MyBatisPlus 整合 SpringBoot 遇见的问题（一）

【异常】：UnsatisfiedDependencyException: Error creating bean with name 'xxx[类]': Unsatisfied dependency expressed through field 'baseMapper';
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BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\xx\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\xx\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache   

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-04-18 16:46:43.334 [restartedMain] ERROR org.springframework.boot.SpringApplication.reportFailure(826) - Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'zoneBO': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'zoneDAO' defined in file [D:\Project\yunda\cyber\cyber-web\target\classes\com\yd\cyber\web\dao\ZoneDAO.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
    at com.yd.cyber.web.WebApplication.main(WebApplication.java:13)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'zoneDAO' defined in file [D:\Project\yunda\cyber\cyber-web\target\classes\com\yd\cyber\web\dao\ZoneDAO.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1526)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1406)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
    ... 24 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:656)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:636)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1511)
    ... 35 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:651)
    ... 48 common frames omitted
Caused by: org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:595)
    at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:430)
    at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:628)
    at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:214)
    at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$1952ec39.CGLIB$sqlSessionFactory$1(<generated>)
    at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$1952ec39$$FastClassBySpringCGLIB$$6017a70d.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
    at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$1952ec39.sqlSessionFactory(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    ... 49 common frames omitted
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Project\yunda\cyber\cyber-web\target\classes\mapper\ScanCyberMapper.xml]'. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:122)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.parse(XMLMapperBuilder.java:94)
    at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:593)
    ... 62 common frames omitted
Caused by: org.apache.ibatis.type.TypeException: Could not resolve type alias 'org.mybatis.caches.ehcache.LoggingEhcache'.  Cause: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:120)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.cacheElement(XMLMapperBuilder.java:204)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:116)
    ... 64 common frames omitted
Caused by: java.lang.ClassNotFoundException: Cannot find class: org.mybatis.caches.ehcache.LoggingEhcache
    at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:200)
    at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:89)
    at org.apache.ibatis.io.Resources.classForName(Resources.java:261)
    at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:116)
    ... 66 common frames omitted
Disconnected from the target VM, address: '127.0.0.1:63325', transport: 'socket'

Process finished with exit code 1

 【原因】：我的原因是服务解析下面路径时出现了问题，我的配置如下：同事这也却没有问题，心里真不是滋味。

mybatis-plus:
  mapper-locations: classpath*:/mapper/*Mapper.xml

【解决方案一】：直接定义为全路径

mybatis-plus:
  mapper-locations: classpath:/src/main/resources/mapper/*Mapper.xml

【解决方案二】：Maven 项目，在 pom 文件的 resource 中指定 xml 路径

<build>
  <resources>
      <resource>
          <!-- xml放在java目录下-->
          <directory>src/main/java</directory>
          <includes>
              <include>**/*.xml</include>
          </includes>
      </resource>
      <!--指定资源的位置（xml放在resources下，可以不用指定）-->
      <resource>
          <directory>src/main/resources</directory>
      </resource>
  </resources>
</build>

【解决方案三】：如果只是一个 mapper.xml 文件，直接指定也不会出现问题

mybatis-plus:
  mapper-locations: /mapper/ZoneMapper.xml

【解决方案四】： 【目前使用的方案】因为加载 *Mapper.xml 文件的时候，里面配置了二级缓存【我生成的时候不小心生成的】，这个时候，就会出现上述的问题。而且二级缓存是有缺陷的，可能会导致获取到的数据是旧数据，也就是关联的数据没有更新的问题。所以我们项目是关闭的，那么当我注释掉二级缓存之后，这个问题也就解决了。

    <!-- 开启二级缓存 -->
<!-- <cache type="org.mybatis.caches.ehcache.LoggingEhcache"/>-->