spring-bean的生命周期

这里拿两个类进行举例

app.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.xsd">


    <bean id="user" class="com.java12.spring.life.UserLife.User" lazy-init="true">
        <property name="beanName" value="guozhibo"></property>
    </bean>
    <bean id="admin" class="com.java12.spring.life.admin.Admin" init-method="init" destroy-method="aa"></bean>
</beans>

User

public class User implements BeanNameAware{

    private String beanName;
    private String name;

    public void setName(String name) {
        System.out.println("给属性赋值");
        this.name = name;
    }

    public User() {
        System.out.println("对象被实例化");
    }

    public User(String beanName) {
        this.beanName = beanName;
    }

    public String getBeanName() {
        return beanName;
    }

    @Override
    public void setBeanName(String s) {
        this.beanName = s;
    }

    @Override
    public String toString() {
        return "User{" +
                "beanName='" + beanName + '\'' +
                '}';
    }
}public class User implements BeanNameAware{

    private String beanName;
    private String name;

    public void setName(String name) {
        System.out.println("给属性赋值");
        this.name = name;
    }

    public User() {
        System.out.println("对象被实例化");
    }

    public User(String beanName) {
        this.beanName = beanName;
    }

    public String getBeanName() {
        return beanName;
    }

    @Override
    public void setBeanName(String s) {
        this.beanName = s;
    }

    @Override
    public String toString() {
        return "User{" +
                "beanName='" + beanName + '\'' +
                '}';
    }
}

BeanNameAware实现这个接口，可以用于测试执行过程

spring在执行过程中，首先会实例化这个类，然后去给属性赋值，紧接着调用BeanNameAware下的setBeanName这个方法

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Admin

public class Admin implements BeanFactoryAware{

    private BeanFactory beanFactory;



    private ApplicationContext applicationContext;
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
            this.beanFactory = beanFactory;
        System.out.println("这是第二步通过BeanFactoryAware获取容器");

    }
}

实现BeanFactoryAware这个接口，就回调用setBeanFactory这个方法，这里可以拿到spring容器中的实例，可以对之就行加工

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

public class Admin implements BeanFactoryAware,ApplicationContextAware{

    private BeanFactory beanFactory;



    private ApplicationContext applicationContext;
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
            this.beanFactory = beanFactory;
        System.out.println("这是第二步通过BeanFactoryAware获取容器");

    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
        int beanDefinitionCount = applicationContext.getBeanDefinitionCount();
        String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames();
        for (String str:beanDefinitionNames) {
            System.out.println(str);
        }
        System.out.println("第三步获取所有id："+beanDefinitionCount);
    }

实现了ApplicationContextAware这个接口，就会调用setApplicationContext这个方法，这里可以获取到容器中所有的bean，我们可以对其进行修饰

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

public class Admin1 implements InitializingBean，BeanPostProcessor{
    
    @Override
    public Object postProcessBeforeInitialization(Object o, String s) throws BeansException {
        System.out.println("预------------------------"+o);
        return o;
    }

@Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("aaaaaaaaaaaaaaaaaaaa");
    }

    @Override
    public Object postProcessAfterInitialization(Object o, String s) throws BeansException {
        System.out.println("初始化");
        return o;
    }   }    

    
}

实现InitializingBean接口，就回调用他自己的初始化方法，对于整个容器而言，谁实现了这个接口，就在实现的那个地方进行初始化这一步在预初始化之前的后面执行执行顺序如图所示

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------如果bean实现了InitializingBean接口，Spring将调用它们的afterPropertiesSet()方法。类似地，如果bean使用init-method声明了初始化方法，该方法也会被调用。如果既采用init-method属性指定初始化方法，又实现InitializingBean接口来指定初始化方法的话，Spring会先执行InitializingBean接口中定义的方法，然后执行init-method属性指定的方法。

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

bean完成一系列初始化工作可以被使用了

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

最后

public class Admin implements DisposableBean{
 @Override
    public void destroy() throws Exception {
        System.out.println("默认销毁");
    }

    private void aa() {
        System.out.println("手动销毁");
    }
}

如果bean实现了DisposableBean这个接口，spring将调用destroy方法，如果bean实现了DisposableBean接口，Spring将调用它的destroy()接口方法，同样，如果bean使用了destroy-method声明了销毁方法，该方法也会被调用。

spring-bean的生命周期

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