文章目錄

• • • • 序言
      • 一：Bean生命周期流程圖
      • 二：測試方法以及步驟
      • • 1、創建一個bean
        • 2、創建BeanFactoryPostProcessor 的實現實例
        • 3、創建InstantiationAwareBeanPostProcessorAdapter實現實例
        • 4、創建BeanPostProcessor實現實例
        • 5、將實例注冊到Spring中
        • 6、測試代碼
        • 7、運行日志

序言

Bean是Spring框架的核心，無論我們用的是SpringMVC、SpringBoot、SpringCloud都繞不開Bean的構造，理解了Bean的生命周期有利于我們更好的了解自己的項目并且可以對現有的框架做一些擴展。

一：Bean生命周期流程圖

首先，看一下Bean整個生命周期的流程圖，這張圖有利于我們了解整個過程中的調用情況。
原圖：https://www.processon.com/view/link/5e421d84e4b00de9fd84a623

二：測試方法以及步驟

Spring中有很多繼承于Aware中的接口，aware的意思是已知的，所以從這些Aware中我們能從Spring容器獲取到已知的一些信息。
簡單舉例來說，比如我們實現了ApplicationContextAware，我們就可以從里面獲取到ApplicationContext上下文對象。

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

下面通過簡單的代碼示例來模擬bean的生命周期。

1、創建一個bean

這個Bean實現了一下接口：

BeanFactoryAware BeanNameAware BeanClassLoaderAware ResourceLoaderAware MessageSourceAware EnvironmentAware ApplicationContextAware InitializingBean DisposableBean

Bean的實現如下：

public class UserInfo implements BeanFactoryAware,BeanNameAware,BeanClassLoaderAware,ResourceLoaderAware,MessageSourceAware,EnvironmentAware,ApplicationContextAware,InitializingBean,DisposableBean {//用戶idInteger id;//用戶名稱String name;//用戶性別String gender;//用戶年齡String age;//備注String remarks;public UserInfo() {System.out.println(DateUtil.getTimeNow() + "調用UserInfo構造方法");}public void myInit() {System.out.println(DateUtil.getTimeNow() + "調用UserInfo的myInit()方法");}public void myDestroy() {System.out.println(DateUtil.getTimeNow() + "調用UserInfo的myDestroy()方法");}public Integer getId() {return id;}public void setId(Integer id) {System.out.println(DateUtil.getTimeNow() + "調用UserInfo賦值屬性的setId()");this.id = id;}public String getName() {return name;}public void setName(String name) {System.out.println(DateUtil.getTimeNow() + "調用UserInfo賦值屬性的setName()");this.name = name;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}public String getAge() {return age;}public void setAge(String age) {System.out.println(DateUtil.getTimeNow() + "調用UserInfo賦值屬性的setAge()");this.age = age;}public String getRemarks() {return remarks;}public void setRemarks(String remarks) {this.remarks = remarks;}@Overridepublic String toString() {System.out.println(DateUtil.getTimeNow() + "調用UserInfo賦值屬性的toString()");return DateUtil.getTimeNow() + "UserInfo{" +"id=" + id +", name='" + name + '\'' +", gender='" + gender + '\'' +", age='" + age + '\'' +", remarks='" + remarks + '\'' +'}';}@Overridepublic void setBeanClassLoader(ClassLoader classLoader) {System.out.println(DateUtil.getTimeNow() + "調用BeanClassLoaderAware的setBeanClassLoader()");}@Overridepublic void setBeanName(String s) {System.out.println(DateUtil.getTimeNow() + "調用BeanNameAware的setBeanName()");}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用ApplicationContextAware的setApplicationContext()");//模擬獲取系統運行參數String sysProp = applicationContext.getEnvironment().getProperty("System.id");System.out.println(DateUtil.getTimeNow() + "獲取系統參數System.id=" + sysProp);}@Overridepublic void setBeanFactory(BeanFactory beanFactory) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用BeanFactoryAware的setBeanFactory()");}@Overridepublic void setEnvironment(Environment environment) {System.out.println(DateUtil.getTimeNow() + "調用EnvironmentAware的setEnvironment()");System.out.println(DateUtil.getTimeNow() + environment.getProperty("user.dir"));//設置系統運行參數String sysProp = "springtest";System.out.println(DateUtil.getTimeNow() + "設置系統參數System.id=" + sysProp);System.setProperty("System.id", sysProp);}@Overridepublic void afterPropertiesSet() throws Exception {System.out.println(DateUtil.getTimeNow() + "調用InitializingBean的afterPropertiesSet()");}@Overridepublic void setMessageSource(MessageSource messageSource) {System.out.println(DateUtil.getTimeNow() + "調用MessageSourceAware的setMessageSource()");}@Overridepublic void setResourceLoader(ResourceLoader resourceLoader) {System.out.println(DateUtil.getTimeNow() + "調用BeanClassLoaderAware的setBeanClassLoader()");}@Overridepublic void destroy() throws Exception {System.out.println(DateUtil.getTimeNow() + "調用DisposableBean賦值屬性的destroy()");}}

