org.springframework.beans.factory.NoUniqueBeanDefinitionException 異常

• org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.atguigu.dao.BookDao' available: expected single matching bean but found 2: bookDao,bookDao2
  
      at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1180)
      at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveBean(DefaultListableBeanFactory.java:416)
      at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:349)
      at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:342)
      at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1126)
      at com.atguigu.test.IOCTest_Autowired.test01(IOCTest_Autowired.java:30)
      at java.util.ArrayList.forEach(ArrayList.java:1257)
      at java.util.ArrayList.forEach(ArrayList.java:1257)

• 解決：

  • 在其中一個 bean 上加 @Primary，使得自動配置時不報錯。

    • @Primary 讓Spring自動裝配的時候,默認使用裝配首選的bean

  • 根據 bean 的 id 去獲取 bean 對象。