第一种方法，继承InitializingBean和DisposableBean方法
继承前者实现afterPropertiesSet方法，继承后者实现destroy方法，
代码示例：
定义一个实体类：
public class Info {
}
定义另一个实体类实现InitializingBean和DisposableBean接口：
public class Bus implements InitializingBean,DisposableBean {
private Info info;
public void setInfo(Info info) {
System.out.println("setInfo");
this.info = info;
}
public Info getInfo() {
return info;
}
public Bus(){
System.out.println("bus constr");
}
//InitializingBean的方法
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("==============afterPropertiesSet==========");
}
@Override
public void destroy() throws Exception {
System.out.println("=================destroy===================");
}
}
配置类：
@Configuration
public class AppContext {
@Bean
public Info info(){
return new Info();
}
@Bean
public Bus createBus(){
Bus bus = new Bus();
bus.setInfo(info());
return bus;
}
}
测试类：
public class Test {
public static void main(String[] args) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppContext.class);
Bus bus = context.getBean(Bus.class);
System.out.println(bus);
context.close();
}
}
测试结果：
bus constr
setInfo
==============afterPropertiesSet==========
com.zhihao.miao.bean.demo4.Bus@73d4cc9e
=================destroy===================
我们发现继承InitializingBean接口实现的afterPropertiesSet方法在属性设置之后执行，继承DisposableBean接口实现destroy方法在对象销毁之后执行。
InitializingBean接口
Interface to be implemented by beans that need to react once all their properties have been set by a BeanFactory: for example, to perform custom initialization, or merely to check that all mandatory properties have been set.
这个接口的实现在所有属性被BeanFactory设置之后才被执行：比如说。执行自定义的初始化或者检查虽有必要的属性是否被设置。
An alternative to implementing InitializingBean is specifying a custom init-method, for example in an XML bean definition. For a list of all bean lifecycle methods, see the BeanFactory javadocs.
实现InitializingBean的替代方法是指定一个自定义的init方法，例如在一个XML bean定义中。 有关所有bean生命周期的方法，请参阅BeanFactory 帮助文档
DisposableBean接口
Interface to be implemented by beans that want to release resources on destruction. A BeanFactory is supposed to invoke the destroy method if it disposes a cached singleton. An application context is supposed to dispose all of its singletons on close.
这个接口的实现在bean实例被销毁的时候释放资源被调用。BeanFactory支持调用destroy方法处理缓存单列。
An alternative to implementing DisposableBean is specifying a custom destroy-method, for example in an XML bean definition. For a list of all bean lifecycle methods, see the BeanFactory javadocs.
实现DisposableBean的替代方法是指定一个自定义的destroy方法，例如在XML bean定义。 有关所有bean生命周期方法，请参阅BeanFactory 帮组文档。
第二种方式使用@Bean注解的参数
定义一个实例类，并在实例类中定义初始化方法和销毁方法
public class Bike {
public void init(){
System.out.println("=== bike ===init ====");
}
public void destroy() {
System.out.println("===== bike ===destroy ====");
}
}
定义一个AppContext类，用@Configuration注解标记一下
@Configuration
public class AppContext {
@Bean(initMethod="init",destroyMethod="destroy")
public Bike createBike(){
return new Bike();
}
}
测试：
public class Test {
public static void main(String[] args) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppContext.class);
System.out.println(context.getBean(Bike.class));
context.close();
}
}
执行结果：
=== bike ===init ====
com.zhihao.miao.bean.demo5.Bike@68ceda24
===== bike ===destroy ====
第三种使用@PostConstruct和@PreDestroy注解
定义一个实体类：
public class Train {
@PostConstruct
public void initial(){
System.out.println("......initial......");
}
@PreDestroy
public void close(){
System.out.println("......close.........");
}
}
定义一个实体类，配置了@Configuration注解：
@Configuration
public class AppContext {
@Bean
public Train createTrain(){
return new Train();
}
}
测试：
public class Test {
public static void main(String[] args) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppContext.class);
System.out.println(context.getBean(Train.class));
context.close();
}
}
测试结果：
......initial......
com.zhihao.miao.bean.demo6.Train@4516af24
......close.........
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