org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)

完整错误信息：org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.wanyu.fams.dao.BaseAreaMapper.selectByExample at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:225) ~[mybatis-3.4.5.jar:3.4.5] at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:48) ~[mybatis-3.4.5.jar:3.4.5] at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:65) ~[mybatis-3.4.5.jar:3.4.5] at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:58) ~[mybatis-3.4.5.jar:3.4.5] at com.sun.proxy.$Proxy68.selectByExample(Unknown Source) ~[na:na] at com.wanyu.fams.rest.TestController.baseArea(TestController.java:40) ~[classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar:8.5.23] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar:8.5.23] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar:8.5.23] at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]Spring Boot 项目，访问 @RestController 时遇到此错误

错误原因：

1、使用 MapperScan 注释方式整合 MyBatis，但是没有在 Dao 接口文件中以注释的方式指定 SQL，例如：import java.util.List;

import org.apache.ibatis.annotations.Select;

import com.wyl.bean.Grade;

public interface GradeMapper {

@Select("select * from grade where grade_nm=#{name}")
public List<Grade> getByGradeNm(String name);

　　@Insert("insert into grade(grade_nm,teacher_id) values(#{gradeNm},#{teacherId})")
@Options(useGeneratedKeys=true,keyColumn="id",keyProperty="id")//设置id自增长
public void save(Grade grade);
}或者在 App 类（入口类）中添加以下方法：
@Bean
@ConfigurationProperties(prefix="spring.datasource")
public DataSource dataSource() {
return new org.apache.tomcat.jdbc.pool.DataSource();
}

@Bean
public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSource());

PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();

sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:com/wanyu/fams/mapper/*Mapper.xml"));

return sqlSessionFactoryBean.getObject();
}

@Bean
public PlatformTransactionManager transactionManager() {
return new DataSourceTransactionManager(dataSource());
}

2、使用 配置文件 Mapper.xml 文件方式 namespace 填写错误：<mapper namespace="com.xxx.xxx.dao.BaseAreaMapper">需要和 dao 层接口的类名和包路径完全一致。3、dao 层接口没有添加 @Mapper 注解
另外，你可能遇到错误：
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.wan