相对于Bean的创建过程，注入过程显得简单而清晰的多。
注入的过程整体分为两个阶段：
第一个阶段是依据BeanDefition定义的property找到相关的属性值，这个过程中如果定义了autowireByName 或者autowireByType 优先进行这两个定义的查找，然后进行正常匹配，也就是我们定义的<property>，这个部分会覆盖掉autowire的内容。以上所有找到的属性值都会放到一个deepcopy容器里面。
第二个阶段就是把deepcopy容器的值注入到bean中。
1 populateBean 依赖注入的入口
在这个方法中注册了后处理方法，并且完成了autowire定义的属性值的获取。
protected void populateBean(String beanName,RootBeanDefinition mbd,BeanWrapper bw) {
//获得所有的属性集合
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;
// 注册后处理方法
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;
}
//优先设置自动装配
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,newPvs);
}
//从自动装配方法中获得需要注入的属性 如果配置了普通的属性注入 这些值将会在后面被覆盖
pvs = newPvs;
}
boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors();
boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE);
//在这处理普通的依赖注入 会覆盖掉之前自动装配的结果
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,pvs);
}
}
//依赖注入的入口
applyPropertyValues(beanName,pvs);
}
2 autowireByName
根据名字自动注入
protected void autowireByName(
String beanName,AbstractBeanDefinition mbd,BeanWrapper bw,MutablePropertyValues pvs) {
String[] propertyNames = unsatisfiedNonSimpleProperties(mbd,bw);
//遍历自动状态的名字 从当前的容器中寻找对应的Bean，如果能找到，就把这个值放入属性值容器中 用于后面的注入行为
for (String propertyName : propertyNames) {
if (containsBean(propertyName)) {
Object bean = getBean(propertyName);
pvs.add(propertyName,bean);
registerDependentBean(propertyName,beanName);
if (logger.isDebugEnabled()) {
logger.debug("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");
}
}
}
}
3 autowireByType
根据类型自动注入，核心方法是doResolveDependency
protected void autowireByType(
String beanName,MutablePropertyValues pvs) {
TypeConverter converter = getCustomTypeConverter();
if (converter == null) {
converter = bw;
}
Set<String> autowiredBeanNames = new LinkedHashSet<String>(4);
String[] propertyNames = unsatisfiedNonSimpleProperties(mbd,bw);
for (String propertyName : propertyNames) {
try {
PropertyDescriptor pd = bw.getPropertyDescriptor(propertyName);
//Spring规定不能使用Object类型的 自动装配
if (!Object.class.equals(pd.getPropertyType())) {
MethodParameter methodParam = BeanUtils.getWriteMethodParameter(pd);
// Do not allow eager init for type matching in case of a prioritized post-processor.
boolean eager = !PriorityOrdered.class.isAssignableFrom(bw.getWrappedClass());
//构造一个autowirebyType的处理器，用于找到对应的注入的Bean
DependencyDescriptor desc = new AutowireByTypeDependencyDescriptor(methodParam,eager);
// 处理自动装配 找到对应的属性值
Object autowiredArgument = resolveDependency(desc,autowiredBeanNames,converter);
if (autowiredArgument != null) {
pvs.add(propertyName,autowiredArgument);
}
for (String autowiredBeanName : autowiredBeanNames) {
registerDependentBean(autowiredBeanName,beanName);
if (logger.isDebugEnabled()) {
logger.debug("Autowiring by type from bean name '" + beanName + "' via property '" +
propertyName + "' to bean named '" + autowiredBeanName + "'");
}
}
autowiredBeanNames.clear();
}
}
catch (BeansException ex) {
throw new UnsatisfiedDependencyException(mbd.getResourceDescription(),propertyName,ex);
}
}
}
4 doResolveDependency
这个方法处理byType自动注入的值获取过程。分别处理了 array collection（list 和set） map等数组和集合类型的自动注入。对于这个注入过程，所有的集合和Map类型的set注入方法必须定义为接口类型，如果定义为他们的实现类，就无法完成注入
public Object doResolveDependency(DependencyDescriptor descriptor,String beanName,Set<String> autowiredBeanNames,TypeConverter typeConverter) throws BeansException {
Class<?> type = descriptor.getDependencyType();
Object value = getAutowireCandidateResolver().getSuggestedValue(descriptor);
if (value != null) {
if (value instanceof String) {
String strVal = resolveEmbeddedValue((String) value);
BeanDefinition bd = (beanName != null && containsBean(beanName) ? getMergedBeanDefinition(beanName) : null);
value = evaluateBeanDefinitionString(strVal,bd);
}
TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter());
return (descriptor.getField() != null ?
