通达信接口自动下单-BeanPostProcessor接口

作用

BeanPostProcessor接口里面有下面两个方法：实现这两个方法可以在bean的初始化前后进行操作。

实现该接口的类必须注入到容器中才能生效

/**
Apply this BeanPostProcessor to the given new bean instance before any bean initialization callbacks (like InitializingBean's  afterPropertiesSet or a custom init-method). The bean will already be populated with property values. The returned bean instance may be a wrapper around the original.
*/
@Nullable
default Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
    return bean;
}

/**
Apply this BeanPostProcessor to the given new bean instance after any bean initialization callbacks (like InitializingBean's afterPropertiesSet or a custom init-method). The bean will already be populated with property values. The returned bean instance may be a wrapper around the original.
*/
@Nullable
default Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    return bean;
}

使用方法

先实现BeanPostProcessor接口，然后将其注入到容器中

/**
 * 初始化前后进行操作
 * 需要注入到容器中
 * @author Floweryu
 * @date 2022/3/6 20:53
 */
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println('postProcessBeforeInitialization... ' + bean + ' -> [' + beanName + ']');
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println('postProcessAfterInitialization... ' + bean + ' -> [' + beanName + ']');
        return bean;
    }
}

下面，针对不同的初始化的方法，都会在bean的初始化前后生效：

BeanPostProcessor接口

对于实现InitializingBean接口的类

@Component
public class Cat implements InitializingBean, DisposableBean {
    
    public Cat() {
        System.out.println('Cat construct....');
    }
    
    @Override
    public void destroy() throws Exception {
        System.out.println('Cat destroy....');
    }

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

输出：postProcessBeforeInitialization…cofloweryu.examplbeaCat@44a7bfbc->[cat]CatafterPropertiesSet…postProcessAfterInitialization…cofloweryu.examplbeaCat@44a7bfbc->[cat]

对于使用@PostConstruct初始化的类：

@Component
public class Dog {
    public Dog() {
        System.out.println('Dog Construct....');
    }

    /**
     * 对象创建并赋值后使用
     */
    @PostConstruct
    public void init() {
        System.out.println('Dog @PostConstruct....');
    }

    /**
     * 容器移除对象之前使用
     */
    @PreDestroy
    public void destroy() {
        System.out.println('Dog @PreDestroy');
    }
}

输出：postProcessBeforeInitialization…cofloweryu.examplbeaDog@306cf3ea->[dog]Dog@PostConstruct…postProcessAfterInitialization…cofloweryu.examplbeaDog@306cf3ea->[dog]

对于使用@Bean自定义的类

@ComponentScan('com.floweryu.example.bean')
@Configuration
public class MainConfigOfLifeCycle {
    
    @Bean(initMethod = 'init', destroyMethod = 'destory')
    public Car car() {
        return new Car();
    }
}

public class Car {
    
    public Car() {
        System.out.println('construct car...');
    }
    
    public void init() {
        System.out.println('Car init....');
    }
    
    public void destory() {
        System.out.println('Car destory....');
    }
}

通达信接口自动下单怎么操作？