Spring的Bean的生命週期方法執行順序測試

經過一個簡單的Maven工程來演示Spring的Bean生命週期函數的執行順序.

下面是工程的目錄結構:

 

直接貼代碼:

 

pom.xml文件內容:

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6 
 7     <groupId>com.xuebusi</groupId>
 8     <artifactId>spring-test</artifactId>
 9     <version>1.0-SNAPSHOT</version>
10 
11     <dependencies>
12         <dependency>
13             <groupId>org.springframework</groupId>
14             <artifactId>spring-context</artifactId>
15             <version>4.3.12.RELEASE</version>
16         </dependency>
17 
18         <dependency>
19             <groupId>junit</groupId>
20             <artifactId>junit</artifactId>
21             <version>4.12</version>
22             <scope>test</scope>
23         </dependency>
24     </dependencies>
25 
26 </project>

 

beans.xml配置文件:

該配置文件主要用於演示init-method和destory-method兩個方法的執行時機.

1 <?xml version="1.0" encoding="UTF-8"?>
2 <beans xmlns="http://www.springframework.org/schema/beans"
3  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4  xmlns:context="http://www.springframework.org/schema/context"
5  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
6 
7     <context:component-scan base-package="com.xuebusi"></context:component-scan>
8     <bean id="userService" class="com.xuebusi.service.UserService" init-method="init" destroy-method="destory"/>
9 </beans>

 

SpringBeanPostProcessor類:

這個類繼承了InstantiationAwareBeanPostProcessorAdapter類,重寫了它的一些和Bean的實例化以及初始化有關的生命週期方法.

可是這些方法是針對Spring容器中的全部Bean的,因此加了個if判斷,由於這裏只是演示userService這個Bean的生命週期.

 1 import org.springframework.beans.BeansException;  2 import org.springframework.beans.PropertyValues;  3 import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;  4 import org.springframework.stereotype.Component;  5 
 6 import java.beans.PropertyDescriptor;  7 
 8 @Component  9 public class SpringBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter { 10 
11  @Override 12     public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException { 13         if ("userService".equals(beanName)) { 14             System.out.println(">>>> postProcessBeforeInstantiation"); 15  } 16         return super.postProcessBeforeInstantiation(beanClass, beanName); 17  } 18 
19  @Override 20     public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException { 21         if ("userService".equals(beanName)) { 22             System.out.println(">>>> postProcessAfterInstantiation"); 23  } 24         return super.postProcessAfterInstantiation(bean, beanName); 25  } 26 
27  @Override 28     public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException { 29         if ("userService".equals(beanName)) { 30             System.out.println(">>>> postProcessPropertyValues"); 31  } 32         return super.postProcessPropertyValues(pvs, pds, bean, beanName); 33  } 34 
35  @Override 36     public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { 37         if ("userService".equals(beanName)) { 38             System.out.println(">>>> postProcessBeforeInitialization"); 39  } 40         return super.postProcessBeforeInitialization(bean, beanName); 41  } 42 
43  @Override 44     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { 45         if ("userService".equals(beanName)) { 46             System.out.println(">>>> postProcessAfterInitialization"); 47  } 48         return super.postProcessAfterInitialization(bean, beanName); 49  } 50 }

 

UserService類:

這就是要演示的Bean,讓它實現Spring的InitializingBean接口來測試afterPropertiesSet方法, 實現BeanNameAware接口來測試setBeanName方法,實現BeanFactoryAware接口來測試setBeanFactory方法.

 1 import org.springframework.beans.BeansException;  2 import org.springframework.beans.factory.BeanFactory;  3 import org.springframework.beans.factory.BeanFactoryAware;  4 import org.springframework.beans.factory.BeanNameAware;  5 import org.springframework.beans.factory.InitializingBean;  6 import org.springframework.stereotype.Service;  7 
 8 import javax.annotation.PostConstruct;  9 import javax.annotation.PreDestroy; 10 
11 @Service 12 public class UserService implements InitializingBean, BeanNameAware, BeanFactoryAware { 13 
14     private String userName; 15 
16     public UserService() { 17         System.out.println(">>>> UserService"); 18  } 19 
20     public String getUserName() { 21         return userName; 22  } 23 
24     public void setUserName(String userName) { 25         this.userName = userName; 26  } 27 
28  @PostConstruct 29     public void postConstruct() { 30         System.out.println(">>>> postConstruct"); 31  } 32 
33  @PreDestroy 34     public void preDestroy() { 35         System.out.println(">>>> preDestroy"); 36  } 37 
38     public void init() { 39         System.out.println(">>>> init"); 40  } 41 
42     public void destory() { 43         System.out.println(">>>> destory"); 44  } 45 
46     public void setBeanFactory(BeanFactory beanFactory) throws BeansException { 47         System.out.println(">>>> setBeanFactory"); 48  } 49 
50     public void setBeanName(String s) { 51         System.out.println(">>>> setBeanName"); 52  } 53 
54     public void afterPropertiesSet() throws Exception { 55         System.out.println(">>>> afterPropertiesSet"); 56  } 57 }

 

AppTest類:

該類經過junit測試方法來啓動一個Spring容器,並從容器中獲取userService這個Bean對象.最後調用close方法銷燬Spring容器.

 1 import com.xuebusi.service.UserService;  2 import org.junit.Test;  3 import org.springframework.context.support.ClassPathXmlApplicationContext;  4 
 5 public class AppTest {  6 
 7  @Test  8     public void run() {  9         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml"); 10         UserService userService = context.getBean("userService", UserService.class); 11         userService.setUserName("蒼井空"); 12         String userName = userService.getUserName(); 13  System.out.println(userName); 14  context.close(); 15  } 16 }

 

 運行AppTest的測試方法run()而後觀察控制檯,日誌展現出了"userService"這個Bean的生命週期函數執行順序:

 1 >>>> postProcessBeforeInstantiation  2 >>>> UserService  3 >>>> postProcessAfterInstantiation  4 >>>> postProcessPropertyValues  5 >>>> setBeanName  6 >>>> setBeanFactory  7 >>>> postProcessBeforeInitialization  8 >>>> postConstruct  9 >>>> afterPropertiesSet 10 >>>> init 11 >>>> postProcessAfterInitialization 12 蒼井空 13 >>>> preDestroy 14 >>>> destory

 

總結一個Bean的生命週期方法執行順序:

1. 實例化前 postProcessBeforeInstantiation() 2. 構造方法 構造方法 3. 實例化後 postProcessAfterInstantiation() 4. 設置屬性 postProcessProperties() 5. 設置Bean名稱 setBeanName() 6. 設置BeanFactory setBeanFactory() 7. 初始化前 postProcessBeforeInitialization() 8. 構造以後 加了 @PostConstruct 的方法 9. 全部屬性賦值以後 afterPropertiesSet() 10.初始化方法              配置文件中指定的 init-method 方法 10.初始化後 postProcessAfterInitialization() 11.銷燬以前 加了 @PreDestroy 的方法 12.銷燬方法                配置文件中指定的 destroy-method 方法