标签index属性没有值 else { try { this.parseState.push(new ConstructorArgumentEntry()); //解析constructor-arg标签其他属性值，和子标签 Object value = parsePropertyValue(ele, bd, null); ConstructorArgumentValues.ValueHolder valueHolder = new ConstructorArgumentValues.ValueHolder(value); if (StringUtils.hasLength(typeAttr)) { valueHolder.setType(typeAttr); } if (StringUtils.hasLength(nameAttr)) { valueHolder.setName(nameAttr); } valueHolder.setSource(extractSource(ele)); bd.getConstructorArgumentValues().addGenericArgumentValue(valueHolder); } finally { this.parseState.pop(); } }}从上面的代码上看,对构造函数中属性的解析,经历了以下几个过程:
如果指定了index属性
1. 解析constructor-arg标签
2. ConstructorArgumentValues.ValueHolder类型来封装解析出来的元素
3. 将type、name、index属性一起封装到ConstructorArgumentValues.ValueHolder中。并将ValueHolder中添加至当前BeanDefinition的ConstructorArgumentValues的IndexedArgumentValue中
如果没有指定index属性
1. 解析constructor-arg标签
2. ConstructorArgumentValues.ValueHolder类型来封装解析出来的元素
3. 将type、name、index属性一起封装到ConstructorArgumentValues.ValueHolder中。并将ValueHolder中添加至当前BeanDefinition的ConstructorArgumentValues的GenericArgumentValue中
如果指定了index属性是保存到IndexedArgumentValue中，否则保存到GenericArgumentValue。
public Object parsePropertyValue(Element ele, BeanDefinition bd, String propertyName) { String elementName = (propertyName != null) ? "<property> element for property '" + propertyName + "'" : "<constructor-arg> element"; //一个constructor-arg标签只能有一个子标签：ref，value,list等 NodeList nl = ele.getChildNodes(); Element subElement = null; //判断是否只有一个子标签（忽略description和meta标签） for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (node instanceof Element && !nodeNameEquals(node, DESCRIPTION_ELEMENT) && !nodeNameEquals(node, META_ELEMENT)) { if (subElement != null) { error(elementName + " must not contain more than one sub-element", ele); } else { subElement = (Element) node; } } } //constructor-arg标签的ref属性 boolean hasRefAttribute = ele.hasAttribute(REF_ATTRIBUTE); //constructor-arg标签的value属性 boolean hasValueAttribute = ele.hasAttribute(VALUE_ATTRIBUTE); /** * 1.constructor-arg标签不能同时具有ref和value属性 * 1.constructor-arg如果具有ref和value属性之一，则不能再有子元素（忽略description和meta标签） */ if ((hasRefAttribute && hasValueAttribute) || ((hasRefAttribute || hasValueAttribute) && subElement != null)) { error(elementName + " is only allowed to contain either 'ref' attribute OR 'value' attribute OR sub-element", ele); } //解析constructor-arg标签的ref属性 if (hasRefAttribute) { //获取ref属性值 String refName = ele.getAttribute(REF_ATTRIBUTE); if (!StringUtils.hasText(refName)) { error(elementName + " contains empty 'ref' attribute", ele); } //使用RuntimeBeanReference封装ref属性 RuntimeBeanReference ref = new RuntimeBeanReference(refName); ref.setSource(extractSource(ele)); return ref; } //解析constructor-arg标签的value属性 else if (hasValueAttribute) { //使用TypedStringValue封装value属性 TypedStringValue valueHolder = new TypedStringValue(ele.getAttribute(VALUE_ATTRIBUTE)); valueHolder.setSource(extractSource(ele)); return valueHolder; } //解析constructor-arg标签的子元素 else if (subElement != null) { return parsePropertySubElement(subElement, bd); } else { //如果即没有子元素、也没有ref、value属性，则返回null error(elementName + " must specify a ref or value", ele); return null; }}public Object parsePropertySubElement(Element ele, BeanDefinition bd, String defaultValueType) { if (!isDefaultNamespace(ele)) { return parseNestedCustomElement(ele, bd); } else if (nodeNameEquals(ele, BEAN_ELEMENT)) { BeanDefinitionHolder nestedBd = parseBeanDefinitionElement(ele, bd); if (nestedBd != null) { nestedBd = decorateBeanDefinitionIfRequired(ele, nestedBd, bd); } return nestedBd; } //ref标签解析 else if (nodeNameEquals(ele, REF_ELEMENT)) { // A generic reference to any name of any bean. String refName = ele.getAttribute(BEAN_REF_ATTRIBUTE); boolean toParent = false; if (!StringUtils.hasLength(refName)) { // A reference to the id of another bean in the same XML file. refName = ele.getAttribute(LOCAL_REF_ATTRIBUTE); if (!StringUtils.hasLength(refName)) { // A reference to the id of another bean in a parent context. refName = ele.getAttribute(PARENT_REF_ATTRIBUTE); toParent = true; if (!StringUtils.hasLength(refName)) { error("'bean', 'local' or 'parent' is required for <ref> element", ele); return null; } } } if (!StringUtils.hasText(refName)) { error("<ref> element contains empty target attribute", ele); return null; } RuntimeBeanReference ref = new RuntimeBeanReference(refName, toParent); ref.setSource(extractSource(ele)); return ref; } //idref标签解析 else if (nodeNameEquals(ele, IDREF_ELEMENT)) { return parseIdRefElement(ele); } //value标签解析 else if (nodeNameEquals(ele, VALUE_ELEMENT)) { return parseValueElement(ele, defaultValueType); } //null标签继续 else if (nodeNameEquals(ele, NULL_ELEMENT)) { // It's a distinguished null value. Let's wrap it in a TypedStringValue // object in order to preserve the source location. TypedStringValue nullHolder = new TypedStringValue(null); nullHolder.setSource(extractSource(ele)); return nullHolder; } //array标签解析 else if (nodeNameEquals(ele, ARRAY_ELEMENT)) { return parseArrayElement(ele, bd); } //list标签解析 else if (nodeNameEquals(ele, LIST_ELEMENT)) { return parseListElement(ele, bd); } //set标签解析 else if (nodeNameEquals(ele, SET_ELEMENT)) { return parseSetElement(ele, bd); } //map标签解析 else if (nodeNameEquals(ele, MAP_ELEMENT)) { return parseMapElement(ele, bd); } //props标签解析 else if (nodeNameEquals(ele, PROPS_ELEMENT)) { return parsePropsElement(ele); } else { error("Unknown property sub-element: [" + ele.getNodeName() + "]", ele); return null; }}5.子元素propertyg解析
5.1 基本用法
public class Animal {public String type;public Set<Integer> age;private Map<String, Integer> sell;public Animal() {}/** * @return the type */public String getType() { return type;}/** * @param type the type to set */public void setType(String type) { this.type = type;}/** * @return the age */public Set<Integer> getAge() { return age;}/** * @param age the age to set */public void setAge(Set<Integer> age) { this.age = age;}/** * @return the sell */public Map<String, Integer> getSell() { return sell;}/** * @param sell the sell to set */public void setSell(Map<String, Integer> sell) { this.sell = sell;}/* * (non-Javadoc) * * @see java.lang.Object#toString() */@Overridepublic String toString() { return "Animal [type=" + type + ", age=" + age + ", sell=" + sell + "]";}}<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean id="animal" class="test.property.Animal"> <property name="type" value="cat"></property> <property name="age"> <set> <value>1</value> <value>2</value> <value>3</value> </set> </property> <property name="sell"> <map> <entry key="blue" value="111"></entry> <entry key="red" value="22"></entry> </map> </property> </bean></beans>5.2 具体代码解析
/** * Parse property sub-elements of the given bean element. */public void parsePropertyElements(Element beanEle, BeanDefinition bd) { NodeList nl = beanEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, PROPERTY_ELEMENT)) { // 这里进去 parsePropertyElement((Element) node, bd); } }}/** * Parse a property element. */public void parsePropertyElement(Element ele, BeanDefinition bd) { // 获取配置文件中name 的值 String propertyName = ele.getAttribute(NAME_ATTRIBUTE); if (!StringUtils.hasLength(propertyName)) { error("Tag 'property' must have a 'name' attribute", ele); return; } this.parseState.push(new PropertyEntry(propertyName)); try { // 不容许多次对同一属性配置 if (bd.getPropertyValues().contains(propertyName)) { error("Multiple 'property' definitions for property '" + propertyName + "'", ele); return; } Object val = parsePropertyValue(ele, bd, propertyName); PropertyValue pv = new PropertyValue(propertyName, val); parseMetaElements(ele, pv); pv.setSource(extractSource(ele)); bd.getPropertyValues().addPropertyValue(pv); } finally { this.parseState.pop(); }}public Object parsePropertyValue(Element ele, BeanDefinition bd, String propertyName) { String elementName = (propertyName != null) ? "<property> element for property '" + propertyName + "'" : "<constructor-arg> element"; // Should only have one child element: ref, value, list, etc. // 应该只有一个子元素：REF，值，列表等。 