今天，在運行springboot項目遇到了報錯，經過研究後終於發現了坑在哪裏，記錄以下，避免再次踩坑。
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APPLICATION FAILED TO START
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Description:
Field roleMapper in com.onezero.springboottest.service.impl.RoleServiceImpl required a bean of type 'com.onezero.springboottest.mapper.RoleMapper' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)
Action:
Consider defining a bean of type 'com.onezero.springboottest.mapper.RoleMapper' in your configuration.
雖然說註解都沒有遺漏，都添加到指定的地方，但是在運行應用時仍然報錯，報錯信息如下：
Field roleMapper in com.onezero.springboottest.service.impl.RoleServiceImpl required a bean of type 'com.onezero.springboottest.mapper.RoleMapper' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)
翻譯過來就是：
com.onezero.springboottest.service.impl.RoleServiceImpl中的變量roleMapper沒有找到依賴的一個com.onezero.springboottest.mapper.RoleMapper類型的實體類。
研究之後發現，問題出在引入的依賴上，注意引入的依賴是mybatis-spring-boot-starter，而不是mybatis，所以需要將pom.xml文件中引入的依賴做下修改，引入新的mybatis-spring-boot-starter依賴.
<!--<dependency>-->
<!--<groupId>org.mybatis</groupId>-->
<!--<artifactId>mybatis</artifactId>-->
<!--<version>3.4.1</version>-->
<!--</dependency>-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.1</version>
</dependency>
修改之後在試着去重啓應用，發現啓動成功了！
順利從坑裏出來！