1.描述问题：
第一天已经运行成功一次，第二天重新打开就出错了，错误是springboot启动不了。
2.App代码
package com.czs;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.czs.mapper") //@MapperScan 用户扫描MyBatis的Mapper接口
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
3.报错代码
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-05-01 17:47:29.617 ERROR 12884 --- [ main] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userControllor': Unsatisfied dependency expressed through field 'userservice'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImpl': Unsatisfied dependency expressed through field 'usermapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [E:\eclipse_mars\文件\SpringBoot-springmvc-mabatis\target\classes\com\czs\mapper\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Generic.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.cj.jdbc.Driver
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:882) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
at com.czs.App.main(App.java:11) [classes/:na]
，找不到到这个驱动类，全盘搜索下类,或者在maven里面看下引入了mysql-connector-java这个jar包没有，版本需要8.0以上
