《读spring源码》17 Bean的生命周期简单探索（基于JSR250规范@PostConStruct@PreDestory）

淡淡的烟草味﹌ 2023-06-18 07:55 1阅读 0赞

可以使用JSR250规范定义的（JAVA规范）两个注解来实现  
@PostConStruct：在bean创建完成，且属于赋值完成后进行初始化，属于JDK规范的注解  
@PreDestory:在bean将被移除之前进行通知，在容器销毁之前进行清理工作

提示：JSR是由JDK提供的一组规范

package com.enjoy.cap7;
    
    import org.springframework.stereotype.Component;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.PreDestroy;
    
    
    @Component
    public class Jeep
    { 
        public Jeep(){ 
            System.out.println("Jeep 构造器");
        }
        @PostConstruct
        public  void init(){ 
            System.out.println("Jeep @PostConstruct");
        }
        @PreDestroy
        public void  destory(){ 
            System.out.println("Jeep @PreDestroy");
        }
    }

package com.enjoy.cap7;
    
    
    import com.enjoy.cap1.Person;
    import com.enjoy.cap6.*;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.Import;
    
    @ComponentScan(value = "com.enjoy.cap7")
    @Configuration
    @Import(value = { Dog.class,Cat.class,TTTTImportSelector.class,TTTImportBeanDefinitionRegistrar.class})
    public class MainConfig { 
    
        @Bean("person")
        public Person zhangsan(){ 
    // System.out.println("给我们的容器中添加张三");
            return new Person("张三",22);
        }
    // @Bean(initMethod = "init",destroyMethod = "destory")
    // public Bike bike(){ 
    // return new Bike();
    // }
    
    
    }

package test;
    
    import com.enjoy.cap7.MainConfig;
    import org.junit.jupiter.api.Test;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    /** * FactoryBean 和 BeanFactorty 有什么区别？ * * FactoryBean ：可以把我们的JAVA实例通过FactoryBean注入到容器中 * * BeanFactorty：从我们的容器中获取实例化后的bean * */
    public class MainTEwst7 { 
    
        @Test
        public void sss(){ 
            AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
            System.out.println("容器起用完成");
    
            annotationConfigApplicationContext.close();
    
        }
    }

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