本篇文章主要就是分析Spring源码剖析-Bean的实例化-属性注入的相关知识，通过本文学习AbstractAutowireCapablebeanfactory#populateBean 方法的主要功能就是属性填充，感兴趣的朋友跟随小编一起看看吧
前言
这一章节我们来讨论创建Bean过程中的属性注入，在Spring的IOC容器启动过程中，会把定义的Bean封装成BeanDeFinition注册到一个ConcurrentHashMap中，Bean注册完成后，就会对单利的且lazy-init=false 的Bean进行实例化。创建Bean的代码在 AbstractAutowireCapablebeanfactory#doCreateBean 中，当Bean创建成功之后，会调用AbstractAutowireCapablebeanfactory#populateBean 方法进行属性注入。本篇文章主要就是分析该方法是如何实现Bean的属性注入的。
属性注入：AbstractAutowireCapablebeanfactory#populateBean
AbstractAutowireCapablebeanfactory#populateBean 方法的主要功能就是属性填充，源码如下
//使用 bean 定义中的属性值填充给定 BeanWrapper 中的 bean 实例。 @SuppressWarnings("deprecation") // for postProcesspropertyValues protected void populateBean(String beanName, RootBeanDeFinition mbd, @Nullable BeanWrapper bw) { if (bw == null) { //判断是否有property属性 if (mbd.hasPropertyValues()) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance"); } else { //没有任何属性可以填充 // 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. //让 InstantiationAwareBeanPostProcessors 也在属性注入之前改变Bean的状态 if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { return; } } } } //从 RootBeanDeFinition 获取所有的PropertyValues PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null); int resolvedAutowireMode = mbd.getResolvedAutowireMode(); //根据名字获取根据type注入 if (resolvedAutowireMode == AUTOWIRE_BY_NAME || resolvedAutowireMode == AUTOWIRE_BY_TYPE) { MutablePropertyValues newPvs = new MutablePropertyValues(pvs); // Add property values based on autowire by name if applicable. //如果适用，根据名称添加基于自动装配的属性值。 if (resolvedAutowireMode == AUTOWIRE_BY_NAME) { autowireByName(beanName, mbd, bw, newPvs); } // Add property values based on autowire by type if applicable. //如果适用，根据类型添加基于自动装配的属性值 if (resolvedAutowireMode == AUTOWIRE_BY_TYPE) { autowireByType(beanName, mbd, bw, newPvs); } pvs = newPvs; } //后置处理器是否已经注册,初始化好了 boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors(); //是否要检查依赖，默认false boolean needsDepCheck = (mbd.getDependencyCheck() != AbstractBeanDeFinition.DEPENDENCY_CHECK_NONE); PropertyDescriptor[] filteredPds = null; if (hasInstAwareBpps) { if (pvs == null) { pvs = mbd.getPropertyValues(); } //获取后置处理器 for (BeanPostProcessor bp : getBeanPostProcessors()) { //如果是Bean实例化后置处理器 if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; // PropertyValues pvsToUse = ibp.postProcessproperties(pvs, bw.getWrappedInstance(), beanName); if (pvsToUse == null) { if (filteredPds == null) { filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); } //对需要依赖检查的属性进行后置处理 pvsToUse = ibp.postProcesspropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName); if (pvsToUse == null) { return; } } pvs = pvsToUse; } } } if (needsDepCheck) { if (filteredPds == null) { filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); } checkDependencies(beanName, mbd, filteredPds, pvs); } if (pvs != null) { //依赖注入入口，讲属性应用到Bean中 applyPropertyValues(beanName, mbd, bw, pvs); } }
autowireByName : 根据属性名进行注入
autowireByType：根据类型注入Bean
InstantiationAwareBeanPostProcessor.postProcesspropertyValues :该方法是在工厂将给定的属性值应用于给定的 bean 之前对给定的属性值进行处理，比如：requiredAnnotationBeanPostProcessor类中对属性的验证。
applyPropertyValues：属性的填充
autowireByName是根据名字注入，源码如下
