Spring、Bean的生命周期

1、默认情况下，在Bean容器被实例化的时候，bean对象将被创建：

public class PersonServiceImpl implements PersonIService {

public PersonServiceImpl(){
System.out.println("初始化！！！");
}
@Override
public void helloSpring() {
System.out.println("Hello Spring!");
}
}

<bean id="personIService" class="cn.server.impl.PersonServiceImpl"/>

测试：

@Test
public void test() {
ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
//PersonIService personIService=(PersonIService)ac.getBean("personIService");
}

结果：



2、设置bean的lazy-init属性可以决定Bean是的实例对象是否使用懒加载，默认lazy-init=“false”: 当lazy-init设置为True的时候，只有Bean被实例的时候才调用：

@Test
public void test() {
ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
PersonIService personIService=(PersonIService)ac.getBean("personIService");
}

<bean id="personIService" class="cn.server.impl.PersonServiceImpl" lazy-init="true"/>

3、在bean被实例之前和在bean实例之后都可以执行某些方法，只要设置bean的init-method属性和destroy-method方法即可：

public class PersonServiceImpl implements PersonIService {

public void initBean(){
System.out.println("被实例之前调用");
}
public void destoryBean(){
System.out.println("实例被关闭之后调用");
}
@Override
public void helloSpring() {
System.out.println("Hello Spring!");
}
}

<bean id="personIService" class="cn.server.impl.PersonServiceImpl"
lazy-init="false" init-method="initBean" destroy-method="destoryBean"/>

测试代码：

@Test
public void test() {
AbstractApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
PersonIService personIService=(PersonIService)ac.getBean("personIService");
personIService.helloSpring();
ac.close();
}