springboot 对象生命周期

深碍√TFBOYSˉ_ 2023-02-24 14:27 22阅读 0赞

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### springboot 对象生命周期 ###

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**spring bean的生命周期**

**spring bean从创建到销毁大致过程：实例化、属性注入、初始化、使用、销毁，具体过程：**

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**实例化：**调用构造函数为对象分配内存空间

**属性注入：**为对象注入属性

**setBeanName：**如果对象实现了**BeanNameAware**接口，则调用该方法

**setBeanFactory：**如果对象实现了**BeanFactoryAware**接口，则调用该方法

**setApplicationContext：**如果实现了**ApplicationContextAware**接口，且spring ioc容器也是ApplicationContext的接口实现类，则调用该方法

**postProcessBeforeInitialization：**如果实现了**BeanPostProcess**接口，则调用该方法

**afterPropertiesSet：**如果实现了**InitializingBean**接口，则调用该方法

**init-method：**如果设置了自定义初始化方法，则调用自定义初始化方法

**postProcessAfterInitialization：**如果实现了**BeanPostProcess**接口，则调用该方法

**初始化完成，此时可以使用对象**

**使用完成后，销毁对象**

**destory：**如果实现了**DisposableBean**接口，则调用该方法

**destroyMethod：**如果自定义了销毁方法，则调用该方法

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**相关接口**

**BeanNameAware**

public interface BeanNameAware extends Aware {
    
    	void setBeanName(String name);
    
    }

**Aware**

public interface Aware {
    
    }

**BeanFactoryAware**

public interface BeanFactoryAware extends Aware {
    
    	void setBeanFactory(BeanFactory beanFactory) throws BeansException;
    
    }

**ApplicationContextAware**

public interface ApplicationContextAware extends Aware {
        void setApplicationContext(ApplicationContext var1) throws BeansException;
    }

**BeanPostProcessor：针对所有bean都生效**

public interface BeanPostProcessor {
    
    	@Nullable
    	default Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
    		return bean;
    	}
    
    	@Nullable
    	default Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    		return bean;
    	}
    
    }

**InitializingBean**

public interface InitializingBean {
    
    	void afterPropertiesSet() throws Exception;
    
    }

**DisposableBean**

public interface DisposableBean {
    
    	void destroy() throws Exception;
    
    }

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**示例**

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**pojo 层**

**Person**

@Component
    public class Person {
    
        private String name;
        private Integer age;
    
        public Person(){
            System.out.println("person 开始实例化");
    
            this.name="瓜田李下";
            this.age=20;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (!(o instanceof Person)) return false;
            Person person = (Person) o;
            return Objects.equals(getName(), person.getName()) &&
                    Objects.equals(getAge(), person.getAge());
        }
    
        @Override
        public int hashCode() {
            return Objects.hash(getName(), getAge());
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

**Student**

@Data
    public class Student implements BeanNameAware, BeanFactoryAware, ApplicationContextAware, InitializingBean, DisposableBean {
    
        private String name;
        private Integer age;
    
        public Student(){
            System.out.println("student 开始实例化");
    
            this.name="瓜田李下";
            this.age=20;
        }
    
        @Override
        public void setBeanName(String name) {
            System.out.println("student设置对象名称："+name);
        }
    
        @Override
        public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
            System.out.println("student 设置容器工厂："+beanFactory);
        }
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            System.out.println("student 设置应用上下文："+applicationContext);
        }
    
        @Override
        public void afterPropertiesSet() throws Exception {
            System.out.println("student 调用afterProperties");
        }
    
        @Override
        public void destroy() throws Exception {
            System.out.println("student 调用 DisposableBean destroy 方法");
        }
    
        public void initMethod(){
            System.out.println("student 调用自定义初始化方法");
        }
    
        public void destroyMethod(){
            System.out.println("student 调用自定义销毁方法");
        }
    }

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**config 层**

**WebConfig**

@Configuration
    public class WebConfig {
    
        @Bean(name = "student",initMethod = "initMethod",destroyMethod = "destroyMethod")
        public Student initStudent(){
            return new Student();
        }
    }

**CustomBeanPostProcessor**

@Component
    public class CustomBeanPostProcessor implements BeanPostProcessor {
    
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person||bean instanceof Student){
                System.out.println("调用"+bean.getClass().getSimpleName()+"前置方法");
            }
    
            return bean;
        }
    
        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person||bean instanceof Student){
                System.out.println("调用"+bean.getClass().getSimpleName()+"后置方法");
            }
    
            return bean;
        }
    }

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**controller 层**

**HelloController**

@RestController
    public class HelloController {
    
        @Resource
        private Person person;
    
        @Resource
        private Student student;
    
        @Resource
        private ConfigurableApplicationContext applicationContext;
    
