Spring InitializingBean和init-method

package research.spring.beanfactory.ch4;import org.springframework.beans.factory.InitializingBean;public class LifeCycleBean implements InitializingBean{public void afterPropertiesSet() throws Exception {System.out.println("LifeCycleBean initializing...");}}

xml version="1.0" encoding="UTF-8"?>DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN""http://www.springframework.org/dtd/spring-beans.dtd"><beans><bean name="lifeBean" class="research.spring.beanfactory.ch4.LifeCycleBean">bean>beans>

package research.spring.beanfactory.ch4;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.core.io.ClassPathResource;public class LifeCycleTest {public static void main(String[] args) {XmlBeanFactory factory=new XmlBeanFactory(new ClassPathResource(
"research/spring/beanfactory/ch4/context.xml"));factory.getBean("lifeBean");}}

package research.spring.beanfactory.ch4;public class LifeCycleBean{public void init(){System.out.println("LifeCycleBean.init...");}}

xml version="1.0" encoding="UTF-8"?>DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN""http://www.springframework.org/dtd/spring-beans.dtd"><beans><bean name="lifeBean" class="research.spring.beanfactory.ch4.LifeCycleBean"
 init-method="init">bean>beans>

    <bean name="beanName" class="package.bean"
 init-method="init">
    </bean>

initializingBean接口是spring提供的，子类要实现afterPropertiesSet()方法，init-method是用户可以通过属性文件配置的。从这里可以看出实现initializingBean接口是要和spring耦合的，而init-method则不会。但afterPropertiesSet（）方法spring可以直接调用执行，init-method指定的方法却需要通过反射来执行，从效率来上讲没有afgerPropertiesSet（）快。InitializingBean和init-method可以一起使用，Spring会先处理InitializingBean再处理init-method。
下面是一个小例子，initializingBean接口和init-method都实现了，可以自己随便改。
试验用的bean：
package researchspring.beanfactory;

import org.springframework.beans.factory.InitializingBean;

public class LifeCycleBean implements InitializingBean{
    
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void afterPropertiesSet() throws Exception {
        System.out.println("Implements initializing start.....");
        if(name == null)
            System.out.println("configuration failed!");
        System.out.println("Implements initializing end!");
    }
    
    public void init() {
        System.out.println("init() initializing start.....");
        if(name == null)
            System.out.println("configuration failed!");
        System.out.println("init() initializing end!");
    }
}
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
    
    <bean id="lifeBean" class="researchspring.beanfactory.LifeCycleBean"
        init-method="init" >
    <property name="name" value="apple"></property>
    </bean>
</beans>
测试类：
public class Test {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        LifeCycleBean lifeBean = (LifeCycleBean)ac.getBean("lifeBean");
    }

}

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另外，从网上找了这么一段

//……
//在一个bean的合作者设备完成后，执行一个bean的初始化方法。

protected void invokeInitMethods(String beanName, Object bean, RootBeanDefinition mergedBeanDefinition)
 throws Throwable {
//判断bean是否实现了InitializingBean接口

if (bean instanceof InitializingBean) {
if (logger.isDebugEnabled()) {
logger.debug("Invoking afterPropertiesSet() on bean with name ‘" + beanName + "‘");
}
//调用afterPropertiesSet方法

((InitializingBean) bean).afterPropertiesSet();
}
//判断bean是否定义了init-method

if(mergedBeanDefinition!=null&&mergedBeanDefinition.getInitMethodName() != null) {
//调用invokeCustomInitMethod方法来执行init-method定义的方法

invokeCustomInitMethod(beanName, bean, mergedBeanDefinition.getInitMethodName());
}
}
//执行一个bean定义的init-method方法

protected void invokeCustomInitMethod(String beanName, Object bean, String initMethodName)
throws Throwable {
if (logger.isDebugEnabled()) {
logger.debug("Invoking custom init method ‘" + initMethodName +
"‘ on bean with name ‘" + beanName + "‘");
}
//使用方法名，反射Method对象

Method initMethod = BeanUtils.findMethod(bean.getClass(), initMethodName, null);
if (initMethod == null) {
throw new NoSuchMethodException(
"Couldn‘t find an init method named ‘" + initMethodName + "‘ on bean with name ‘" + beanName + "‘");
}
//判断方法是否是public

if (!Modifier.isPublic(initMethod.getModifiers())) {
//设置accessible为true，可以访问private方法。
                     initMethod.setAccessible(true);
}
try {
//反射执行这个方法

initMethod.invoke(bean, (Object[]) null);
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
//………..