BeanPostProcessor接口的行为方法

public interface BeanPostProcessor {    /**     * Apply this BeanPostProcessor to the given new bean instance before any bean     * initialization callbacks (like InitializingBean's {
    @code afterPropertiesSet}     * or a custom init-method). The bean will already be populated with property values.     * The returned bean instance may be a wrapper around the original.     * @param bean the new bean instance     * @param beanName the name of the bean     * @return the bean instance to use, either the original or a wrapped one; if     * {
    @code null}, no subsequent BeanPostProcessors will be invoked     * @throws org.springframework.beans.BeansException in case of errors     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet     */    Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;    /**     * Apply this BeanPostProcessor to the given new bean instance after any bean     * initialization callbacks (like InitializingBean's {
    @code afterPropertiesSet}     * or a custom init-method). The bean will already be populated with property values.     * The returned bean instance may be a wrapper around the original.     * 
In case of a FactoryBean, this callback will be invoked for both the FactoryBean     * instance and the objects created by the FactoryBean (as of Spring 2.0). The     * post-processor can decide whether to apply to either the FactoryBean or created     * objects or both through corresponding {
    @code bean instanceof FactoryBean} checks.     * 
This callback will also be invoked after a short-circuiting triggered by a     * {
    @link InstantiationAwareBeanPostProcessor#postProcessBeforeInstantiation} method,     * in contrast to all other BeanPostProcessor callbacks.     * @param bean the new bean instance     * @param beanName the name of the bean     * @return the bean instance to use, either the original or a wrapped one; if     * {
    @code null}, no subsequent BeanPostProcessors will be invoked     * @throws org.springframework.beans.BeansException in case of errors     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet     * @see org.springframework.beans.factory.FactoryBean     */    Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;}

自定义的BeanPostProcessor

package com.wjz.spring;import org.springframework.beans.BeansException;import org.springframework.beans.factory.config.BeanPostProcessor;import com.wjz.core.CustomInitializable;public class CustomBeanPostProcessor implements BeanPostProcessor {    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {        if (bean instanceof CustomInitializable) {            System.out.println("before init......");            ((CustomInitializable) bean).init();        }        return bean;    }    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {        System.out.println("after init......");        return bean;    }}

自定义的修改

package com.wjz.core;public abstract interface CustomInitializable {    abstract void init();}

package com.wjz.core;public class Realm implements CustomInitializable {    public void init() {        System.out.println("init......");    }}

关于Shiro框架对于BeanPostProcessor的使用

LifecycleBeanPostProcessor

 

public Object postProcessBeforeInitialization(Object object, String name) throws BeansException {        if (object instanceof Initializable) {            try {                if (log.isDebugEnabled()) {                    log.debug("Initializing bean [" + name + "]...");                }                ((Initializable) object).init();            } catch (Exception e) {                throw new FatalBeanException("Error initializing bean [" + name + "]", e);            }        }        return object;    }    /**     * Does nothing - merely returns the object argument immediately.     */    public Object postProcessAfterInitialization(Object object, String name) throws BeansException {        // Does nothing after initialization        return object;    }

public abstract interface org.apache.shiro.util.Initializable {      public abstract void init() throws org.apache.shiro.ShiroException;}

AuthenticatingRealm

public final void init() {        //trigger obtaining the authorization cache if possible 如果可能，触发获得授权缓存        getAvailableAuthenticationCache();        onInit();    }