Springboot 项目 无法读取resources下的mapper文件夹的.xml文件

最开始报了一个这样的错误：意思没扫描到mapper

我在启动类上面加注解 扫描mapper

加上之后，启动项目 ，还是有报错
错误如下：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'testUserController': Unsatisfied dependency expressed through field 'db1TestUserMapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'db1TestUserMapper' defined in file [D:\2021-06-15hafeng\multi-data-source\target\classes\com\hafeng\multidatasource\mapper\db1\Db1TestUserMapper.class]: Cannot resolve reference to bean 'db1SqlSessionFactory' while setting bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'db1SqlSessionFactory' defined in class path resource [com/hafeng/multidatasource/config/DataSourceConfig1.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'db1SqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:660) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1413) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:601) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.9.jar:5.3.9]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.9.jar:5.3.9]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.5.3.jar:2.5.3]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) ~[spring-boot-2.5.3.jar:2.5.3]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434) ~[spring-boot-2.5.3.jar:2.5.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) ~[spring-boot-2.5.3.jar:2.5.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-2.5.3.jar:2.5.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332) ~[spring-boot-2.5.3.jar:2.5.3]
	at com.hafeng.multidatasource.MultiDataSourceApplication.main(MultiDataSourceApplication.java:12) ~[classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'db1TestUserMapper' defined in file [D:\2021-06-15hafeng\multi-data-source\target\classes\com\hafeng\multidatasource\mapper\db1\Db1TestUserMapper.class]: Cannot resolve reference to bean 'db1SqlSessionFactory' while setting bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'db1SqlSessionFactory' defined in class path resource [com/hafeng/multidatasource/config/DataSourceConfig1.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'db1SqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:342) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:113) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1689) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1434) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:601) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1380) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1300) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:657) ~[spring-beans-5.3.9.jar:5.3.9]
	... 20 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'db1SqlSessionFactory' defined in class path resource [com/hafeng/multidatasource/config/DataSourceConfig1.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'db1SqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1334) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:564) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:330) ~[spring-beans-5.3.9.jar:5.3.9]
	... 33 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'db1SqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.9.jar:5.3.9]
	... 43 common frames omitted
Caused by: org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.mybatis.spring.SqlSessionFactoryBean.buildSqlSessionFactory(SqlSessionFactoryBean.java:612) ~[mybatis-spring-2.0.5.jar:2.0.5]
	at org.mybatis.spring.SqlSessionFactoryBean.afterPropertiesSet(SqlSessionFactoryBean.java:490) ~[mybatis-spring-2.0.5.jar:2.0.5]
	at org.mybatis.spring.SqlSessionFactoryBean.getObject(SqlSessionFactoryBean.java:632) ~[mybatis-spring-2.0.5.jar:2.0.5]
	at com.hafeng.multidatasource.config.DataSourceConfig1.db1SqlSessionFactory(DataSourceConfig1.java:38) ~[classes/:na]
	at com.hafeng.multidatasource.config.DataSourceConfig1$$EnhancerBySpringCGLIB$$7c2a9ed0.CGLIB$db1SqlSessionFactory$1(<generated>) ~[classes/:na]
	at com.hafeng.multidatasource.config.DataSourceConfig1$$EnhancerBySpringCGLIB$$7c2a9ed0$$FastClassBySpringCGLIB$$af3156ee.invoke(<generated>) ~[classes/:na]
	at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.3.9.jar:5.3.9]
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) ~[spring-context-5.3.9.jar:5.3.9]
	at com.hafeng.multidatasource.config.DataSourceConfig1$$EnhancerBySpringCGLIB$$7c2a9ed0.db1SqlSessionFactory(<generated>) ~[classes/:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.9.jar:5.3.9]
	... 44 common frames omitted
Caused by: java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist
	at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:187) ~[spring-core-5.3.9.jar:5.3.9]
	at org.mybatis.spring.SqlSessionFactoryBean.buildSqlSessionFactory(SqlSessionFactoryBean.java:608) ~[mybatis-spring-2.0.5.jar:2.0.5]
	... 57 common frames omitted

Disconnected from the target VM, address: '127.0.0.1:56107', transport: 'socket'

Process finished with exit code 1

原因是我原先单层路径
我改了多层路径忘改扫描xml文件位置了
原因：

解决：

改了之后还报错，找了很多办法最终找到了错在哪里
主要看这句话

Failed to parse mapping resource: 'class path resource [classpath*:/mapper/db1/*.xml]'; nested exception is java.io.FileNotFoundException: class path resource [classpath*:/mapper/db1/*.xml] cannot be opened because it does not exist

类路径资源：classpath*:/mapper/db1/*.xml不能打开xml，因为它不存在
没道理啊？我的文件目录

resources下明明就有这个mapper文件夹，和这个xml文件，为什么会找不到呢
解决思路：
首先，确定了文件名和application,properties下的路径名没错
其次，检查一下测试的方法

问题可能主要出现在配置mapper上，所以检查SessionFactoryConfiguration
关于sqlSessionFactory: https://blog.csdn.net/u013412772/article/details/73648537.
关于sqlSeesionFactoryBean：
https://blog.csdn.net/u013412772/article/details/73648537.
仔细检查路径和类基本上都没错，直到看到这行：

bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResource("classpath*:/mapper/db1/*.xml"));

sqlSessionFactoryBean调用的方法中setMapperLocations可能是导致读取不到mapper资源的原因
关于PathMatchingResourcePatternResolver :
https://www.cnblogs.com/loveLands/articles/9863195.html.
果然getResource 和 getResources不同
getResource()：
1.从类的根路径下获取文件
getResources():
1.获取所有类路径下的指定文件
可以通过classpath前缀指定，从所有的类路径下获取指定文件，与classpath前缀的区别是classpath前缀只能获取当类路径下的资源文件，而classpath前缀可以获取所有类路径下的资源文件，包括jar包中的。

参考资料： https://www.cnblogs.com/jev-0987/p/12839193.html.