Ioc容器依赖注入－Spring 源码系列（2）
Ioc容器依赖注入－Spring 源码系列（2）
目录：
Ioc容器beanDefinition－Spring 源码（1）
Ioc容器BeanPostProcessor－Spring 源码（3）
上篇中组装出了一个beanName:beanDefinition的ConcurrentHashMap，接下来就是把这些bean像织网一样联系起来。
从AbstractBeanFactory的getBean方法入手：
@Override public Object getBean(String name) throws BeansException { return doGetBean(name, null, null, false); } @Override public <T> T getBean(String name, Class<T> requiredType) throws BeansException { return doGetBean(name, requiredType, null, false); } @Override public Object getBean(String name, Object... args) throws BeansException { return doGetBean(name, null, args, false); } public <T> T getBean(String name, Class<T> requiredType, Object... args) throws BeansException { return doGetBean(name, requiredType, args, false); }
doGetBean方法：
protected <T> T doGetBean( final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly) throws BeansException { //筛选出null，&符号的代表自身 final String beanName = transformedBeanName(name); Object bean; // 先获取从单例缓存中获取单例的bean，无需再进行实例化去创建了 Object sharedInstance = getSingleton(beanName); if (sharedInstance != null && args == null) { if (logger.isDebugEnabled()) { if (isSingletonCurrentlyInCreation(beanName)) { logger.debug("Returning eagerly cached instance of singleton bean '" + beanName + "' that is not fully initialized yet - a consequence of a circular reference"); } else { logger.debug("Returning cached instance of singleton bean '" + beanName + "'"); } } // 是FactoryBean情况 bean = getObjectForBeanInstance(sharedInstance, name, beanName, null); } else { // Fail if we're already creating this bean instance: // We're assumably within a circular reference. if (isPrototypeCurrentlyInCreation(beanName)) { throw new BeanCurrentlyInCreationException(beanName); } // Check if bean definition exists in this factory. BeanFactory parentBeanFactory = getParentBeanFactory(); if (parentBeanFactory != null && !containsBeanDefinition(beanName)) { // Not found -> check parent. String nameToLookup = originalBeanName(name); if (args != null) { // Delegation to parent with explicit args. return (T) parentBeanFactory.getBean(nameToLookup, args); } else { // No args -> delegate to standard getBean method. return parentBeanFactory.getBean(nameToLookup, requiredType); } } if (!typeCheckOnly) { markBeanAsCreated(beanName); } try { final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); checkMergedBeanDefinition(mbd, beanName, args); // 获取这个bean依赖的对象，进入for循环迭代调用getBean方法，开始织网 String[] dependsOn = mbd.getDependsOn(); if (dependsOn != null) { for (String dependsOnBean : dependsOn) { if (isDependent(beanName, dependsOnBean)) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Circular depends-on relationship between '" + beanName + "' and '" + dependsOnBean + "'"); } registerDependentBean(dependsOnBean, beanName); // 迭代 getBean(dependsOnBean); } } // 最终创建bean // 单例 if (mbd.isSingleton()) { sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { try { return createBean(beanName, mbd, args); } catch (BeansException ex) { // Explicitly remove instance from singleton cache: It might have been put there // eagerly by the creation process, to allow for circular reference resolution. // Also remove any beans that received a temporary reference to the bean. destroySingleton(beanName); throw ex; } } }); bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd); } // 多例 else if (mbd.isPrototype()) { // It's a prototype -> create a new instance. Object prototypeInstance = null; try { beforePrototypeCreation(beanName); prototypeInstance = createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd); } // 自定义配置的scop else { String scopeName = mbd.getScope(); final Scope scope = this.scopes.get(scopeName); if (scope == null) { throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'"); } try { Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { beforePrototypeCreation(beanName); try { return createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } } }); bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd); } catch (IllegalStateException ex) { throw new BeanCreationException(beanName, "Scope '" + scopeName + "' is not active for the current thread; consider " + "defining a scoped proxy for this bean if you intend to refer to it from a singleton", ex); } } } catch (BeansException ex) { cleanupAfterBeanCreationFailure(beanName); throw ex; } } // Check if required type matches the type of the actual bean instance. if (requiredType != null && bean != null && !requiredType.isAssignableFrom(bean.getClass())) { try { return getTypeConverter().convertIfNecessary(bean, requiredType); } catch (TypeMismatchException ex) { if (logger.isDebugEnabled()) { logger.debug("Failed to convert bean '" + name + "' to required type [" + ClassUtils.getQualifiedName(requiredType) + "]", ex); } throw new BeanNotOfRequiredTypeException(name, requiredType, bean.getClass()); } } return (T) bean; }