converter.convertIfNecessary(value,type,descriptor.getField()) :
converter.convertIfNecessary(value,descriptor.getMethodParameter()));
}
//对数组类型的自动注入
if (type.isArray()) {
Class<?> componentType = type.getComponentType();
DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor);
targetDesc.increaseNestingLevel();
Map<String,Object> matchingBeans = findAutowireCandidates(beanName,componentType,targetDesc);
if (matchingBeans.isEmpty()) {
if (descriptor.isrequired()) {
raiseNoSuchBeanDefinitionException(componentType,"array of " + componentType.getName(),descriptor);
}
return null;
}
if (autowiredBeanNames != null) {
autowiredBeanNames.addAll(matchingBeans.keySet());
}
TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter());
Object result = converter.convertIfNecessary(matchingBeans.values(),type);
if (getDependencyComparator() != null && result instanceof Object[]) {
Arrays.sort((Object[]) result,adaptDependencyComparator(matchingBeans));
}
return result;
}
//对集合类型的注入 这里的集合对应的set方法必须定义为set list这样的接口类型
// 如果定义为他们的实现类 将不能完成注入
// 对于集合的注入 spring将搜索配置文件中所有定义为集合泛型类型的bean 注入
// 如果没有定义泛型 也不能完成注入
else if (Collection.class.isAssignableFrom(type) && type.isInterface()) {
Class<?> elementType = descriptor.getCollectionType();
if (elementType == null) {
if (descriptor.isrequired()) {
throw new FatalBeanException("No element type declared for collection [" + type.getName() + "]");
}
return null;
}
DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor);
targetDesc.increaseNestingLevel();
Map<String,elementType,targetDesc);
if (matchingBeans.isEmpty()) {
if (descriptor.isrequired()) {
raiseNoSuchBeanDefinitionException(elementType,"collection of " + elementType.getName(),type);
if (getDependencyComparator() != null && result instanceof List) {
Collections.sort((List<?>) result,adaptDependencyComparator(matchingBeans));
}
return result;
}
//Map类型也必须定义为接口类型
else if (Map.class.isAssignableFrom(type) && type.isInterface()) {
Class<?> keyType = descriptor.getMapKeyType();
if (keyType == null || !String.class.isAssignableFrom(keyType)) {
if (descriptor.isrequired()) {
throw new FatalBeanException("Key type [" + keyType + "] of map [" + type.getName() +
"] must be assignable to [java.lang.String]");
}
return null;
}
Class<?> valueType = descriptor.getMapValueType();
if (valueType == null) {
if (descriptor.isrequired()) {
throw new FatalBeanException("No value type declared for map [" + type.getName() + "]");
}
return null;
}
DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor);
targetDesc.increaseNestingLevel();
Map<String,valueType,targetDesc);
if (matchingBeans.isEmpty()) {
if (descriptor.isrequired()) {
raiseNoSuchBeanDefinitionException(valueType,"map with value type " + valueType.getName(),descriptor);
}
return null;
}
if (autowiredBeanNames != null) {
autowiredBeanNames.addAll(matchingBeans.keySet());
}
return matchingBeans;
}
// 对于其他类型
else {
//首先找到所有符合类型定义的Bean
Map<String,descriptor);
//如果没有找到 并且这个属性还是required 抛出异常
if (matchingBeans.isEmpty()) {
if (descriptor.isrequired()) {
raiseNoSuchBeanDefinitionException(type,"",descriptor);
}
return null;
}
//如果结果不唯一 查看有没有定义primary的 如果没有定义 抛出不唯一的异常
if (matchingBeans.size() > 1) {
String primaryBeanName = determineAutowireCandidate(matchingBeans,descriptor);
if (primaryBeanName == null) {
throw new NoUniqueBeanDefinitionException(type,matchingBeans.keySet());
}
if (autowiredBeanNames != null) {
autowiredBeanNames.add(primaryBeanName);
}
return matchingBeans.get(primaryBeanName);
}
// 对于唯一的结果 放入属性集合
Map.Entry<String,Object> entry = matchingBeans.entrySet().iterator().next();
if (autowiredBeanNames != null) {
autowiredBeanNames.add(entry.getKey());
}
return entry.getValue();
}
}
5 applyPropertyValues 获取属性值的过程
这个方法是获取属性值的主要方法 这里主要利用了BeanDefinitionValueResolver进行了属性值转换，将属性值与BeanDefition中定义的需要的值连接在一起，放入deepcopy容器中
/**
* Apply the given property values,resolving any runtime references
* to other beans in this bean factory. Must use deep copy,so we
* don't permanently modify this property.