2、創建BeanFactoryPostProcessor 的實現實例

public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {public MyBeanFactoryPostProcessor() {super();System.out.println(DateUtil.getTimeNow() + "調用BeanFactoryPostProcessor構造方法");}@Overridepublic void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用BeanFactoryPostProcessor的postProcessBeanFactor(),[" + configurableListableBeanFactory + "]");} }

3、創建InstantiationAwareBeanPostProcessorAdapter實現實例

首先看一下UML圖，了解一下跟BeanPostProcessor的關系：

然后接著去實例化InstantiationAwareBeanPostProcessorAdapter

public class MyInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter {public MyInstantiationAwareBeanPostProcessor(){super();System.out.println(DateUtil.getTimeNow() + "調用InstantiationAwareBeanPostProcessor構造方法");}@Overridepublic Object postProcessBeforeInstantiation(Class<?> aClass, String s) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用InstantiationAwareBeanPostProcessor的postProcessBeforeInstantiation(),[" + s + "]");return null;}@Overridepublic boolean postProcessAfterInstantiation(Object o, String s) throws BeansException {boolean resule = true;System.out.println(DateUtil.getTimeNow() + "調用InstantiationAwareBeanPostProcessor的postProcessAfterInstantiation(),[" + s + "], 返回: "+ resule);return resule;}@Overridepublic PropertyValues postProcessPropertyValues(PropertyValues propertyValues, PropertyDescriptor[] propertyDescriptors, Object o, String s) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用InstantiationAwareBeanPostProcessor的postProcessPropertyValues(),[" + s + "]");return propertyValues;} }

4、創建BeanPostProcessor實現實例

public class MyBeanPostProcess implements BeanPostProcessor {public MyBeanPostProcess(){super();System.out.println(DateUtil.getTimeNow() + "調用BeanPostProcess構造方法");}@Overridepublic Object postProcessBeforeInitialization(Object o, String s) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用BeanPostProcess的postProcessBeforeInitialization(),[" + s + "]");return o;}@Overridepublic Object postProcessAfterInitialization(Object o, String s) throws BeansException {System.out.println(DateUtil.getTimeNow() + "調用BeanPostProcess的postProcessAfterInitialization(),[" + s + "]");return o;} }

5、將實例注冊到Spring中

將以上幾個實例注冊到Spring中，然后進行測試

<!-- 注入實例化的BeanFactoryPostProcessor--><bean class="com.leo.model.MyBeanFactoryPostProcessor"></bean><!-- 注入實例化的BeanPostProcessor --><bean class="com.leo.model.MyBeanPostProcess"></bean><!-- 注入實例化的InstantiationAwareBeanPostProcessor --><bean class="com.leo.model.MyInstantiationAwareBeanPostProcessor"></bean><!-- 手動定義一個bean --><bean id="userInfo" name="userInfo2" class="com.leo.model.UserInfo" init-method="myInit" destroy-method="myDestroy"><property name="id" value="1"></property><property name="name" value="張颯"></property><property name="age" value="18"></property></bean>