无论单例还是多例模式的scop都是调用AbstractAutowireCapableBeanFactory的createBean方法－>doCreateBean方法来创建bean：
protected Object createBean(String beanName, RootBeanDefinition mbd, Object[] args) throws BeanCreationException { if (logger.isDebugEnabled()) { logger.debug("Creating instance of bean '" + beanName + "'"); } RootBeanDefinition mbdToUse = mbd; // Make sure bean class is actually resolved at this point, and // clone the bean definition in case of a dynamically resolved Class // which cannot be stored in the shared merged bean definition. Class<?> resolvedClass = resolveBeanClass(mbd, beanName); if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) { mbdToUse = new RootBeanDefinition(mbd); mbdToUse.setBeanClass(resolvedClass); } // Prepare method overrides. try { mbdToUse.prepareMethodOverrides(); } catch (BeanDefinitionValidationException ex) { throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(), beanName, "Validation of method overrides failed", ex); } try { // Give BeanPostProcessors a chance to return a proxy instead of the target bean instance. Object bean = resolveBeforeInstantiation(beanName, mbdToUse); if (bean != null) { return bean; } } catch (Throwable ex) { throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName, "BeanPostProcessor before instantiation of bean failed", ex); } Object beanInstance = doCreateBean(beanName, mbdToUse, args); if (logger.isDebugEnabled()) { logger.debug("Finished creating instance of bean '" + beanName + "'"); } return beanInstance; } protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) { // Instantiate the bean. BeanWrapper instanceWrapper = null; if (mbd.isSingleton()) { instanceWrapper = this.factoryBeanInstanceCache.remove(beanName); } if (instanceWrapper == null) { instanceWrapper = createBeanInstance(beanName, mbd, args); } final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null); Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null); // Allow post-processors to modify the merged bean definition. synchronized (mbd.postProcessingLock) { if (!mbd.postProcessed) { applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName); mbd.postProcessed = true; } } // Eagerly cache singletons to be able to resolve circular references // even when triggered by lifecycle interfaces like BeanFactoryAware. boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences && isSingletonCurrentlyInCreation(beanName)); if (earlySingletonExposure) { if (logger.isDebugEnabled()) { logger.debug("Eagerly caching bean '" + beanName + "' to allow for resolving potential circular references"); } addSingletonFactory(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { return getEarlyBeanReference(beanName, mbd, bean); } }); } // Initialize the bean instance. Object exposedObject = bean; try { populateBean(beanName, mbd, instanceWrapper); if (exposedObject != null) { exposedObject = initializeBean(beanName, exposedObject, mbd); } } catch (Throwable ex) { if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) { throw (BeanCreationException) ex; } else { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex); } } if (earlySingletonExposure) { Object earlySingletonReference = getSingleton(beanName, false); if (earlySingletonReference != null) { if (exposedObject == bean) { exposedObject = earlySingletonReference; } else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) { String[] dependentBeans = getDependentBeans(beanName); Set<String> actualDependentBeans = new LinkedHashSet<String>(dependentBeans.length); for (String dependentBean : dependentBeans) { if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) { actualDependentBeans.add(dependentBean); } } if (!actualDependentBeans.isEmpty()) { throw new BeanCurrentlyInCreationException(beanName, "Bean with name '" + beanName + "' has been injected into other beans [" + StringUtils.collectionToCommaDelimitedString(actualDependentBeans) + "] in its raw version as part of a circular reference, but has eventually been " + "wrapped. This means that said other beans do not use the final version of the " + "bean. This is often the result of over-eager type matching - consider using " + "'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example."); } } } } // Register bean as disposable. try { registerDisposableBeanIfNecessary(beanName, bean, mbd); } catch (BeanDefinitionValidationException ex) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex); } return exposedObject; }
