spring(二)：bean的生命周期
bean的生命周期指的是bean的创建——>初始化——>销毁的过程，该过程是由spring容器进行管理的
我们可以自定义bean初始化和销毁的方法：容器在bean进行到当前生命周期时，调用自定义的初始化和销毁方法
自定义初始化和销毁方法
init-method、destroy-method
配置文件的bean标签中配置init-method、destroy-method属性
<bean id="user" class="com.enjoy.study.pojo.User" init-method="init" destroy-method="destroy"/>
bean类
public class User {
public User() {
System.out.println("user....constructor..........");
}
public void init(){
System.out.println("user....init..........");
}
public void destroy(){
System.out.println("user....destroy..........");
}
}
测试类
public class Cap7Test {
@Test
public void cap7Test(){
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:beans.xml");
System.out.println("ioc容器启动完成");
context.close();
}
}
结果
user....constructor..........
user....init..........
ioc容器启动完成
user....destroy..........
initMethod、destroyMethod
@Bean配置initMethod、destroyMethod属性
单实例情况：
@Configuration
public class Cap7MainConfig {
@Bean(initMethod = "init",destroyMethod = "destroy")
public User user(){
return new User();
}
}
测试方法
@Test
public void annoTest(){
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(Cap7MainConfig.class);
System.out.println("ioc容器启动完成");
context.close();
}
结果
user....constructor..........
user....init..........
ioc容器启动完成
user....destroy..........
多实例情况：
@Configuration
public class Cap7MainConfig {
@Scope("prototype")
@Bean(initMethod = "init",destroyMethod = "destroy")
public User user(){
return new User();
}
}
结果
ioc容器启动完成
单实例情况下，容器启动时完成bean的实例化，容器关闭时进行bean的销毁
多实例情况下，容器启动时不进行bean的实例化，获取bean时实例化bean对象，所以启动后直接关闭容器，容器中并未进行bean的管理
InitializingBean、DisposableBean接口
bean实现InitializingBean接口，实现afterPropertiesSet()方法：beanFactory创建对象完成，并且设置完属性后，调用该方法，相当于初始化方法
bean实现DisposableBean接口，实现destroy()方法：bean对象销毁时，调用该方法
public class User implements InitializingBean,DisposableBean {
public User() {
System.out.println("user....constructor..........");
}
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("user....afterPropertiesSet.........");
}
@Override
public void destroy() throws Exception {
System.out.println("user....destroy............");
}
}
配置类
@Configuration
public class Cap7MainConfig {
@Bean
public User user(){
return new User();
}
}
结果
user....constructor..........
user....afterPropertiesSet.........
ioc容器启动完成
user....destroy............
@PostConstruct、@PreDestroy
@Component
public class User{
public User() {
System.out.println("user....constructor..........");
}
//对象创建并赋值后使用
@PostConstruct
public void init() {
System.out.println("user....init.........");
}
//容器移除对象之前回调通知，销毁bean
@PreDestroy
public void destroy() {
System.out.println("user....destroy............");
}
}
配置类
@Configuration
@ComponentScan("com.enjoy.study.cap7")
public class Cap7MainConfig {
}
结果
user....constructor..........
user....init.........
ioc容器启动完成
user....destroy............
BeanPostProcessor
后置处理器，负责在初始化前后做相应处理
/**
* 后置处理器
* @Component，将后置处理器加入容器中
* @author qf
* @create 2019-05-22 10:05
*/
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
/**
* 在初始化之前进行相应后置处理工作。比如在init-method方法执行之前，或者initializingBean的afterPropertiesSet方法之前
* @param bean
* @param beanName
* @return
* @throws BeansException
*/
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println("postProcessBeforeInitialization......"+bean+"........."+beanName);
return bean;
}
/**
* 在初始化之后进行相应后置处理工作
* @param bean
* @param beanName
* @return
* @throws BeansException
*/
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
System.out.println("postProcessAfterInitialization......"+bean+"........."+beanName);
return bean;
}
}
测试
@Component
public class User implements InitializingBean,DisposableBean {
@Override
public void destroy() throws Exception {
System.out.println("user....destroy........");
}
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("user....afterPropertiesSet........");
}
}
配置类
@Configuration
@ComponentScan("com.enjoy.study.cap8")
public class Cap8MainConfig {
}
测试类
public class Cap8Test {
@Test
public void cap8Test(){
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(Cap8MainConfig.class);
System.out.println("ioc容器创建完成");
context.close();
}
}
结果
postProcessBeforeInitialization...............org.springframework.context.event.internalEventListenerProcessor
postProcessAfterInitialization...............org.springframework.context.event.internalEventListenerProcessor
postProcessBeforeInitialization...............org.springframework.context.event.internalEventListenerFactory
postProcessAfterInitialization...............org.springframework.context.event.internalEventListenerFactory
postProcessBeforeInitialization...............cap8MainConfig
postProcessAfterInitialization...............cap8MainConfig
postProcessBeforeInitialization...............user
user....afterPropertiesSet........
postProcessAfterInitialization...............user
ioc容器创建完成
user....destroy........
