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详解Spring支持的各种数据类型的注入，你都用过哪些？( 二 )

spring

  • Collection
  • Map
    •  public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {private Object resolveMultipleBeans(DependencyDescriptor descriptor, @Nullable String beanName,@Nullable Set<String> autowiredBeanNames, @Nullable TypeConverter typeConverter) {Class<?> type = descriptor.getDependencyType();if (descriptor instanceof StreamDependencyDescriptor) {Map<String, Object> matchingBeans = findAutowireCandidates(beanName, type, descriptor);if (autowiredBeanNames != null) {autowiredBeanNames.addAll(matchingBeans.keySet());}Stream<Object> stream = matchingBeans.keySet().stream().map(name -> descriptor.resolveCandidate(name, type, this)).filter(bean -> !(bean instanceof NullBean));if (((StreamDependencyDescriptor) descriptor).isOrdered()) {stream = stream.sorted(adaptOrderComparator(matchingBeans));}return stream;} else if (type.isArray()) {Class<?> componentType = type.getComponentType();ResolvableType resolvableType = descriptor.getResolvableType();Class<?> resolvedArrayType = resolvableType.resolve(type);if (resolvedArrayType != type) {componentType = resolvableType.getComponentType().resolve();}if (componentType == null) {return null;}Map<String, Object> matchingBeans = findAutowireCandidates(beanName, componentType, new MultiElementDescriptor(descriptor));if (matchingBeans.isEmpty()) {return null;}if (autowiredBeanNames != null) {autowiredBeanNames.addAll(matchingBeans.keySet());}TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter());Object result = converter.convertIfNecessary(matchingBeans.values(), resolvedArrayType);if (result instanceof Object[]) {Comparator<Object> comparator = adaptDependencyComparator(matchingBeans);if (comparator != null) {Arrays.sort((Object[]) result, comparator);}}return result;} else if (Collection.class.isAssignableFrom(type) && type.isInterface()) {Class<?> elementType = descriptor.getResolvableType().asCollection().resolveGeneric();if (elementType == null) {return null;}Map<String, Object> matchingBeans = findAutowireCandidates(beanName, elementType,new MultiElementDescriptor(descriptor));if (matchingBeans.isEmpty()) {return null;}if (autowiredBeanNames != null) {autowiredBeanNames.addAll(matchingBeans.keySet());}TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter());Object result = converter.convertIfNecessary(matchingBeans.values(), type);if (result instanceof List) {if (((List<?>) result).size() > 1) {Comparator<Object> comparator = adaptDependencyComparator(matchingBeans);if (comparator != null) {((List<?>) result).sort(comparator);}}}return result;} else if (Map.class == type) {ResolvableType mapType = descriptor.getResolvableType().asMap();Class<?> keyType = mapType.resolveGeneric(0);if (String.class != keyType) {return null;}Class<?> valueType = mapType.resolveGeneric(1);if (valueType == null) {return null;}Map<String, Object> matchingBeans = findAutowireCandidates(beanName, valueType,new MultiElementDescriptor(descriptor));if (matchingBeans.isEmpty()) {return null;}if (autowiredBeanNames != null) {autowiredBeanNames.addAll(matchingBeans.keySet());}return matchingBeans;} else {return null;}}}2.2 查找Beanpublic class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {protected Map<String, Object> findAutowireCandidates(@Nullable String beanName, Class<?> requiredType, DependencyDescriptor descriptor) {// 通过类型获取指定类型的BeanString[] candidateNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors(this, requiredType, true, descriptor.isEager());Map<String, Object> result = CollectionUtils.newLinkedHashMap(candidateNames.length);// resolvableDependencies 集合中保存了 ， 容器内置的和自定义注册的依赖注入对象//（如：HttpServletRequest对象的注入为该集合内部指定的对象）for (Map.Entry<Class<?>, Object> classObjectEntry : this.resolvableDependencies.entrySet()) {Class<?> autowiringType = classObjectEntry.getKey();if (autowiringType.isAssignableFrom(requiredType)) {Object autowiringValue = https://www.isolves.com/it/cxkf/jiagou/2023-09-14/classObjectEntry.getValue();autowiringValue = AutowireUtils.resolveAutowiringValue(autowiringValue, requiredType);if (requiredType.isInstance(autowiringValue)) {result.put(ObjectUtils.identityToString(autowiringValue), autowiringValue);break;}}}for (String candidate : candidateNames) {// 判断是否自己引用自己if (!isSelfReference(beanName, candidate) && isAutowireCandidate(candidate, descriptor)) {addCandidateEntry(result, candidate, descriptor, requiredType);}}if (result.isEmpty()) {boolean multiple = indicatesMultipleBeans(requiredType);// Consider fallback matches if the first pass failed to find anything...DependencyDescriptor fallbackDescriptor = descriptor.forFallbackMatch();for (String candidate : candidateNames) {if (!isSelfReference(beanName, candidate) && isAutowireCandidate(candidate, fallbackDescriptor) &&(!multiple || getAutowireCandidateResolver().hasQualifier(descriptor))) {addCandidateEntry(result, candidate, descriptor, requiredType);}}if (result.isEmpty() && !multiple) {// Consider self references as a final pass...// but in the case of a dependency collection, not the very same bean itself.for (String candidate : candidateNames) {if (isSelfReference(beanName, candidate) &&(!(descriptor instanceof MultiElementDescriptor) || !beanName.equals(candidate)) &&isAutowireCandidate(candidate, fallbackDescriptor)) {addCandidateEntry(result, candidate, descriptor, requiredType);}}}}return result;}}


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