以上的单例部分交由DefaultSingletonBeanRegistry管理，采用Registry of Singleton 模式，我在单例的文章里也补充了
可以想象：网由点和线组成
1，createBeanInstance(beanName, mbd, args)生成包装了bean的对象，就是生成好点。
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, Object[] args) { // Make sure bean class is actually resolved at this point. Class<?> beanClass = resolveBeanClass(mbd, beanName); if (beanClass != null && !Modifier.isPublic(beanClass.getModifiers()) && !mbd.isNonPublicAccessAllowed()) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Bean class isn't public, and non-public access not allowed: " + beanClass.getName()); } // 工厂方法创建bean if (mbd.getFactoryMethodName() != null) { return instantiateUsingFactoryMethod(beanName, mbd, args); } // Shortcut when re-creating the same bean... boolean resolved = false; boolean autowireNecessary = false; if (args == null) { synchronized (mbd.constructorArgumentLock) { if (mbd.resolvedConstructorOrFactoryMethod != null) { resolved = true; autowireNecessary = mbd.constructorArgumentsResolved; } } } if (resolved) { if (autowireNecessary) { return autowireConstructor(beanName, mbd, null, null); } else { return instantiateBean(beanName, mbd); } } // 使用构造函数创建bean Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName); if (ctors != null || mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_CONSTRUCTOR || mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) { return autowireConstructor(beanName, mbd, ctors, args); } // 使用默认的构造函数创建bean return instantiateBean(beanName, mbd); } // 使用默认的构造函数创建bean protected BeanWrapper instantiateBean(final String beanName, final RootBeanDefinition mbd) { try { Object beanInstance; final BeanFactory parent = this; if (System.getSecurityManager() != null) { beanInstance = AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { // return getInstantiationStrategy().instantiate(mbd, beanName, parent); } }, getAccessControlContext()); } else { beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, parent); } BeanWrapper bw = new BeanWrapperImpl(beanInstance); initBeanWrapper(bw); return bw; } catch (Throwable ex) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Instantiation of bean failed", ex); } }
SimpleInstantiationStrategy的instantiate(RootBeanDefinition bd, String beanName, BeanFactory owner)方法：
public Object instantiate(RootBeanDefinition bd, String beanName, BeanFactory owner) { // 如果没有override method 就走构造函数 否则走CGLIB if (bd.getMethodOverrides().isEmpty()) { Constructor<?> constructorToUse; synchronized (bd.constructorArgumentLock) { constructorToUse = (Constructor<?>) bd.resolvedConstructorOrFactoryMethod; if (constructorToUse == null) { final Class<?> clazz = bd.getBeanClass(); if (clazz.isInterface()) { throw new BeanInstantiationException(clazz, "Specified class is an interface"); } try { if (System.getSecurityManager() != null) { constructorToUse = AccessController.doPrivileged(new PrivilegedExceptionAction<Constructor<?>>() { @Override public Constructor<?> run() throws Exception { return clazz.getDeclaredConstructor((Class[]) null); } }); } else { constructorToUse = clazz.getDeclaredConstructor((Class[]) null); } bd.resolvedConstructorOrFactoryMethod = constructorToUse; } catch (Exception ex) { throw new BeanInstantiationException(clazz, "No default constructor found", ex); } } } // BeanUtils 方法 return BeanUtils.instantiateClass(constructorToUse); } else { // Must generate CGLIB subclass. return instantiateWithMethodInjection(bd, beanName, owner); } }
以上已经把ioc容器管理的bean创建的过程都走完了，接下来就是把这些bean之间的关系建立起来，有了点，再做一下线，就可以变成网了。
2，populateBean(beanName, mbd, instanceWrapper);方法来做好线的事。
protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) { // 需要注入的值 PropertyValues pvs = mbd.getPropertyValues(); if (bw == null) { if (!pvs.isEmpty()) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance"); } else { // Skip property population phase for null instance. return; } } // Give any InstantiationAwareBeanPostProcessors the opportunity to modify the // state of the bean before properties are set. This can be used, for example, // to support styles of field injection. boolean continueWithPropertyPopulation = true; if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { continueWithPropertyPopulation = false; break; } } } } if (!continueWithPropertyPopulation) { return; } if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME || mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) { MutablePropertyValues newPvs = new MutablePropertyValues(pvs); // Add property values based on autowire by name if applicable. if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME) { autowireByName(beanName, mbd, bw, newPvs); } // Add property values based on autowire by type if applicable. if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) { autowireByType(beanName, mbd, bw, newPvs); } pvs = newPvs; } boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors(); boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE); if (hasInstAwareBpps || needsDepCheck) { PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); if (hasInstAwareBpps) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName); if (pvs == null) { return; } } } } if (needsDepCheck) { checkDependencies(beanName, mbd, filteredPds, pvs); } } // 注入操作 applyPropertyValues(beanName, mbd, bw, pvs); } protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) { if (pvs == null || pvs.isEmpty()) { return; } MutablePropertyValues mpvs = null; List<PropertyValue> original; if (System.getSecurityManager() != null) { if (bw instanceof BeanWrapperImpl) { ((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext()); } } if (pvs instanceof MutablePropertyValues) { mpvs = (MutablePropertyValues) pvs; if (mpvs.isConverted()) { // Shortcut: use the pre-converted values as-is. try { bw.setPropertyValues(mpvs); return; } catch (BeansException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Error setting property values", ex); } } original = mpvs.getPropertyValueList(); } else { original = Arrays.asList(pvs.getPropertyValues()); } TypeConverter converter = getCustomTypeConverter(); if (converter == null) { converter = bw; } //处理类 BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter); // Create a deep copy, resolving any references for values. List<PropertyValue> deepCopy = new ArrayList<PropertyValue>(original.size()); boolean resolveNecessary = false; for (PropertyValue pv : original) { if (pv.isConverted()) { deepCopy.add(pv); } else { String propertyName = pv.getName(); Object originalValue = pv.getValue(); // Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue); Object convertedValue = resolvedValue; boolean convertible = bw.isWritableProperty(propertyName) && !PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName); if (convertible) { convertedValue = convertForProperty(resolvedValue, propertyName, bw, converter); } // Possibly store converted value in merged bean definition, // in order to avoid re-conversion for every created bean instance. if (resolvedValue == originalValue) { if (convertible) { pv.setConvertedValue(convertedValue); } deepCopy.add(pv); } else if (convertible && originalValue instanceof TypedStringValue && !((TypedStringValue) originalValue).isDynamic() && !(convertedValue instanceof Collection || ObjectUtils.isArray(convertedValue))) { pv.setConvertedValue(convertedValue); deepCopy.add(pv); } else { resolveNecessary = true; deepCopy.add(new PropertyValue(pv, convertedValue)); } } } if (mpvs != null && !resolveNecessary) { mpvs.setConverted(); } // Set our (possibly massaged) deep copy. try { bw.setPropertyValues(new MutablePropertyValues(deepCopy)); } catch (BeansException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Error setting property values", ex); } }
什么类型都会调用到TypeConverterDelegate.convertIfNecessary来获得注入的bean
public <T> T convertIfNecessary(String propertyName, Object oldValue, Object newValue, Class<T> requiredType, TypeDescriptor typeDescriptor) throws IllegalArgumentException { // Custom editor for this type? PropertyEditor editor = this.propertyEditorRegistry.findCustomEditor(requiredType, propertyName); ConversionFailedException conversionAttemptEx = null; // No custom editor but custom ConversionService specified? ConversionService conversionService = this.propertyEditorRegistry.getConversionService(); if (editor == null && conversionService != null && newValue != null && typeDescriptor != null) { TypeDescriptor sourceTypeDesc = TypeDescriptor.forObject(newValue); if (conversionService.canConvert(sourceTypeDesc, typeDescriptor)) { try { return (T) conversionService.convert(newValue, sourceTypeDesc, typeDescriptor); } catch (ConversionFailedException ex) { // fallback to default conversion logic below conversionAttemptEx = ex; } } } Object convertedValue = newValue; // Value not of required type? if (editor != null || (requiredType != null && !ClassUtils.isAssignableValue(requiredType, convertedValue))) { if (requiredType != null && Collection.class.isAssignableFrom(requiredType) && convertedValue instanceof String) { TypeDescriptor elementType = typeDescriptor.getElementTypeDescriptor(); if (elementType != null && Enum.class.isAssignableFrom(elementType.getType())) { convertedValue = StringUtils.commaDelimitedListToStringArray((String) convertedValue); } } if (editor == null) { editor = findDefaultEditor(requiredType); } convertedValue = doConvertValue(oldValue, convertedValue, requiredType, editor); } boolean standardConversion = false; if (requiredType != null) { // Try to apply some standard type conversion rules if appropriate. if (convertedValue != null) { if (Object.class == requiredType) { return (T) convertedValue; } else if (requiredType.isArray()) { // Array required -> apply appropriate conversion of elements. if (convertedValue instanceof String && Enum.class.isAssignableFrom(requiredType.getComponentType())) { convertedValue = StringUtils.commaDelimitedListToStringArray((String) convertedValue); } return (T) convertToTypedArray(convertedValue, propertyName, requiredType.getComponentType()); } else if (convertedValue instanceof Collection) { // Convert elements to target type, if determined. convertedValue = convertToTypedCollection( (Collection<?>) convertedValue, propertyName, requiredType, typeDescriptor); standardConversion = true; } else if (convertedValue instanceof Map) { // Convert keys and values to respective target type, if determined. convertedValue = convertToTypedMap( (Map<?, ?>) convertedValue, propertyName, requiredType, typeDescriptor); standardConversion = true; } if (convertedValue.getClass().isArray() && Array.getLength(convertedValue) == 1) { convertedValue = Array.get(convertedValue, 0); standardConversion = true; } if (String.class == requiredType && ClassUtils.isPrimitiveOrWrapper(convertedValue.getClass())) { // We can stringify any primitive value... return (T) convertedValue.toString(); } else if (convertedValue instanceof String && !requiredType.isInstance(convertedValue)) { if (conversionAttemptEx == null && !requiredType.isInterface() && !requiredType.isEnum()) { try { Constructor<T> strCtor = requiredType.getConstructor(String.class); return BeanUtils.instantiateClass(strCtor, convertedValue); } catch (NoSuchMethodException ex) { // proceed with field lookup if (logger.isTraceEnabled()) { logger.trace("No String constructor found on type [" + requiredType.getName() + "]", ex); } } catch (Exception ex) { if (logger.isDebugEnabled()) { logger.debug("Construction via String failed for type [" + requiredType.getName() + "]", ex); } } } String trimmedValue = ((String) convertedValue).trim(); if (requiredType.isEnum() && "".equals(trimmedValue)) { // It's an empty enum identifier: reset the enum value to null. return null; } convertedValue = attemptToConvertStringToEnum(requiredType, trimmedValue, convertedValue); standardConversion = true; } else if (convertedValue instanceof Number && Number.class.isAssignableFrom(requiredType)) { convertedValue = NumberUtils.convertNumberToTargetClass( (Number) convertedValue, (Class<Number>) requiredType); standardConversion = true; } } else { // convertedValue == null if (javaUtilOptionalEmpty != null && requiredType.equals(javaUtilOptionalEmpty.getClass())) { convertedValue = javaUtilOptionalEmpty; } } if (!ClassUtils.isAssignableValue(requiredType, convertedValue)) { if (conversionAttemptEx != null) { // Original exception from former ConversionService call above... throw conversionAttemptEx; } else if (conversionService != null) { // ConversionService not tried before, probably custom editor found // but editor couldn't produce the required type... TypeDescriptor sourceTypeDesc = TypeDescriptor.forObject(newValue); if (conversionService.canConvert(sourceTypeDesc, typeDescriptor)) { return (T) conversionService.convert(newValue, sourceTypeDesc, typeDescriptor); } } // Definitely doesn't match: throw IllegalArgumentException/IllegalStateException StringBuilder msg = new StringBuilder(); msg.append("Cannot convert value of type [").append(ClassUtils.getDescriptiveType(newValue)); msg.append("] to required