protected void autowireByName( String beanName, AbstractBeanDeFinition mbd, BeanWrapper bw, MutablePropertyValues pvs) { //寻找BeanWrapper中需要依赖的属性 String[] propertyNames = unsatisfiednonSimpleProperties(mbd, bw); for (String propertyName : propertyNames) { if (containsBean(propertyName)) { //递归实例化的Bean Object bean = getBean(propertyName); pvs.add(propertyName, bean); //注册依赖的Bean，加入 dependentBeanMap 中 registerDependentBean(propertyName, beanName); if (logger.isTraceEnabled()) { logger.trace("Added autowiring by name from bean name '" + beanName + "' via property '" + propertyName + "' to bean named '" + propertyName + "'"); } } else { if (logger.isTraceEnabled()) { logger.trace("Not autowiring property '" + propertyName + "' of bean '" + beanName + "' by name: no matching bean found"); } } } }
这个方法很简单，就是先找到依赖的Bean，递归初始化，然后加入 pvs中
//定义“按类型自动装配”（按类型的 bean 属性）行为的抽象方法 protected void autowireByType( String beanName, AbstractBeanDeFinition mbd, BeanWrapper bw, MutablePropertyValues pvs) { //类型转换器 TypeConverter converter = getCustomTypeConverter(); if (converter == null) { converter = bw; } Set autowiredBeanNames = new LinkedHashSet(4); //找到需要注入的属性 String[] propertyNames = unsatisfiednonSimpleProperties(mbd, bw); for (String propertyName : propertyNames) { try { //属性描述 PropertyDescriptor pd = bw.getPropertyDescriptor(propertyName); // Don't try autowiring by type for type Object: never makes sense, // even if it technically is a unsatisfied, non-simple property. if (Object.class != pd.getPropertyType()) { //获取对象的set方法 MethodParameter methodParam = BeanUtils.getWriteMethodParameter(pd); // Do not allow eager init for type matching in case of a prioritized post-processor. boolean eager = !(bw.getWrappedInstance() instanceof PriorityOrdered); //依赖描述 DependencyDescriptor desc = new AutowireByTypeDependencyDescriptor(methodParam, eager); //【重要】得到依赖的属性的值，存储到 autowiredBeanNames 集合中 //提供了对集合如：@Autowired private List as; 支持，根据类型走到所有的Bean注入其中 Object autowiredArgument = resolveDependency(desc, beanName, autowiredBeanNames, converter); if (autowiredArgument != null) { //添加到pvs pvs.add(propertyName, autowiredArgument); } for (String autowiredBeanName : autowiredBeanNames) { //注入依赖的Bean registerDependentBean(autowiredBeanName, beanName); if (logger.isTraceEnabled()) { logger.trace("Autowiring by type from bean name '" + beanName + "' via property '" + propertyName + "' to bean named '" + autowiredBeanName + "'"); } } //清理掉依赖 autowiredBeanNames.clear(); } } catch (BeansException ex) { throw new UnsatisfiedDependencyException(mbd.getResourceDescription(), beanName, propertyName, ex); } } }
看到这，我们大概清楚了，其实在populateBean 方法中会先从RootBeanDeFinition 中获取 Bean的属性(PropertyValues)，同时也会根据RootBeanDeFinition的autowireMode自动注入模式来根据name或者type寻主Bean的依赖的属性。
根据类型注入和根据名字注入都是先从BeanWrapper 中找到Bean的依赖的属性，然后根据属性类型找到匹配的Bean，实现依赖注入。还提供了对集合如：@Autowired private List as; 集合注入的支持。
属性寻找好之后都会封装成 PropertyValues，然后传给applyPropertyValues应用到Bean身上。
AbstractAutowireCapablebeanfactory#applyPropertyValues
我们可以认为前面的代码是在为当前Bean寻找依赖的的属性，封装到 PropertyValues中，在applyPropertyValues中才是把属性应用到当前Bean。