        @RequestMapping("/hello")
        public void hello(){
            System.out.println(person);
            System.out.println(student);
    
            applicationContext.close();
        }
    }

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**使用测试**

**localhost:8080/hello**

person 开始实例化
    调用Person前置方法
    调用Person后置方法
    student 开始实例化
    student设置对象名称：student
    student 设置容器工厂：org.springframework.beans.factory.support.DefaultListableBeanFactory@41294f8: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.event.internalEventListenerProcessor,org.springframework.context.event.internalEventListenerFactory,demoApplication,org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory,customBeanPostProcessor,webConfig,helloController,person,student,org.springframework.boot.autoconfigure.AutoConfigurationPackages,org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,propertySourcesPlaceholderConfigurer,org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration$TomcatWebSocketConfiguration,websocketServletWebServerCustomizer,org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryConfiguration$EmbeddedTomcat,tomcatServletWebServerFactory,org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,servletWebServerFactoryCustomizer,tomcatServletWebServerFactoryCustomizer,org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor,org.springframework.boot.context.internalConfigurationPropertiesBinderFactory,org.springframework.boot.context.internalConfigurationPropertiesBinder,org.springframework.boot.context.properties.BoundConfigurationProperties,org.springframework.boot.context.properties.ConfigurationPropertiesBeanDefinitionValidator,org.springframework.boot.context.properties.ConfigurationBeanFactoryMetadata,server-org.springframework.boot.autoconfigure.web.ServerProperties,webServerFactoryCustomizerBeanPostProcessor,errorPageRegistrarBeanPostProcessor,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletConfiguration,dispatcherServlet,spring.mvc-org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration,dispatcherServletRegistration,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,taskExecutorBuilder,applicationTaskExecutor,spring.task.execution-org.springframework.boot.autoconfigure.task.TaskExecutionProperties,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration,error,beanNameViewResolver,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration$DefaultErrorViewResolverConfiguration,conventionErrorViewResolver,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,errorAttributes,basicErrorController,errorPageCustomizer,preserveErrorControllerTargetClassPostProcessor,spring.resources-org.springframework.boot.autoconfigure.web.ResourceProperties,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration,requestMappingHandlerAdapter,requestMappingHandlerMapping,welcomePageHandlerMapping,mvcConversionService,mvcValidator,mvcContentNegotiationManager,mvcPathMatcher,mvcUrlPathHelper,viewControllerHandlerMapping,beanNameHandlerMapping,routerFunctionMapping,resourceHandlerMapping,mvcResourceUrlProvider,defaultServletHandlerMapping,handlerFunctionAdapter,mvcUriComponentsContributor,httpRequestHandlerAdapter,simpleControllerHandlerAdapter,handlerExceptionResolver,mvcViewResolver,mvcHandlerMappingIntrospector,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter,defaultViewResolver,viewResolver,requestContextFilter,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,formContentFilter,org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,mbeanExporter,objectNamingStrategy,mbeanServer,org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,springApplicationAdminRegistrar,org.springframework.boot.autoconfigure.aop.AopAutoConfiguration$ClassProxyingConfiguration,org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration,applicationAvailability,org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration,lifecycleProcessor,spring.lifecycle-org.springframework.boot.autoconfigure.context.LifecycleProperties,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$Jackson2ObjectMapperBuilderCustomizerConfiguration,standardJacksonObjectMapperBuilderCustomizer,spring.jackson-org.springframework.boot.autoconfigure.jackson.JacksonProperties,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperBuilderConfiguration,jacksonObjectMapperBuilder,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$ParameterNamesModuleConfiguration,parameterNamesModule,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration,jacksonObjectMapper,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,jsonComponentModule,org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration,stringHttpMessageConverter,org.springframework.boot.autoconfigure.http.JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration,mappingJackson2HttpMessageConverter,org.springframework.boot.autoconfigure.http.JacksonHttpMessageConvertersConfiguration,org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,messageConverters,org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,spring.info-org.springframework.boot.autoconfigure.info.ProjectInfoProperties,org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,spring.security.oauth2.resourceserver-org.springframework.boot.autoconfigure.security.oauth2.resource.OAuth2ResourceServerProperties,org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,taskSchedulerBuilder,spring.task.scheduling-org.springframework.boot.autoconfigure.task.TaskSchedulingProperties,org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,restTemplateBuilder,org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration$TomcatWebServerFactoryCustomizerConfiguration,tomcatWebServerFactoryCustomizer,org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,characterEncodingFilter,localeCharsetMappingsCustomizer,org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,multipartConfigElement,multipartResolver,spring.servlet.multipart-org.springframework.boot.autoconfigure.web.servlet.MultipartProperties]; root of factory hierarchy
    student 设置应用上下文：org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@7f485fda, started on Thu Jul 09 19:40:30 GMT+08:00 2020
    调用Student前置方法
    student 调用afterProperties
    student 调用自定义初始化方法
    调用Student后置方法
    2020-07-09 19:40:31.134  INFO 14704 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
    2020-07-09 19:40:31.297  INFO 14704 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
    2020-07-09 19:40:31.305  INFO 14704 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 1.63 seconds (JVM running for 2.314)
    2020-07-09 19:40:35.100  INFO 14704 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
    2020-07-09 19:40:35.101  INFO 14704 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
    2020-07-09 19:40:35.110  INFO 14704 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 9 ms
    Person{name='瓜田李下', age=20}
    Student(name=瓜田李下, age=20)
    2020-07-09 19:40:37.295  INFO 14704 --- [nio-8080-exec-1] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
    student 调用 DisposableBean destroy 方法
    student 调用自定义销毁方法

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