* @param beanName the bean name passed for better exception information
* @param mbd the merged bean definition
* @param bw the BeanWrapper wrapping the target object
* @param pvs the new property values
*/
protected void applyPropertyValues(String beanName,BeanDefinition mbd,PropertyValues pvs) {
if (pvs == null || pvs.isEmpty()) {
return;
}
//
MutablePropertyValues mpvs = null;
//原始属性值
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(),"Error setting property values",ex);
}
}
original = mpvs.getPropertyValueList();
}
else {
original = Arrays.asList(pvs.getPropertyValues());
}
TypeConverter converter = getCustomTypeConverter();
if (converter == null) {
converter = bw;
}
//属性值转换器 需要将注入的属性值转换为beanDefition定义的属性值
BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this,converter);
// 建立一个属性值的深拷贝 保存所有转换过的属性值
List<PropertyValue> deepCopy = new ArrayList<PropertyValue>(original.size());
boolean resolveNecessary = false;
for (PropertyValue pv : original) {
//如果已经处理过，直接放入list中
if (pv.isConverted()) {
deepCopy.add(pv);
}
else {
String propertyName = pv.getName();
Object originalValue = pv.getValue();
//第一次转换
Object resolvedValue = valueResolver.resolveValueIfNecessary(pv,originalValue);
Object convertedValue = resolvedValue;
boolean convertible = bw.isWritableProperty(propertyName) &&
!PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName);
if (convertible) {
//第二次转换
convertedValue = convertForProperty(resolvedValue,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 {
//将转换过的值注入到到Bean中
bw.setPropertyValues(new MutablePropertyValues(deepCopy));
}
catch (BeansException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(),ex);
}
}
6 resolveValueIfNecessary属性值转换器
/*
Given a PropertyValue,return a value,resolving any references to other beans in the factory if necessary. The value could be:
A BeanDefinition,which leads to the creation of a corresponding new bean instance. Singleton flags and names of such "inner beans" are always ignored: Inner beans are anonymous prototypes.
A RuntimeBeanReference,which must be resolved.
A ManagedList. This is a special collection that may contain RuntimeBeanReferences or Collections that will need to be resolved.
A ManagedSet. May also contain RuntimeBeanReferences or Collections that will need to be resolved.
A ManagedMap. In this case the value may be a RuntimeBeanReference or Collection that will need to be resolved.
An ordinary object or null,in which case it's left alone.
*/
public Object resolveValueIfNecessary(Object argName,Object value) {
/**
处理最常见的一类注入 注入的对象是容器中的另一个bean
这里成为runtime reference
*/
if (value instanceof RuntimeBeanReference) {
RuntimeBeanReference ref = (RuntimeBeanReference) value;
return resolveReference(argName,ref);
}
else if (value instanceof RuntimeBeanNameReference) {
String refName = ((RuntimeBeanNameReference) value).getBeanName();
refName = String.valueOf(doEvaluate(refName));
if (!this.beanfactory.containsBean(refName)) {
throw new BeanDefinitionStoreException(
"Invalid bean name '" + refName + "' in bean reference for " + argName);
}
return refName;
}
/**
下面两个都是在处理嵌套定义的bean
*/
else if (value instanceof BeanDefinitionHolder) {
// Resolve BeanDefinitionHolder: contains BeanDefinition with name and aliases.
//这里处理的是正式定义的bean 有id
BeanDefinitionHolder bdHolder = (BeanDefinitionHolder) value;
return resolveInnerBean(argName,bdHolder.getBeanName(),bdHolder.getBeanDefinition());
}
else if (value instanceof BeanDefinition) {
// Resolve plain BeanDefinition,without contained name: use dummy name.
//这里处理的是匿名的bean
BeanDefinition bd = (BeanDefinition) value;
String innerBeanName = "(inner bean)" + beanfactoryUtils.GENERATED_BEAN_NAME_SEPARATOR +
ObjectUtils.getIdentityHexString(bd);
return resolveInnerBean(argName,innerBeanName,bd);
}
//数组的处理
else if (value instanceof ManagedArray) {
// May need to resolve contained runtime references.