//处理对象之间的引用，使用深拷贝 protected void applyPropertyValues(String beanName, BeanDeFinition mbd, BeanWrapper bw, PropertyValues pvs) { if (pvs.isEmpty()) { return; } if (System.getSecurityManager() != null && bw instanceof BeanWrapperImpl) { ((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext()); } MutablePropertyValues mpvs = null; List original; if (pvs instanceof MutablePropertyValues) { mpvs = (MutablePropertyValues) pvs; //判断mpvs中的值是否已经转成了对应的类型，已经转了就可以直接设置值到 BeanWrapper了 if (mpvs.isConverted()) { // Shortcut: use the pre-converted values as-is. try { //为实例化对象设置属性 bw.setPropertyValues(mpvs); return; } catch (BeansException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Error setting property values", ex); } } //获取属性值的原始类型 original = mpvs.getPropertyValueList(); } else { //如果类型不是MutablePropertyValues ， 就使用原生属性获取方法 original = Arrays.asList(pvs.getPropertyValues()); } //获取用户自定义的型转换器 TypeConverter converter = getCustomTypeConverter(); if (converter == null) { converter = bw; } //解析器：用于 bean 工厂实现的 Helper 类，将 bean 定义对象中包含的值，解析为应用于目标 bean 实例的实际值。 BeanDeFinitionValueResolver valueResolver = new BeanDeFinitionValueResolver(this, beanName, mbd, converter); // Create a deep copy, resolving any references for values. //存放类型转换过的属性，把Bean的属性解析值新建拷贝，把拷贝的数据注入到对象 List deepcopy = new ArrayList(original.size()); boolean resolveNecessary = false; //类型转换，把属性转换为对应的类型 for (PropertyValue pv : original) { if (pv.isConverted()) { //属性值不需要转 deepcopy.add(pv); } else { //属性名 String propertyName = pv.getName(); //原始属性值，它的类型是一个 如： RuntimeBeanReference 引用类型 Object originalValue = pv.getValue(); //转换属性值，将引用转换为 IOC 容器中实例化对象引用 OtherBean Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue); Object convertedValue = resolvedValue; boolean convertible = bw.isWritableProperty(propertyName) && !PropertyAccessorUtils.isnestedOrIndexedProperty(propertyName); if (convertible) { //使用用户自定义的转换器转换 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) { //设置转换之后的值到PV ，把依赖的Bean设置给PropertyValue 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; //转换好的依赖的属性最终放到一个ArrayList中 deepcopy.add(new PropertyValue(pv, convertedValue)); } } } if (mpvs != null && !resolveNecessary) { mpvs.setConverted(); } // Set our (possibly massaged) deep copy. try { //把解析好的属性 设置到 BeanWrapper 中 bw.setPropertyValues(new MutablePropertyValues(deepcopy)); } catch (BeansException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Error setting property values", ex); } }
这里主要进行属性转换，然后应用到Bean身上，这里的属性转换比如: 在BeanDeFinition中属性可能是用字符串类型来描述的，需要把属性转成真实的原始属性类型。
首先判断属性是否需要转换类型，如果不需要转直接应用于Bean。比如： 这种属性值其实是个字符串“otherBean” ，需要解析成容器中的OtherBean实例的引用。
如果属性值需要类型转换，比如：属性值是容器中的另外一个Bean，则需要根据属性值解析出引用的对象然后注入到对象的属性上，应用到Bean。
通过 BeanDeFinitionValueResolver 类中的 resolveValueIfNecessary()方法中进行属性值的解析， 对属性值的注入是通过 bw.setPropertyValues()方法完成
解析： BeanDeFinitionValueResolver#resolveValueIfNecessary
给定一个 PropertyValue根据属性值进行类型解析，必要时解析对工厂中其他 bean 的引用
@Nullable public Object resolveValueIfNecessary(Object argName, @Nullable Object value) { // We must check each value to see whether it requires a runtime reference // to another bean to be resolved. //对属性值是引用类型的解析 if (value instanceof RuntimeBeanReference) { //比如： { if (propKey instanceof TypedStringValue) { propKey = evaluate((TypedStringValue) propKey); } if (propValue instanceof TypedStringValue) { propValue = evaluate((TypedStringValue) propValue); } if (propKey == null || propValue == null) { throw new BeanCreationException( this.beanDeFinition.getResourceDescription(), this.beanName, "Error converting Properties key/value pair for " + argName + ": resolved to null"); } copy.put(propKey, propValue); }); return