Springboot startup error bean cannot be found, how to solve it

Springboot startup error reporting bean not found solution

Error report example:

1.Failed to configure a DataSource: ‘url’ attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class.

Solution:

1. It does not exist, just add it

2. The class exists, but spring has not scanned it. Pay attention to the location of the startup class, springboot By default, the subpackages and classes in the directory where the startup class is located are scanned, as shown in Figure 1.2 below. In addition, you can use the @componentScan annotation to specify the package to be scanned: Example @componentScan ({"xxx.xx", "xxx.xx"})

2. Due to the bean The relationship between loading order and configuration files

1. Please refer to the following blog post

https://www.yisu.com/article/222850.htm

https:// www.yisu.com/article/190698.htm

https://www.yisu.com/article/229466.htm

Supplement: Springboot startup error and other files have wrong versions 61.0, should be 52.0

Error reported when starting the Springboot project

java: Unable to access org.springframework.boot.SpringApplication

Wrong class file: /D:/Maven/apache-maven -3.6.3/repository/org/springframework/boot/spring-boot/3.0.0/spring-boot-3.0.0.jar!/org/springframework/boot/SpringApplication.class

Class file has wrong version 61.0, should be 52.0
Please delete the file or make sure it is in the correct classpath subdirectory.

Reason

SpringBoot uses 3.0 or above, because Spring's official release supports at least JDK17 starting from Spring6 and SpringBoot3.0, so only SpringBoot Just lower the version to below 3.0.

Reduce the SpringBoot version to below 3.0. The version is optional, just refresh Maven and restart.

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