使用方法
java
@Slf4j
@Component
public class MyBean implements InitializingBean {
public MyBean() {
log.info("===================> 构造方法");
}
@Override
public void afterPropertiesSet() throws Exception {
log.info("===================> afterPropertiesSet方法");
}
}
Spring中的Bean注入流程
afterPropertieSet()和init-method
在Spring初始化bean的时候,如果该bean实现了InitializingBean接口,并且同时在配置了init-method,系统则是先调用afterPropertieSet()方法,然后再调用init-method中指定的方法。
通过查看Spring加载bean的源码类AbstractAutowiredCapableBeanFactory可以看出:
java
protected void invokeInitMethods(String beanName, Object bean, @Nullable RootBeanDefinition mbd)
throws Throwable {
// 判断bean是否实现InitializingBean接口
boolean isInitializingBean = (bean instanceof InitializingBean);
if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) {
if (logger.isTraceEnabled()) {
logger.trace("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
}
if (System.getSecurityManager() != null) {
try {
AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () -> {
((InitializingBean) bean).afterPropertiesSet();
return null;
}, getAccessControlContext());
}
catch (PrivilegedActionException pae) {
throw pae.getException();
}
}
else {
// 执行InitializingBean接口实现的方法
((InitializingBean) bean).afterPropertiesSet();
}
}
if (mbd != null && bean.getClass() != NullBean.class) {
String initMethodName = mbd.getInitMethodName();
if (StringUtils.hasLength(initMethodName) &&
!(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) &&
!mbd.isExternallyManagedInitMethod(initMethodName)) {
// 使用反射的方式来调用init-method指定的方法
invokeCustomInitMethod(beanName, bean, mbd);
}
}
}