copy; } //解析字符串类型的属性值 else if (value instanceof TypedStringValue) { // Convert value to target type here. TypedStringValue typedStringValue = (TypedStringValue) value; Object valueObject = evaluate(typedStringValue); try { //目标类型 Class> resolvedtargettype = resolvetargettype(typedStringValue); if (resolvedtargettype != null) { //目标类型进行解析 return this.typeConverter.convertIfNecessary(valueObject, resolvedtargettype); } else { //类型没获取到，就返回Object类型 return valueObject; } } catch (Throwable ex) { // Improve the message by showing the context. throw new BeanCreationException( this.beanDeFinition.getResourceDescription(), this.beanName, "Error converting typed String value for " + argName, ex); } } else if (value instanceof NullBean) { return null; } else { return evaluate(value); } }
这个方法中就是根据属性的值的类型进行解析，如：String，Array,List,Set,Map的类型，比较复杂的就是属性值依赖的是一个Bean，那么就需要根据依赖的Bean的名字找到容器中的Bean的实例，查找如下：
/** * Resolve a reference to another bean in the factory. */ //关联对象的解析 @Nullable private Object resolveReference(Object argName, RuntimeBeanReference ref) { try { Object bean; //引用对象的名称 String refName = ref.getBeanName(); refName = String.valueOf(doEvaluate(refName)); //如果对象在父容器中，从父容器获取 if (ref.isToParent()) { if (this.beanfactory.getParentbeanfactory() == null) { throw new BeanCreationException( this.beanDeFinition.getResourceDescription(), this.beanName, "Can't resolve reference to bean '" + refName + "' in parent factory: no parent factory available"); } //如果对象在父容器中，从父容器获取 bean = this.beanfactory.getParentbeanfactory().getBean(refName); } else { //[重要]根据依赖的Bean的名字，从当前容器中获取Bean bean = this.beanfactory.getBean(refName); //把依赖的Bean的实例和当前对象建议依赖关系，使用 dependentBeanMap 去维护关系 this.beanfactory.registerDependentBean(refName, this.beanName); } if (bean instanceof NullBean) { bean = null; } return bean; } catch (BeansException ex) { throw new BeanCreationException( this.beanDeFinition.getResourceDescription(), this.beanName, "Cannot resolve reference to bean '" + ref.getBeanName() + "' while setting " + argName, ex); } } * For each element in the managed array, resolve reference if necessary. */ //解析数组 private Object resolveManagedArray(Object argName, List> ml, Class> elementType) { Object resolved = Array.newInstance(elementType, ml.size()); for (int i = 0; i resolveManagedList(Object argName, List> ml) { List resolved = new ArrayList(ml.size()); for (int i = 0; i resolveManagedSet(Object argName, Set> ms) { Set resolved = new LinkedHashSet(ms.size()); int i = 0; for (Object m : ms) { resolved.add(resolveValueIfNecessary(new KeyedArgName(argName, i), m)); i++; } return resolved; } /** * For each element in the managed map, resolve reference if necessary. */ //解析Map private Map, ?> resolveManagedMap(Object argName, Map, ?> mm) { Map resolved = new LinkedHashMap(mm.size()); mm.forEach((key, value) -> { Object resolvedKey = resolveValueIfNecessary(argName, key); Object resolvedValue = resolveValueIfNecessary(new KeyedArgName(argName, key), value); resolved.put(resolvedKey, resolvedValue); }); return resolved; }
属性值解析完成之后 是封装成一个 MutablePropertyValues，通过 BeanWrapperImpl.setPropertyValues()方法完成值的注入，BeanWrapperImpl中注入方法又是由AbstractPropertyAccessor#setPropertyValue(java.lang.String, java.lang.Object)去完成。
AbstractPropertyAccessor#setPropertyValue