ManagedArray array = (ManagedArray) value;
Class<?> elementType = array.resolvedElementType;
if (elementType == null) {
String elementTypeName = array.getElementTypeName();
if (StringUtils.hasText(elementTypeName)) {
try {
elementType = ClassUtils.forName(elementTypeName,this.beanfactory.getBeanClassLoader());
array.resolvedElementType = elementType;
}
catch (Throwable ex) {
// Improve the message by showing the context.
throw new BeanCreationException(
this.beanDefinition.getResourceDescription(),this.beanName,"Error resolving array type for " + argName,ex);
}
}
else {
elementType = Object.class;
}
}
return resolveManagedArray(argName,(List<?>) value,elementType);
}
//对list的处理
else if (value instanceof ManagedList) {
// May need to resolve contained runtime references.
return resolveManagedList(argName,(List<?>) value);
}
//对set的处理
else if (value instanceof ManagedSet) {
// May need to resolve contained runtime references.
return resolveManagedSet(argName,(Set<?>) value);
}
//对map的处理
else if (value instanceof ManagedMap) {
// May need to resolve contained runtime references.
return resolveManagedMap(argName,(Map<?,?>) value);
}
//对property集合的处理 不需要转换 直接放入copy中
else if (value instanceof ManagedProperties) {
Properties original = (Properties) value;
Properties copy = new Properties();
for (Map.Entry<Object,Object> propEntry : original.entrySet()) {
Object propKey = propEntry.getKey();
Object propValue = propEntry.getValue();
if (propKey instanceof TypedStringValue) {
propKey = evaluate((TypedStringValue) propKey);
}
if (propValue instanceof TypedStringValue) {
propValue = evaluate((TypedStringValue) propValue);
}
copy.put(propKey,propValue);
}
return copy;
}
/**
对于其他常量的处理 String int boolean 等类型
对他们的处理不需要借助于额外的转换器 仅需调用evaluate生成对应值即可
*/
//对String类型的处理
else if (value instanceof TypedStringValue) {
// Convert value to target type here.
TypedStringValue typedStringValue = (TypedStringValue) value;
Object valueObject = evaluate(typedStringValue);
try {
Class<?> resolvedTargetType = resolveTargetType(typedStringValue);
if (resolvedTargetType != null) {
return this.typeConverter.convertIfNecessary(valueObject,resolvedTargetType);
}
else {
return valueObject;
}
}
catch (Throwable ex) {
// Improve the message by showing the context.
throw new BeanCreationException(
this.beanDefinition.getResourceDescription(),"Error converting typed String value for " + argName,ex);
}
}
//对于其他值的处理
else {
return evaluate(value);
}
}
7 setPropertyValue 注入属性值的过程
这里主要是通过反射将前面得到的属性值注入到Bean中
private void setPropertyValue(PropertyTokenHolder tokens,PropertyValue pv) throws BeansException {
String propertyName = tokens.canonicalName;
String actualName = tokens.actualName;
/** 对 array list map 这三种类型的处理
这三种类型的注入并不是通过set方法的反射完成
而是直接通过Java的对这些类的反射方法 直接修改对应属性值
*/
if (tokens.keys != null) {
//下面十几行的作用是在找到集合或者数组的属性名
// 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,getterTokens.keys,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(),"Cannot access indexed value in property referenced " +
"in indexed property path '" + propertyName + "': returned null");
}
}
//对于数组的注入
if (propValue.getClass().isArray()) {
PropertyDescriptor pd = getCachedIntrospectionResults().getPropertyDescriptor(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,TypeDescriptor.nested(property(pd),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,newArray,length);
setPropertyValue(actualName,newArray);
propValue = getPropertyValue(actualName);
}
//通过Java 反射包下面Array类进行对应的值的修改
Array.set(propValue,arrayIndex,convertedValue);
}
catch (IndexOutOfBoundsException ex) {
throw new InvalidPropertyException(getRootClass(),"Invalid array index in property path '" + propertyName + "'",ex);
}
}
//对list进行注入
else if (propValue instanceof List) {
PropertyDescriptor pd = getCachedIntrospectionResults().getPropertyDescriptor(actualName);
Class<?> requiredType = GenericCollectionTypeResolver.getCollectionReturnType(
pd.getReadMethod(),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,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(),"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 {
//直接对获取到的list进行赋值
list.set(index,convertedValue);
}
catch (IndexOutOfBoundsException ex) {
throw new InvalidPropertyException(getRootClass(),"Invalid list index in property path '" + propertyName + "'",ex);
}
}
}
//对map进行注入
