最近一直在研究Spring Boot。从GitHub上下载了一个my-Blog源码，一边看，一边自己尝试去实现，结果掉在坑了，研究了近一周才爬出来，特地来这博客园记录下来，一是避免自己在放这样的错误，二是希望看到的朋友能有所帮助，毕竟我在网上查了很多资料，答案基本上千篇一律，并不能解决我的问题。
先说问题：我在Controller层中引用Service层的实现类，报错，错误代码如下：
2020-06-15 22:49:45.094 ERROR 1552 --- [nio-8081-exec-6] o.a.c.c.C.[.[.[/].[dispatcherServlet] : 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.example.mydemo.service.AdminUserService.login] with root cause org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.example.mydemo.service.AdminUserService.login at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:235) ~[mybatis-3.5.4.jar:3.5.4] at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:53) ~[mybatis-3.5.4.jar:3.5.4] at org.apache.ibatis.binding.MapperProxy.lambda$cachedInvoker$0(MapperProxy.java:107) ~[mybatis-3.5.4.jar:3.5.4] at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_151] at org.apache.ibatis.binding.MapperProxy.cachedInvoker(MapperProxy.java:94) ~[mybatis-3.5.4.jar:3.5.4] at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:85) ~[mybatis-3.5.4.jar:3.5.4] at com.sun.proxy.$Proxy66.login(Unknown Source) ~[na:na] at com.example.mydemo.controller.admin.AdminController.login(AdminController.java:45) ~[classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_151] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_151] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_151] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_151] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:215) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:142) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:998) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:901) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:875) ~[spring-webmvc-5.1.2.RELEASE.jar:5.1.2.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:770) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.12.jar:9.0.12] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_151] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_151] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.12.jar:9.0.12] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]
总的来说就是绑定语句无效，并未找到 com.example.mydemo.service.AdminUserService.login此方法。我从网上百度一下，看到大多数都是再讲Mapper.xml设置错误导致，需要排查：
- 检查xml文件所在package名称是否和Mapper interface所在的包名一一对应；
- 检查xml的namespace是否和xml文件的package名称一一对应；
- 检查方法名称是否对应；
但我看了很多遍，我的程序都没有这些问题，并且我在Test中测试Mapper时可以用的。
@SpringBootTest class MydemoApplicationTests { @Autowired AdminUserMapper adminUserMapper; @Resource TestService testService; @Test void TestInsert(){ AdminUser adminUser =new AdminUser(); adminUser.setAdminUserId(5); adminUser.setLocked(Byte.parseByte("1")); adminUser.setLoginPassword("123"); adminUser.setLoginUserName("zzc"); adminUser.setNickName("BigBang"); adminUserMapper.insert(adminUser); } @Test void get(){ AdminUser get= adminUserMapper.login("zzc","123"); System.out.println(get); } @Test void TestMyService(){ testService.Test(); } }
2020-06-15 22:59:08.234 INFO 10652 --- [ main] c.example.mydemo.MydemoApplicationTests : Starting MydemoApplicationTests on LAPTOP-MFBL0MLV with PID 10652 (started by zc in D:Lab_JavaDemo) 2020-06-15 22:59:08.236 INFO 10652 --- [ main] c.example.mydemo.MydemoApplicationTests : No active profile set, falling back to default profiles: default 2020-06-15 22:59:10.117 INFO 10652 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' 2020-06-15 22:59:10.814 INFO 10652 --- [ main] c.example.mydemo.MydemoApplicationTests : Started MydemoApplicationTests in 2.776 seconds (JVM running for 4.072) 2020-06-15 22:59:11.102 INFO 10652 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2020-06-15 22:59:11.287 INFO 10652 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. AdminUser{adminUserId=1, loginUserName='zzc', loginPassword='123', nickName='BigBang', locked=0} 2020-06-15 22:59:11.356 INFO 10652 --- [ Thread-2] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor' 2020-06-15 22:59:11.357 INFO 10652 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown initiated... 2020-06-15 22:59:11.359 INFO 10652 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown completed. Process finished with exit code 0
可以看到get()方法是可以使用adminUserMapper的，也就是说Mapper的注入是没有问题的。此外还写了一个TestService，里面不涉及任何Mapper相关的东西，还是报这个错误。也就是说我的问题原因和Mapper并没有关系，至少不是上述这三点导致的。
问题还是出现再Service层里，我的Service层代码如下：
package com.example.mydemo.service; import com.example.mydemo.entity.AdminUser; public interface AdminUserService { AdminUser login(String userName, String password); /** * 获取用户信息 * * @param loginUserId * @return */ AdminUser getUserDetailById(Integer loginUserId); /** * 修改当前登录用户的密码 * * @param loginUserId * @param originalPassword * @param newPassword * @return */ Boolean updatePassword(Integer loginUserId, String originalPassword, String newPassword); /** * 修改当前登录用户的名称信息 * * @param loginUserId * @param loginUserName * @param nickName * @return */ Boolean updateName(Integer loginUserId, String loginUserName, String nickName); }