@Override public void setPropertyValues(PropertyValues pvs, boolean ignoreUnkNown, boolean ignoreInvalid) throws BeansException { List propertyAccessExceptions = null; //拿到所有的属性列表 List propertyValues = (pvs instanceof MutablePropertyValues ? ((MutablePropertyValues) pvs).getPropertyValueList() : Arrays.asList(pvs.getPropertyValues())); for (PropertyValue pv : propertyValues) { try { // This method may throw any BeansException, which won't be caught // here, if there is a critical failure such as no matching field. // We can attempt to deal only with less serIoUs exceptions. //设置属性值 setPropertyValue(pv); } ...省略... @Override public void setPropertyValue(String propertyName, @Nullable Object value) throws BeansException { //属性访问器 AbstractnestablePropertyAccessor nestedPa; try { nestedPa = getPropertyAccessorForPropertyPath(propertyName); } catch (NotReadablePropertyException ex) { throw new NotWritablePropertyException(getRootClass(), this.nestedpath + propertyName, "nested property in path '" + propertyName + "' does not exist", ex); } //属性助手 PropertyTokenHolder tokens = getPropertyNametokens(getFinalPath(nestedPa, propertyName)); //通过属性访问器为属性设置值 nestedPa.setPropertyValue(tokens, new PropertyValue(propertyName, value)); }
这里看到，属性的注入交给了 AbstractnestablePropertyAccessor 属性访问器去完成
protected void setPropertyValue(PropertyTokenHolder tokens, PropertyValue pv) throws BeansException { if (tokens.keys != null) { processKeyedProperty(tokens, pv); } else { //走这里 processLocalProperty(tokens, pv); } } private void processLocalProperty(PropertyTokenHolder tokens, PropertyValue pv) { //属性处理器 PropertyHandler ph = getLocalPropertyHandler(tokens.actualName); if (ph == null || !ph.isWritable()) { if (pv.isOptional()) { if (logger.isDebugEnabled()) { logger.debug("Ignoring optional value for property '" + tokens.actualName + "' - property not found on bean class [" + getRootClass().getName() + "]"); } return; } else { throw createNotWritablePropertyException(tokens.canonicalName); } } Object oldValue = null; try { //原生值 Object originalValue = pv.getValue(); Object valuetoApply = originalValue; ...省略... //这是重点，通过 PropertyHandler 把属性值设置给对象 ph.setValue(valuetoApply); } catch (TypeMismatchException ex) { throw ex; }
这里的属性值通过 PropertyHandler去设置
@Override public void setValue(@Nullable Object value) throws Exception { //得到属性的set方法 Method writeMethod = (this.pd instanceof GenericTypeAwarePropertyDescriptor ? ((GenericTypeAwarePropertyDescriptor) this.pd).getWriteMethodForActualAccess() : this.pd.getWriteMethod()); if (System.getSecurityManager() != null) { AccessController.doPrivileged((PrivilegedAction) () -> { ReflectionUtils.makeAccessible(writeMethod); return null; }); try { AccessController.doPrivileged((PrivilegedExceptionAction) () -> writeMethod.invoke(getWrappedInstance(), value), acc); } catch (PrivilegedActionException ex) { throw ex.getException(); } } else { //设置访问权限 ReflectionUtils.makeAccessible(writeMethod); //调用set方法把属性值设置进去 writeMethod.invoke(getWrappedInstance(), value); } }
这里就是得到属性的set方法，然后调用set方法把值注入进去。
构造器注入参数
在之前分析Bean的创建的时候我们就说到，在 AbstractAutowireCapablebeanfactory#createBeanInstance 中会通过反射获取到Bean的构造器，如果是有参构造就会走autowireConstructor 方法，通过有参构造创建实例