NodeList nl = ele.getChildNodes(); Element subElement = null; for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); // 对应的description 或者meta不处理 if (node instanceof Element && !nodeNameEquals(node, DESCRIPTION_ELEMENT) && !nodeNameEquals(node, META_ELEMENT)) { // Child element is what we're looking for. if (subElement != null) { error(elementName + " must not contain more than one sub-element", ele); } else { subElement = (Element) node; } } } // 解析 ref boolean hasRefAttribute = ele.hasAttribute(REF_ATTRIBUTE); // 解析 value boolean hasValueAttribute = ele.hasAttribute(VALUE_ATTRIBUTE); if ((hasRefAttribute && hasValueAttribute) || ((hasRefAttribute || hasValueAttribute) && subElement != null)) { /* * 1.不能同时有ref 又有 value * 2.不能存在ref 或者 value 又有子元素 */ error(elementName + " is only allowed to contain either 'ref' attribute OR 'value' attribute OR sub-element", ele); } if (hasRefAttribute) { String refName = ele.getAttribute(REF_ATTRIBUTE); if (!StringUtils.hasText(refName)) { error(elementName + " contains empty 'ref' attribute", ele); } // ref 属性的处理 , 使用RuntimeBeanReference封装对应的ref名称 RuntimeBeanReference ref = new RuntimeBeanReference(refName); ref.setSource(extractSource(ele)); return ref; } else if (hasValueAttribute) { // Value 属性的处理 , 使用TypedStringValue封装对应的 TypedStringValue valueHolder = new TypedStringValue( ele.getAttribute(VALUE_ATTRIBUTE)); valueHolder.setSource(extractSource(ele)); return valueHolder; } else if (subElement != null) { // 解析子元素 return parsePropertySubElement(subElement, bd); } else { // Neither child element nor "ref" or "value" attribute found. // 对于没有ref 也没有子元素的,Spring只好丢出异常 error(elementName + " must specify a ref or value", ele); return null; }}6.子元素qualifier解析
<bean id="test" class="com.demo.test"> <qualifier type="org.Springframework.beans.factory.annotation.Qualifier" value="ts"/></bean>public void parseQualifierElements(Element beanEle, AbstractBeanDefinition bd) { NodeList nl = beanEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (isCandidateElement(node) && nodeNameEquals(node, QUALIFIER_ELEMENT)) { parseQualifierElement((Element) node, bd); } }}public void parseQualifierElement(Element ele, AbstractBeanDefinition bd) { String typeName = ele.getAttribute(TYPE_ATTRIBUTE); //必须要有type属性 if (!StringUtils.hasLength(typeName)) { error("Tag 'qualifier' must have a 'type' attribute", ele); return; } this.parseState.push(new QualifierEntry(typeName)); try { //使用AutowireCandidateQualifier封装 AutowireCandidateQualifier qualifier = new AutowireCandidateQualifier(typeName); qualifier.setSource(extractSource(ele)); //value属性 String value = ele.getAttribute(VALUE_ATTRIBUTE); if (StringUtils.hasLength(value)) { qualifier.setAttribute(AutowireCandidateQualifier.VALUE_KEY, value); } NodeList nl = ele.getChildNodes(); //解析子标签 for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); //解析子标签attribute if (isCandidateElement(node) && nodeNameEquals(node, QUALIFIER_ATTRIBUTE_ELEMENT)) { Element attributeEle = (Element) node; String attributeName = attributeEle.getAttribute(KEY_ATTRIBUTE); String attributeValue = attributeEle.getAttribute(VALUE_ATTRIBUTE); if (StringUtils.hasLength(attributeName) && StringUtils.hasLength(attributeValue)) { BeanMetadataAttribute attribute = new BeanMetadataAttribute(attributeName, attributeValue); attribute.setSource(extractSource(attributeEle)); qualifier.addMetadataAttribute(attribute); } else { error("Qualifier 'attribute' tag must have a 'name' and 'value'", attributeEle); return; } } } bd.addQualifier(qualifier); } finally { this.parseState.pop(); }}阅读全文
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