springboot+mybatis+mapper 报org.apache.ibatis.binding.BindingException: Invalid bound statement (not

先贴一个我的报错信息：

 Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.lpw.dbvideo.video.service.TestService.findById] with root cause

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.lpw.dbvideo.video.service.TestService.findById
	at org.apache.ibatis.binding.MapperMethod$SqlCommand.(MapperMethod.java:227) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.binding.MapperMethod.(MapperMethod.java:49) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:65) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:58) ~[mybatis-3.4.6.jar:3.4.6]
	at com.sun.proxy.$Proxy111.findById(Unknown Source) ~[na:na]
	at com.lpw.dbvideo.video.controller.VideoController.findById(VideoController.java:41) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:873) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:858) ~[spring-webmvc-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.11.RELEASE.jar:5.0.11.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_101]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_101]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.35.jar:8.5.35]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]

报这个错误，网络上已经有很多的解决办法，相信你都已经排查过了，无非是包的扫描路径，有的用的是xml，方法名对应之类的。

我用的是注解，没有，所以关于xml排查都没用。

说说我的解决历程，刚开始，我的启动类

@SpringBootApplication
@MapperScan("com.lpw.dbvideo")
public class DbvideoApplication {

	public static void main(String[] args) {
		SpringApplication.run(DbvideoApplication.class, args);
	}
}

我的项目结构

serviceImpl实现类上面加注解@Service，sql语句检查都没有错。

继续排查，发现方法根本没有走到，service层就报了错，转而解决是不是service层注入报错无果。因为不只是一个dao，如果直接指定扫描某一个dao会报错，一直没尝试，花费了半天，第二天早上没办法了，把其他注释掉，尝试。直接指定到dao层，即

@MapperScan("com.lpw.dbvideo.video.dao")这个时候发现程序正常了。归根结底还是这个扫描问题。但我的mapper不是都在一个dao下呀。后来查到可以写多个

@MapperScan({"com.lpw.dbvideo.user.dao","com.lpw.dbvideo.video.dao"}) 

如果如果mapper类没有在Spring Boot主程序可以扫描的包或者子包下面，可以使用如下方式进行配置

@MapperScan({"com.lpw.dbvideo*.dao","com.lpw.dbvideo*.dao"}) 

当然在也可以写，

最后我选择了第二种写法

@MapperScan({"com.lpw.dbvideo*.dao"}) 

按理说，@MapperScan 是扫描指定的文件夹下，及其所有子文件的，刚开始我的也是可以的，但不知道为什么突然就不可以了，现在也没弄懂，有知道的希望评论告下~,当然也可能仅仅针对我自己，希望对你有所帮助。