protected BeanWrapper createBeanInstance(String beanName, RootBeanDeFinition mbd, @Nullable Object[] args) { // Make sure bean class is actually resolved at this point. Class> beanClass = resolveBeanClass(mbd, beanName); ...省略... // Need to determine the constructor... Constructor>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName); if (ctors != null || mbd.getResolvedAutowireMode() == RootBeanDeFinition.AUTOWIRE_CONSTRUCTOR || mbd.hasconstructorargumentValues() || !ObjectUtils.isEmpty(args)) { //【重要】构造器注入参数 return autowireConstructor(beanName, mbd, ctors, args); } // No special handling: simply use no-arg constructor. return instantiateBean(beanName, mbd); }
在autowireConstructor方法中会通过 ConstructorResolver 对构造器参数进行解析
protected BeanWrapper autowireConstructor( String beanName, RootBeanDeFinition mbd, @Nullable Constructor>[] ctors, @Nullable Object[] explicitArgs) { //构造器解析器，注入 return new ConstructorResolver(this).autowireConstructor(beanName, mbd, ctors, explicitArgs); } public BeanWrapper autowireConstructor(final String beanName, final RootBeanDeFinition mbd, @Nullable Constructor>[] chosenCtors, @Nullable final Object[] explicitArgs) { ...省略... else { //得到构造器参数 constructorargumentValues cargs = mbd.getconstructorargumentValues(); //得到构造器参数值 resolvedValues = new constructorargumentValues(); //解析参数值【重要】 minNrOfArgs = resolveconstructorarguments(beanName, mbd, bw, cargs, resolvedValues); } ...省略... try { //实例化策略 final InstantiationStrategy strategy = beanfactory.getInstantiationStrategy(); Object beanInstance; if (System.getSecurityManager() != null) { final Constructor> ctorToUse = constructorToUse; final Object[] argumentsToUse = argsToUse; beanInstance = AccessController.doPrivileged((PrivilegedAction) () -> strategy.instantiate(mbd, beanName, beanfactory, ctorToUse, argumentsToUse), beanfactory.getAccessControlContext()); } else { //实例化对象，根据有参构造器，使用反射创建实例 beanInstance = strategy.instantiate(mbd, beanName, this.beanfactory, constructorToUse, argsToUse); } bw.setBeanInstance(beanInstance); return bw; }
resolveconstructorarguments 方法中又通过 BeanDeFinitionValueResolver来解析属性值，有参数的值了，就会走反射，根据有参构造器创建实例返回。
private int resolveconstructorarguments(String beanName, RootBeanDeFinition mbd, BeanWrapper bw, constructorargumentValues cargs, constructorargumentValues resolvedValues) { TypeConverter customConverter = this.beanfactory.getCustomTypeConverter(); TypeConverter converter = (customConverter != null ? customConverter : bw); //属性值的解析器 BeanDeFinitionValueResolver valueResolver = new BeanDeFinitionValueResolver(this.beanfactory, beanName, mbd, converter); ...省略... for (constructorargumentValues.ValueHolder valueHolder : cargs.getGenericArgumentValues()) { if (valueHolder.isConverted()) { resolvedValues.addGenericArgumentValue(valueHolder); } else { //为构造器参数值做解析，这里和之前分析的set注入的属性值解析就一样了 Object resolvedValue = valueResolver.resolveValueIfNecessary("constructor argument", valueHolder.getValue()); constructorargumentValues.ValueHolder resolvedValueHolder = new constructorargumentValues.ValueHolder( resolvedValue, valueHolder.getType(), valueHolder.getName()); resolvedValueHolder.setSource(valueHolder); resolvedValues.addGenericArgumentValue(resolvedValueHolder); } } return minNrOfArgs; }
因为之前 resolveValueIfNecessary方法已经分析过了，这里就不多说了。
总结
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