6、測試代碼

private static final String CLASS_PATH_RESOURCE = "applicationContext-test.xml";@Testpublic void classPathXmlApplicationContextTest() throws InterruptedException {ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext(CLASS_PATH_RESOURCE);UserInfo userInfo = (UserInfo) applicationContext.getBean("userInfo");System.out.println(userInfo);TimeUnit.SECONDS.sleep(3);//模擬業務運行applicationContext.registerShutdownHook();//銷毀容器}

7、運行日志

[2020-02-24 11:11:35.596] 調用BeanFactoryPostProcessor構造方法 [2020-02-24 11:11:35.644] 調用BeanFactoryPostProcessor的postProcessBeanFactor(),[org.springframework.beans.factory.support.DefaultListableBeanFactory@4dfa3a9d: defining beans [com.leo.model.MyBeanFactoryPostProcessor#0,com.leo.model.MyBeanPostProcess#0,com.leo.model.MyInstantiationAwareBeanPostProcessor#0,userInfo]; root of factory hierarchy] [2020-02-24 11:11:35.649] 調用BeanPostProcess構造方法 [2020-02-24 11:11:35.650] 調用InstantiationAwareBeanPostProcessor構造方法 [2020-02-24 11:11:35.671] 調用InstantiationAwareBeanPostProcessor的postProcessBeforeInstantiation(),[userInfo] [2020-02-24 11:11:35.672] 調用UserInfo構造方法 [2020-02-24 11:11:35.672] 調用InstantiationAwareBeanPostProcessor的postProcessAfterInstantiation(),[userInfo], 返回: true [2020-02-24 11:11:35.734] 調用InstantiationAwareBeanPostProcessor的postProcessPropertyValues(),[userInfo] [2020-02-24 11:11:35.773] 調用UserInfo賦值屬性的setId() [2020-02-24 11:11:35.774] 調用UserInfo賦值屬性的setName() [2020-02-24 11:11:35.774] 調用UserInfo賦值屬性的setAge() [2020-02-24 11:11:35.775] 調用BeanNameAware的setBeanName() [2020-02-24 11:11:35.775] 調用BeanClassLoaderAware的setBeanClassLoader() [2020-02-24 11:11:35.777] 調用BeanFactoryAware的setBeanFactory() [2020-02-24 11:11:35.779] 調用EnvironmentAware的setEnvironment() [2020-02-24 11:11:35.780] E:\WorkSpace\Git\spring-framework-learning-example\chapter-4-springmvc-sourcecode-analysis [2020-02-24 11:11:35.780] 設置系統參數System.id=springtest [2020-02-24 11:11:35.781] 調用BeanClassLoaderAware的setBeanClassLoader() [2020-02-24 11:11:35.783] 調用MessageSourceAware的setMessageSource() [2020-02-24 11:11:35.783] 調用ApplicationContextAware的setApplicationContext() [2020-02-24 11:11:35.784] 獲取系統參數System.id=springtest [2020-02-24 11:11:35.785] 調用BeanPostProcess的postProcessBeforeInitialization(),[userInfo] [2020-02-24 11:11:35.787] 調用InitializingBean的afterPropertiesSet() [2020-02-24 11:11:35.788] 調用UserInfo的myInit()方法 [2020-02-24 11:11:35.789] 調用BeanPostProcess的postProcessAfterInitialization(),[userInfo] [2020-02-24 11:11:35.818] 調用UserInfo賦值屬性的toString() [2020-02-24 11:11:35.819] UserInfo{id=1, name='張颯', gender='null', age='18', remarks='null'} [2020-02-24 11:11:38.833] 調用DisposableBean賦值屬性的destroy() [2020-02-24 11:11:38.834] 調用UserInfo的myDestroy()方法

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