package com.example.mydemo.service.impl; import com.example.mydemo.dao.AdminUserMapper; import com.example.mydemo.entity.AdminUser; import com.example.mydemo.service.AdminUserService; import com.example.mydemo.util.MD5Util; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import javax.annotation.Resource; @Service public class AdminUserServiceImpl implements AdminUserService { @Resource private AdminUserMapper adminUserMapper; @Override public AdminUser login(String userName, String password) { String passwordMd5 = MD5Util.MD5Encode(password, "UTF-8"); System.out.println("Md5:"+passwordMd5); return adminUserMapper.login(userName, passwordMd5); } @Override public AdminUser getUserDetailById(Integer loginUserId) { return adminUserMapper.selectByPrimaryKey(loginUserId); } @Override public Boolean updatePassword(Integer loginUserId, String originalPassword, String newPassword) { AdminUser adminUser = adminUserMapper.selectByPrimaryKey(loginUserId); //当前用户非空才可以进行更改 if (adminUser != null) { String originalPasswordMd5 = MD5Util.MD5Encode(originalPassword, "UTF-8"); String newPasswordMd5 = MD5Util.MD5Encode(newPassword, "UTF-8"); //比较原密码是否正确 if (originalPasswordMd5.equals(adminUser.getLoginPassword())) { //设置新密码并修改 adminUser.setLoginPassword(newPasswordMd5); if (adminUserMapper.updateByPrimaryKeySelective(adminUser) > 0) { //修改成功则返回true return true; } } } return false; } @Override public Boolean updateName(Integer loginUserId, String loginUserName, String nickName) { AdminUser adminUser = adminUserMapper.selectByPrimaryKey(loginUserId); //当前用户非空才可以进行更改 if (adminUser != null) { //设置新密码并修改 adminUser.setLoginUserName(loginUserName); adminUser.setNickName(nickName); if (adminUserMapper.updateByPrimaryKeySelective(adminUser) > 0) { //修改成功则返回true return true; } } return false; } }
controller层中的调用如下：
package com.example.mydemo.controller.admin; import com.example.mydemo.entity.AdminUser; import com.example.mydemo.service.AdminUserService; import org.springframework.stereotype.Controller; import org.springframework.util.StringUtils; import org.springframework.web.bind.annotation.*; import javax.annotation.Resource; import javax.servlet.http.HttpSession; @Controller @RequestMapping("/admin") public class AdminController { @Resource private AdminUserService adminUserService; @GetMapping({"/login"}) public String login() { return "admin/login"; } @PostMapping(value = "/login") public String login(@RequestParam("userName") String userName, @RequestParam("password") String password, @RequestParam("verifyCode") String verifyCode, HttpSession session){ if (StringUtils.isEmpty(verifyCode)) { session.setAttribute("errorMsg", "验证码不能为空"); return "admin/login"; } if (StringUtils.isEmpty(userName) || StringUtils.isEmpty(password)) { session.setAttribute("errorMsg", "用户名或密码不能为空"); return "admin/login"; } String kaptchaCode = session.getAttribute("verifyCode") + ""; if (StringUtils.isEmpty(kaptchaCode) || !verifyCode.equals(kaptchaCode)) { session.setAttribute("errorMsg", "验证码错误"); return "admin/login"; } AdminUser adminUser = adminUserService.login(userName, password); if (adminUser != null) { session.setAttribute("loginUser", adminUser.getNickName()); session.setAttribute("loginUserId", adminUser.getAdminUserId()); //session过期时间设置为7200秒 即两小时 //session.setMaxInactiveInterval(60 * 60 * 2); return "redirect:/admin/index"; } else { session.setAttribute("errorMsg", "登陆失败"); return "admin/login"; } } }
package com.example.mydemo; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication @MapperScan("com.example.mydemo") public class MydemoApplication { public static void main(String[] args) { SpringApplication.run(MydemoApplication.class, args); } }
在网上查资料，发现有人说如果Application类包所在的位置也很关键，SpringBoot项目的Bean装配默认规则是根据Application类所在的包位置从上往下扫描！Application类是指SpringBoot项目入口类。也就是我的Service层所在的包必须在com.example.mydemo或其子包下，否则Service层中的Bean不会被扫描到，但我的程序也满足啊。
结果就在这里思索了一周都没有一点进展，直到一天我发现我的@MapperScan扫描的路径是"com.example.mydemo"。WTF!!!
我又赶快上网查了一下@MapperScan注解
作用：指定要变成实现类的接口所在的包，然后包下面的所有接口在编译之后都会生成相应的实现类
添加位置：是在Springboot启动类上面添加。
看到没，包下面所有的接口在编译后之后都会生成相应的实现类，也就是说除了我的AdminUserServiceImp外Spring Boot还注入了一个mapper实现类，当我在Controller中使用@AutoWired或@Resource获取时，获取到时这个Mapper实现类的实例，但实际上并没有真正继承AdminUserService接口，只有你在运行的时候服务器才会报错，找不到对应的方法。
于是我把Mapper扫描具体到DAO路径下，即：
package com.example.mydemo; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication @MapperScan("com.example.mydemo.dao") public class MydemoApplication { public static void main(String[] args) { SpringApplication.run(MydemoApplication.class, args); } }
修改后果然不再报错。
其实这个错误说起来还是挺简单，主要时自己对Spring Boot的注解，一些基本知识还是不够了解导致，看来以后还是要继续夯实基础啊。