springboot之取消starter的自動注入
starer是spring boot中一個很重要的概念,starter相當於一個模塊,它能將所需要的的依賴整合在一起並對模塊內的bean自動裝配到spring IOC容器,使用者只需要在maven中依賴相應的starter包並無需做過多的依賴即可進行開發。
一、例子
比如,我們導入了mybatis相關的依賴,但是我可能暫時沒用到數據庫,所以就沒有做數據庫相關的配置,這時候項目就會無法啓動
2020-03-08 22:13:10.396 WARN 10692 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource
[org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed;
nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate
[com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception;
nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
因爲springboot中默認的數據庫連接池是hikari,你沒有在application.properties裏面進行數據庫相關的配置的話,那麼就會無法自動裝載dataSource
Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]
那麼重點來了,如何取消相關starer的自動注入?
我們還是以數據庫的這個爲例子:
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
那麼,就需要在啓動類加上如上配置,取消DataSourceAutoConfiguration的自動注入
springbootApplication是一個組合註解,其實裏面真正實現自動注入功能的,是這個EnableAutoConfiguration註解