Spring Boot如何处理@Resource示例分析
作者：子瞻
这篇文章主要为大家介绍了Spring Boot如何处理@Resource示例分析，有需要的朋友可以借鉴参考下，希望能够有所帮助，祝大家多多进步，早日升职加薪
先造一个测试用例
public class TransactionServiceTest {
@Resource
private IQrcodeAdScheduleService qrcodeAdScheduleService;
}启动Spring Boot调用栈信息
图1
解析@Resource对应的bean信息
由上图可知，在创建完bean实例后，通过applyMergedBeanDefinitionPostProcessors()修改beanDefinition结构(针对这种场景可以理解为解析@Resource对应的bean信息)
protected void applyMergedBeanDefinitionPostProcessors(RootBeanDefinition mbd, Class<?> beanType, String beanName) {
for (BeanPostProcessor bp : getBeanPostProcessors()) {
if (bp instanceof MergedBeanDefinitionPostProcessor) {
MergedBeanDefinitionPostProcessor bdp = (MergedBeanDefinitionPostProcessor) bp;
//执行CommonAnnotationBeanPostProcessor类postProcessMergedBeanDefinition()
bdp.postProcessMergedBeanDefinition(mbd, beanType, beanName);
}
}
}
图2
CommonAnnotationBeanPostProcessor
有图2可知，处理@Resource的PostProcessor是“CommonAnnotationBeanPostProcessor”，然后看一下CommonAnnotationBeanPostProcessor的部分细节：
private InjectionMetadata buildResourceMetadata(final Class<?> clazz) {
LinkedList<InjectionMetadata.InjectedElement> elements = new LinkedList<>();
Class<?> targetClass = clazz;
do {
final LinkedList<InjectionMetadata.InjectedElement> currElements =
new LinkedList<>();
ReflectionUtils.doWithLocalFields(targetClass, field -> {
if (webServiceRefClass != null && field.isAnnotationPresent(webServiceRefClass)) {
if (Modifier.isStatic(field.getModifiers())) {
throw new IllegalStateException("@WebServiceRef annotation is not supported on static fields");
}
currElements.add(new WebServiceRefElement(field, field, null));
}
else if (ejbRefClass != null && field.isAnnotationPresent(ejbRefClass)) {
if (Modifier.isStatic(field.getModifiers())) {
throw new IllegalStateException("@EJB annotation is not supported on static fields");
}
currElements.add(new EjbRefElement(field, field, null));
}
//解析@Resource.class
else if (field.isAnnotationPresent(Resource.class)) {
if (Modifier.isStatic(field.getModifiers())) {
throw new IllegalStateException("@Resource annotation is not supported on static fields");
}
if (!ignoredResourceTypes.contains(field.getType().getName())) {
currElements.add(new ResourceElement(field, field, null));
}
}
});
}上面的代码块出现了期待已久的“Resource.class”关键字，我们就放心了。
我们再回顾一下，
其流程是这样的：在AbstractAutowireCapableBeanFactory.populateBean()->ibp.postProcessPropertyValue()->CommonAnnotationBeanPostProcessor.postProcessPropertyValue()去实例化@Resource作用的bean;
除了和处理@Autowired不是一个PostProcessor（处理@AutoWireds是用这个“AutowiredAnnotationBeanPostProcessor”PostProcessor）其他处理流程和@Autowired的处理流程一毛一样啊！
以上就是Spring Boot如何处理@Resource示例分析的详细内容，更多关于Spring Boot处理@Resource的资料请关注脚本之家其它相关文章！