Bean Spring container life cycle

Bean Spring container life cycle

1. init-method and the method destory-method

When Spring bean initialization bean or destroyed, sometimes need to do some processing work, so spring can call the bean's two life-cycle approach in the creation and removal of the bean.

Such as:

bean id="xxx" class="xxx" init-method="init" destory-method="destory" />

• When bean is loaded into the container when the call init, when removed from the container bean call destory (scope = singleton effective). Init method name and destory can name their own

• web container will automatically call, but the main function or test cases need to manually call

Specific code: SpringDemo3.demo2 ()

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2. Spring Bean container life cycle (understand)

1. instantiate bean object instantiation
2. Package populate properties Properties
3. If the Bean implementation BeanNameAware execution setBeanName
4. If the Bean or ApplicationContextAware achieve BeanFacotryAware factory setting or context object setApplicationContext setBeanFactory
5. If there class implements the BeanPostProcessor (post-treatment Bean), performed postProcessBeforeInitialization
6. If the Bean implementation InitializingBean execution afterPropertiesSet
7. Call the <bean init-method="init">designated initializer init, if the class exists to achieve BeanPostProcessor (processing Bean), the implementation of postProcessAfterInitialization
8. Business process execution
9. If the Bean implementation DisposableBean, execution destroy
10. Call the bean destroy-method="customerDestroy">specified methods of destruction customerDestroy

Among the most important are: Steps 5 and seventh.

Ide accomplish the above process, the printing is as follows:

Specific code: SpringDemo3.demo3 ()

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3. beanpostprocessor role

beanpostprocessor class can be generated in the process of classes, the class generating agent, and can be enhanced class method.

The code below is a beanpostprocessor class, we enhanced the postProcessAfterInitialization initialization method. Enhanced save method in the bean.

public class MyBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        // System.out.println("第五步：初始化前的方法...");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(final Object bean, String beanName) throws BeansException {
        // System.out.println("第八步：初始化后方法...");

        //使用代理，构造匿名函数
        if ("userDao".equals(beanName)) {
            Object proxy = Proxy.newProxyInstance(bean.getClass().getClassLoader(), bean.getClass().getInterfaces(), new InvocationHandler() {
                @Override
                public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                    if ("save".equals(method.getName())) {
                        System.out.println("权限校验==========");
                        // 传入属性
                        return method.invoke(bean, args);
                    }
                    return method.invoke(bean, args);
                }
            });

            return proxy;
        } else {
            return bean;
        }
    }
}

Output is as follows:

Specific code: SpringDemo3.demo4 ()