type [").append(ClassUtils.getQualifiedName(requiredType)).append("]"); if (propertyName != null) { msg.append(" for property '").append(propertyName).append("'"); } if (editor != null) { msg.append(": PropertyEditor [").append(editor.getClass().getName()).append( "] returned inappropriate value of type [").append( ClassUtils.getDescriptiveType(convertedValue)).append("]"); throw new IllegalArgumentException(msg.toString()); } else { msg.append(": no matching editors or conversion strategy found"); throw new IllegalStateException(msg.toString()); } } } if (conversionAttemptEx != null) { if (editor == null && !standardConversion && requiredType != null && Object.class != requiredType) { throw conversionAttemptEx; } logger.debug("Original ConversionService attempt failed - ignored since " + "PropertyEditor based conversion eventually succeeded", conversionAttemptEx); } return (T) convertedValue; }
放入bean的操作是BeanWrapperImpl的基类上的setPropertyValue实现
protected void setPropertyValue(PropertyTokenHolder tokens, PropertyValue pv) throws BeansException { String propertyName = tokens.canonicalName; String actualName = tokens.actualName; if (tokens.keys != null) { // Apply indexes and map keys: fetch value for all keys but the last one. PropertyTokenHolder getterTokens = new PropertyTokenHolder(); getterTokens.canonicalName = tokens.canonicalName; getterTokens.actualName = tokens.actualName; getterTokens.keys = new String[tokens.keys.length - 1]; System.arraycopy(tokens.keys, 0, getterTokens.keys, 0, tokens.keys.length - 1); Object propValue; try { propValue = getPropertyValue(getterTokens); } catch (NotReadablePropertyException ex) { throw new NotWritablePropertyException(getRootClass(), this.nestedPath + propertyName, "Cannot access indexed value in property referenced " + "in indexed property path '" + propertyName + "'", ex); } // Set value for last key. String key = tokens.keys[tokens.keys.length - 1]; if (propValue == null) { // null map value case if (isAutoGrowNestedPaths()) { // TODO: cleanup, this is pretty hacky int lastKeyIndex = tokens.canonicalName.lastIndexOf('['); getterTokens.canonicalName = tokens.canonicalName.substring(0, lastKeyIndex); propValue = setDefaultValue(getterTokens); } else { throw new NullValueInNestedPathException(getRootClass(), this.nestedPath + propertyName, "Cannot access indexed value in property referenced " + "in indexed property path '" + propertyName + "': returned null"); } } if (propValue.getClass().isArray()) { PropertyHandler ph = getLocalPropertyHandler(actualName); Class<?> requiredType = propValue.getClass().getComponentType(); int arrayIndex = Integer.parseInt(key); Object oldValue = null; try { if (isExtractOldValueForEditor() && arrayIndex < Array.getLength(propValue)) { oldValue = Array.get(propValue, arrayIndex); } Object convertedValue = convertIfNecessary(propertyName, oldValue, pv.getValue(), requiredType, ph.nested(tokens.keys.length)); int length = Array.getLength(propValue); if (arrayIndex >= length && arrayIndex < this.autoGrowCollectionLimit) { Class<?> componentType = propValue.getClass().getComponentType(); Object newArray = Array.newInstance(componentType, arrayIndex + 1); System.arraycopy(propValue, 0, newArray, 0, length); setPropertyValue(actualName, newArray); propValue = getPropertyValue(actualName); } Array.set(propValue, arrayIndex, convertedValue); } catch (IndexOutOfBoundsException ex) { throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName, "Invalid array index in property path '" + propertyName + "'", ex); } } else if (propValue instanceof List) { PropertyHandler ph = getPropertyHandler(actualName); Class<?> requiredType = ph.getCollectionType(tokens.keys.length); List<Object> list = (List<Object>) propValue; int index = Integer.parseInt(key); Object oldValue = null; if (isExtractOldValueForEditor() && index < list.size()) { oldValue = list.get(index); } Object convertedValue = convertIfNecessary(propertyName, oldValue, pv.getValue(), requiredType, ph.nested(tokens.keys.length)); int size = list.size(); if (index >= size && index < this.autoGrowCollectionLimit) { for (int i = size; i < index; i++) { try { list.add(null); } catch (NullPointerException ex) { throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName, "Cannot set element with index " + index + " in List of size " + size + ", accessed using property path '" + propertyName + "': List does not support filling up gaps with null elements"); } } list.add(convertedValue); } else { try { list.set(index, convertedValue); } catch (IndexOutOfBoundsException ex) { throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName, "Invalid list index in property path '" + propertyName + "'", ex); } } } else if (propValue instanceof Map) { PropertyHandler ph = getLocalPropertyHandler(actualName); Class<?