method is called. This will happen automatically if Bean implement the interface. setBeanName(String beanName) BeanNameAware The following is a detailed explanation of when when, who and how to call:

setBeanName() Who calls ?

Spring IOC (control reversal) container

call setBeanName().

When Bean is initialized and registered to the Spring context, the Spring container checks whether Bean has implemented the interface. If it is implemented, Spring will automatically call the method and transmit the setBeanName() Bean name

Bean name BeanNameAware. setBeanName() When is it called?

setBeanName() Bean initialization stage

1. After

   Bean instantiated, But In any other initialized callback

   (such as

   or setBeanName()) before call. @PostConstruct InitializingBean.afterPropertiesSet() The order of the event :

   The surrounding life cycle events are shown below:

2. Spring container instantiated bean. Spring determines the name of the bean from the configuration (such as

   or

   ). setBeanName()

   If bean is implemented, the
   method is called, and the name of the bean is passed as a parameter.
   Relying on injection and other initialization operations.
   2. @Bean @Component
   3. BeanNameAware How to call Spring setBeanName()?
   Bean's registration period
:

application context setBeanName(). When registering Bean, it associates its name with Bean (explicitly defined or automatically generated).

1. Check :

   During the initialization period, Spring will check whether bean has achieved . If so, Spring will automatically call the method.

2. Pass the name of the bean : BeanNameAware The name of the bean passed to is:

   BeanNameAware The name specified in the configuration (setBeanName() or

   ).
3. The default name generated by Spring (e.g., class name, first letter sketch:

   corresponding ).

   setBeanName()

   Simplified code process
   • @Bean(name = "myBean") The following is the way Spring calls @Component("myBean") in the Bean's life cycle:

   // Spring容器初始化（偽代碼）
   public class BeanFactory {
       public Object createBean(Class<?> beanClass, String beanName) {
           // 步驟1：實(shí)例化bean
           Object bean = instantiateBean(beanClass);
   
           // 步驟2：檢查bean是否實(shí)現(xiàn)了BeanNameAware
           if (bean instanceof BeanNameAware) {
               // 步驟3：調(diào)用setBeanName()并傳遞bean的名稱
               ((BeanNameAware) bean).setBeanName(beanName);
           }
   
           // 步驟4：繼續(xù)進(jìn)行依賴注入和其他生命周期回調(diào)
           injectDependencies(bean);
           initializeBean(bean);
   
           return bean;
       }
   }

   ---

   Practice example

   bean definition

   @Configuration
   public class AppConfig {
   
       @Bean(name = "tenantA-dataSource")
       public TenantDataSource tenantADataSource() {
           return new TenantDataSource();
       }
   }

   bean implementation

   import org.springframework.beans.factory.BeanNameAware;
   
   public class TenantDataSource implements BeanNameAware {
       private String tenantName;
       private String databaseUrl;
   
       @Override
       public void setBeanName(String beanName) {
           // 從bean名稱中提取租戶名稱
           if (beanName.contains("-")) {
               this.tenantName = beanName.split("-")[0];
           } else {
               throw new IllegalArgumentException("無效的bean命名約定。預(yù)期格式：<tenantname>-dataSource");
           }
   
           // 根據(jù)租戶名稱動(dòng)態(tài)分配數(shù)據(jù)庫(kù)URL
           this.databaseUrl = "jdbc:mysql://localhost:3306/" + tenantName + "_db";
           System.out.println("setBeanName() called for: " + beanName + ", resolved tenant: " + tenantName);
       }
   
       public void connect() {
           System.out.println("Connecting to database: " + databaseUrl);
       }
   }

   Main application <主>

   import org.springframework.context.ApplicationContext;
   import org.springframework.context.annotation.AnnotationConfigApplicationContext;
   
   public class Main {
       public static void main(String[] args) {
           // 初始化Spring上下文
           ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
   
           // 獲取bean
           TenantDataSource tenantA = (TenantDataSource) context.getBean("tenantA-dataSource");
   
           // 使用bean
           tenantA.connect();
       }
   }

   Output <輸>

   <code>setBeanName() called for: tenantA-dataSource, resolved tenant: tenantA
   Connecting to database: jdbc:mysql://localhost:3306/tenantA_db</code>

   Use case

   ---

   setBeanName()

   Dynamic configuration
   :

   1. Use the name of the bean to associate (such as the attributes specific to the tenants).

      Debug

      :
   2. Add debugging or log records according to the name of the bean.
      Programming custom

      :

   Dynamically modify Bean behavior according to the Bean name.

   3. When to avoid the use of

   For most applications, it is more practical to rely on

   ---

   or external configuration.

   setBeanName() Avoid the logic too complicated by hard -coding Bean name dependencies. For this kind of situation, it is best to use an external configuration source or dynamic routing.

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