1. 给Bean设置生命周期方法

1.1. 单实例Bean

@Data
public class Car {
    private String name;
    private Double price;
    public void init() {
        System.out.println("调用init()");
    }
    public void destroy() {
        System.out.println("调用destroy()");
    }
}

1	<bean id="car" class="bean.Car" init-method="init" destroy-method="destroy" />

@Test
public void test() throws Exception {
    ApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    Car car1 = (Car) ioc.getBean("car");
    Car car2 = (Car) ioc.getBean("car");
}

运行测试方法，发现只能看到init()被调用，没有看到destroy()。原因是程序运行完后，spring容器没来得及销毁bean，进程立即就结束了。

调用init()

IOC容器其实有一个close方法，只是ApplicationContext接口没有

@Test
public void test() throws Exception {
    // 将ApplicationContext修改为子接口ConfigurableApplicationContext
    ConfigurableApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    Car car1 = (Car) ioc.getBean("car");
    Car car2 = (Car) ioc.getBean("car");
    // 手动销毁IOC容器
    ioc.close();
}

运行，可以看到init和destroy都被调用了。可以得知，单实例Bean的生命周期为：

容器创建之后，实例化Bean，为Bean设置属性，调用init-method
容器销毁之前，调用Bean的destroy-method

1 2	调用init() 调用destroy()

1.2. 多实例Bean

1 2	<bean id="car" class="bean.Car" scope="prototype" init-method="init" destroy-method="destroy" />

@Test
public void test() throws Exception {
    // 将ApplicationContext修改为子接口ConfigurableApplicationContext
    ConfigurableApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    Car car1 = (Car) ioc.getBean("car");
    Car car2 = (Car) ioc.getBean("car");
    // 手动销毁IOC容器
    ioc.close();
}