else if (propValue instanceof Map) {
PropertyDescriptor pd = getCachedIntrospectionResults().getPropertyDescriptor(actualName);
Class<?> mapKeyType = GenericCollectionTypeResolver.getMapKeyReturnType(
pd.getReadMethod(),tokens.keys.length);
Class<?> mapValueType = GenericCollectionTypeResolver.getMapValueReturnType(
pd.getReadMethod(),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,mapValueType,tokens.keys.length));
//直接对获取到的map进行赋值
map.put(convertedMapKey,convertedMapValue);
}
else {
throw new InvalidPropertyException(getRootClass(),"Property referenced in indexed property path '" + propertyName +
"' is neither an array nor a List nor a Map; returned value was [" + pv.getValue() + "]");
}
}
//对于非集合类型的注入
else {
PropertyDescriptor pd = pv.resolvedDescriptor;
if (pd == null || !pd.getWriteMethod().getDeclaringClass().isInstance(this.object)) {
pd = getCachedIntrospectionResults().getPropertyDescriptor(actualName);
if (pd == null || pd.getWriteMethod() == null) {
if (pv.isOptional()) {
logger.debug("Ignoring optional value for property '" + actualName +
"' - property not found on bean class [" + getRootClass().getName() + "]");
return;
}
else {
PropertyMatches matches = PropertyMatches.forProperty(propertyName,getRootClass());
throw new NotWritablePropertyException(
getRootClass(),matches.buildErrorMessage(),matches.getPossibleMatches());
}
}
pv.getOriginalPropertyValue().resolvedDescriptor = pd;
}
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() && pd.getReadMethod() != null) {
//通过反射获取对应的set方法
final Method readMethod = pd.getReadMethod();
if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers()) &&
!readMethod.isAccessible()) {
if (System.getSecurityManager()!= null) {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
@Override
public Object run() {
//提升方法的访问权限
readMethod.setAccessible(true);
return null;
}
});
}
else {
readMethod.setAccessible(true);
}
}
try {
if (System.getSecurityManager() != null) {
oldValue = AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() {
@Override
public Object run() throws Exception {
//通过反射驱动set方法注入
return readMethod.invoke(object);
}
},acc);
}
else {
oldValue = readMethod.invoke(object);
}
}
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,originalValue,new TypeDescriptor(property(pd)));
}
pv.getOriginalPropertyValue().conversionNecessary = (valueToApply != originalValue);
}
final Method writeMethod = (pd instanceof GenericTypeAwarePropertyDescriptor ?
((GenericTypeAwarePropertyDescriptor) pd).getWriteMethodForActualAccess() :
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(this.object,value);
}
}
catch (TypeMismatchException ex) {
throw ex;
}
catch (InvocationTargetException ex) {
PropertyChangeEvent propertyChangeEvent =
new PropertyChangeEvent(this.rootObject,pv.getValue());
if (ex.getTargetException() instanceof ClassCastException) {
throw new TypeMismatchException(propertyChangeEvent,pd.getPropertyType(),ex.getTargetException());
}
else {
throw new MethodInvocationException(propertyChangeEvent,ex.getTargetException());
}
}
catch (Exception ex) {
PropertyChangeEvent pce =
new PropertyChangeEvent(this.rootObject,pv.getValue());
throw new MethodInvocationException(pce,ex);
}
}
}
8 getReadMethod
public synchronized Method getReadMethod() {
Method readMethod = getReadMethod0();
if (readMethod == null) {
Class cls = getClass0();
if (cls == null || (readMethodName == null && readMethodRef == null)) {
// The read method was explicitly set to null.
return null;
}
if (readMethodName == null) {
Class type = getPropertyType0();
if (type == boolean.class || type == null) {
readMethodName = "is" + getBaseName();//boolean类型 方法使用is开头
} else {
readMethodName = "get" + getBaseName();//get方法
}
}
// Since there can be multiple write methods but only one getter
// method,find the getter method first so that you know what the
// property type is. For booleans,there can be "is" and "get"
// methods. If an "is" method exists,this is the official
// reader method so look for this one first.
readMethod = Introspector.findMethod(cls,readMethodName,0);
if (readMethod == null) {
readMethodName = "get" + getBaseName();
readMethod = Introspector.findMethod(cls,0);
}
try {
setReadMethod(readMethod);
} catch (IntrospectionException ex) {
// fall
}
}
return readMethod;
} 原文链接：https://www.f2er.com/javaschema/284567.html