共计 2039 个字符,预计需要花费 6 分钟才能阅读完成。
还是先贴出测试类:
@Service
public class TransactionServiceTest {
@Resource
private IQrcodeAdScheduleService qrcodeAdScheduleService;
}
Spring Boot 启动之后的的调用栈信息如下:
图 1
图 2
由图 1,图 2 可知 InjectionMetadata.inject() 执行属性织入逻辑,上面是局部细节
protected void inject(Object target, @Nullable String requestingBeanName, @Nullable PropertyValues pvs)
throws Throwable {if (this.isField) {Field field = (Field) this.member;
ReflectionUtils.makeAccessible(field);
// 通过反射对指标 target 对象也就是咱们之前定义的 TransactionServiceTest 的属性赋值
field.set(target, getResourceToInject(target, requestingBeanName));
}
}
其中,CommonAnnotationBeanPostProcessor.ResourceElement 的 member 属性存储的是 Filed 信息,对于本示例就是:
图 3
对于 @Autowired 来说,就是 AutowiredAnnotationBeanPostProcessor.AutowiredFieldElement.inject():
protected void inject(Object bean, @Nullable String beanName, @Nullable PropertyValues pvs) throws Throwable {Field field = (Field) this.member;
Object value;
if (this.cached) {value = resolvedCachedArgument(beanName, this.cachedFieldValue);
}
else {DependencyDescriptor desc = new DependencyDescriptor(field, this.required);
desc.setContainingClass(bean.getClass());
Set<String> autowiredBeanNames = new LinkedHashSet<>(1);
Assert.state(beanFactory != null, "No BeanFactory available");
TypeConverter typeConverter = beanFactory.getTypeConverter();
try {// 递归调用 createBean() 实例化指标 bean 的属性 bean 实例
value = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter);
}
catch (BeansException ex) {throw new UnsatisfiedDependencyException(null, beanName, new InjectionPoint(field), ex);
}
synchronized (this) {if (!this.cached) {if (value != null || this.required) {
this.cachedFieldValue = desc;
registerDependentBeans(beanName, autowiredBeanNames);
if (autowiredBeanNames.size() == 1) {String autowiredBeanName = autowiredBeanNames.iterator().next();
if (beanFactory.containsBean(autowiredBeanName) &&
beanFactory.isTypeMatch(autowiredBeanName, field.getType())) {
this.cachedFieldValue = new ShortcutDependencyDescriptor(desc, autowiredBeanName, field.getType());
}
}
}
else {this.cachedFieldValue = null;}
this.cached = true;
}
}
}
if (value != null) {
// 通过 field 进行赋值
ReflectionUtils.makeAccessible(field);
field.set(bean, value);
}
}
}
其余的流程一毛一样啊~好了,总结的事件,交给读者敌人吧~(太困了,该劳动了)
正文完
发表至: springboot
2022-06-06