> mapKeyType = ph.getMapKeyType(tokens.keys.length); Class<?> mapValueType = ph.getMapValueType(tokens.keys.length); Map<Object, Object> map = (Map<Object, Object>) propValue; // IMPORTANT: Do not pass full property name in here - property editors // must not kick in for map keys but rather only for map values. TypeDescriptor typeDescriptor = TypeDescriptor.valueOf(mapKeyType); Object convertedMapKey = convertIfNecessary(null, null, key, mapKeyType, typeDescriptor); Object oldValue = null; if (isExtractOldValueForEditor()) { oldValue = map.get(convertedMapKey); } // Pass full property name and old value in here, since we want full // conversion ability for map values. Object convertedMapValue = convertIfNecessary(propertyName, oldValue, pv.getValue(), mapValueType, ph.nested(tokens.keys.length)); map.put(convertedMapKey, convertedMapValue); } else { throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName, "Property referenced in indexed property path '" + propertyName + "' is neither an array nor a List nor a Map; returned value was [" + propValue + "]"); } } else { PropertyHandler ph = getLocalPropertyHandler(actualName); if (ph == null || !ph.isWritable()) { if (pv.isOptional()) { if (logger.isDebugEnabled()) { logger.debug("Ignoring optional value for property '" + actualName + "' - property not found on bean class [" + getRootClass().getName() + "]"); } return; } else { throw createNotWritablePropertyException(propertyName); } } Object oldValue = null; try { Object originalValue = pv.getValue(); Object valueToApply = originalValue; if (!Boolean.FALSE.equals(pv.conversionNecessary)) { if (pv.isConverted()) { valueToApply = pv.getConvertedValue(); } else { if (isExtractOldValueForEditor() && ph.isReadable()) { try { oldValue = ph.getValue(); } catch (Exception ex) { if (ex instanceof PrivilegedActionException) { ex = ((PrivilegedActionException) ex).getException(); } if (logger.isDebugEnabled()) { logger.debug("Could not read previous value of property '" + this.nestedPath + propertyName + "'", ex); } } } valueToApply = convertForProperty( propertyName, oldValue, originalValue, ph.toTypeDescriptor()); } pv.getOriginalPropertyValue().conversionNecessary = (valueToApply != originalValue); } ph.setValue(object, valueToApply); } catch (TypeMismatchException ex) { throw ex; } catch (InvocationTargetException ex) { PropertyChangeEvent propertyChangeEvent = new PropertyChangeEvent(this.rootObject, this.nestedPath + propertyName, oldValue, pv.getValue()); if (ex.getTargetException() instanceof ClassCastException) { throw new TypeMismatchException(propertyChangeEvent, ph.getPropertyType(), ex.getTargetException()); } else { Throwable cause = ex.getTargetException(); if (cause instanceof UndeclaredThrowableException) { // May happen e.g. with Groovy-generated methods cause = cause.getCause(); } throw new MethodInvocationException(propertyChangeEvent, cause); } } catch (Exception ex) { PropertyChangeEvent pce = new PropertyChangeEvent(this.rootObject, this.nestedPath + propertyName, oldValue, pv.getValue()); throw new MethodInvocationException(pce, ex); } } } // 使用反射机制，执行注入set方法注入bean public void setValue(final Object object, Object valueToApply) throws Exception { final Method writeMethod = (this.pd instanceof GenericTypeAwarePropertyDescriptor ? ((GenericTypeAwarePropertyDescriptor) this.pd).getWriteMethodForActualAccess() : this.pd.getWriteMethod()); if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers()) && !writeMethod.isAccessible()) { if (System.getSecurityManager() != null) { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { writeMethod.setAccessible(true); return null; } }); } else { writeMethod.setAccessible(true); } } final Object value = valueToApply; if (System.getSecurityManager() != null) { try { AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() { @Override public Object run() throws Exception { writeMethod.invoke(object, value); return null; } }, acc); } catch (PrivilegedActionException ex) { throw ex.getException(); } } else { writeMethod.invoke(getWrappedInstance(), value); } }
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