spring启动加载程序的几种方法介绍

import javax.annotation.PostConstruct; 
import javax.annotation.PreDestroy; 
 
public class DataInitializer{  
 @PostConstruct 
 public void initMethod() throws Exception { 
  System.out.println("initMethod 被执行"); 
 } 
 @PreDestroy 
 public void destroyMethod() throws Exception { 
  System.out.println("destroyMethod 被执行"); 
 } 
} 

public class DataInitializer{ 
 public void initMethod() throws Exception { 
  System.out.println("initMethod 被执行"); 
 } 
 public void destroyMethod() throws Exception { 
  System.out.println("destroyMethod 被执行"); 
 } 
} 

import org.springframework.beans.factory.DisposableBean; 
 
public class DataInitializer implements InitializingBean，DisposableBean{ 
  
 @Override 
 public void afterPropertiesSet() throws Exception { 
  System.out.println("afterPropertiesSet 被执行"); 
 } 
  
 @Override 
 public void destroy() throws Exception { 
  System.out.println("destroy 被执行"); 
 } 
 
} 

protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd) 
  throws Throwable { 
 //判断该bean是否实现了实现了InitializingBean接口，如果实现了InitializingBean接口，则只掉调用bean的afterPropertiesSet方法 
 boolean isInitializingBean = (bean instanceof InitializingBean); 
 if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) { 
  if (logger.isDebugEnabled()) { 
   logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'"); 
  } 
  
  if (System.getSecurityManager() != null) { 
   try { 
    AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() { 
     public Object run() throws Exception { 
      //直接调用afterPropertiesSet 
      ((InitializingBean) bean).afterPropertiesSet(); 
      return null; 
     } 
    },getAccessControlContext()); 
   } catch (PrivilegedActionException pae) { 
    throw pae.getException(); 
   } 
  }     
  else { 
   //直接调用afterPropertiesSet 
   ((InitializingBean) bean).afterPropertiesSet(); 
  } 
 } 
 if (mbd != null) { 
  String initMethodName = mbd.getInitMethodName(); 
  //判断是否指定了init-method方法，如果指定了init-method方法，则再调用制定的init-method 
  if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && 
    !mbd.isExternallyManagedInitMethod(initMethodName)) { 
    //进一步查看该方法的源码，可以发现init-method方法中指定的方法是通过反射实现 
   invokeCustomInitMethod(beanName, bean, mbd); 
  } 
 }