这几天准备写一个项目，其中的整合druid的时候，发现出现了下面这个错误。找了好久都没有找到。网上的各种解决方法都不对。
2018-11-07 16:26:28.940 INFO 19684 --- [nio-9999-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/ky] : Initializing Spring FrameworkServlet 'dispatcherServlet' 2018-11-07 16:26:28.941 INFO 19684 --- [nio-9999-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started 2018-11-07 16:26:28.950 INFO 19684 --- [nio-9999-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 8 ms 2018-11-07 16:26:28.970 ERROR 19684 --- [nio-9999-exec-1] com.alibaba.druid.pool.DruidDataSource : {dataSource-2} init error java.lang.NullPointerException: null at java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011) ~[na:1.8.0_181] at java.util.concurrent.ConcurrentHashMap.putIfAbsent(ConcurrentHashMap.java:1535) ~[na:1.8.0_181] at java.lang.ClassLoader.getClassLoadingLock(ClassLoader.java:463) ~[na:1.8.0_181] at org.springframework.boot.web.embedded.tomcat.TomcatEmbeddedWebappClassLoader.loadClass(TomcatEmbeddedWebappClassLoader.java:66) ~[spring-boot-2.0.6.RELEASE.jar:2.0.6.RELEASE] at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1137) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:589) ~[druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:817) [druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1229) [druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1225) [druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:90) [druid-1.1.10.jar:1.1.10] at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:151) [spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:115) [spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:78) [spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82) [mybatis-spring-1.3.2.jar:1.3.2] at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68) [mybatis-spring-1.3.2.jar:1.3.2] at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:338) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141) [mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77) [mybatis-3.4.6.jar:3.4.6] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433) [mybatis-spring-1.3.2.jar:1.3.2] at com.sun.proxy.$Proxy71.selectOne(Unknown Source) [na:na] at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:166) [mybatis-spring-1.3.2.jar:1.3.2] at com.baomidou.mybatisplus.core.override.PageMapperMethod.execute(PageMapperMethod.java:101) [mybatis-plus-core-3.0.4.jar:na] at com.baomidou.mybatisplus.core.override.PageMapperProxy.invoke(PageMapperProxy.java:64) [mybatis-plus-core-3.0.4.jar:na] at com.sun.proxy.$Proxy101.selectById(Unknown Source) [na:na] at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl.getById(ServiceImpl.java:260) [mybatis-plus-extension-3.0.4.jar:na] at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl$$FastClassBySpringCGLIB$$76535273.invoke(<generated>) [mybatis-plus-extension-3.0.4.jar:na] at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) [spring-core-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:684) [spring-aop-5.0.10.RELEASE.jar:5.0.10.RELEASE] at com.kyplatform.admin.service.impl.UserServiceImpl$$EnhancerBySpringCGLIB$$bab224f2.getById(<generated>) [classes/:na] at com.kyplatform.admin.controller.UserController.selectUserListByIdentity(UserController.java:37) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) [druid-1.1.10.jar:1.1.10] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181] 2018-11-07 16:26:28.976 ERROR 19684 --- [nio-9999-exec-1] o.a.c.c.C.[.[.[/ky].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [/ky] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: java.lang.NullPointerException ### The error may exist in com/kyplatform/admin/mapper/UserMapper.java (best guess) ### The error may involve com.kyplatform.admin.mapper.UserMapper.selectById ### The error occurred while executing a query ### Cause: java.lang.NullPointerException] with root cause java.lang.NullPointerException: null at java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011) ~[na:1.8.0_181] at java.util.concurrent.ConcurrentHashMap.putIfAbsent(ConcurrentHashMap.java:1535) ~[na:1.8.0_181] at java.lang.ClassLoader.getClassLoadingLock(ClassLoader.java:463) ~[na:1.8.0_181] at org.springframework.boot.web.embedded.tomcat.TomcatEmbeddedWebappClassLoader.loadClass(TomcatEmbeddedWebappClassLoader.java:66) ~[spring-boot-2.0.6.RELEASE.jar:2.0.6.RELEASE] at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1137) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:589) ~[druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:817) ~[druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1229) ~[druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1225) ~[druid-1.1.10.jar:1.1.10] at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:90) ~[druid-1.1.10.jar:1.1.10] at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:151) ~[spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:115) ~[spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:78) ~[spring-jdbc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82) ~[mybatis-spring-1.3.2.jar:1.3.2] at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68) ~[mybatis-spring-1.3.2.jar:1.3.2] at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:338) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141) ~[mybatis-3.4.6.jar:3.4.6] at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77) ~[mybatis-3.4.6.jar:3.4.6] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433) ~[mybatis-spring-1.3.2.jar:1.3.2] at com.sun.proxy.$Proxy71.selectOne(Unknown Source) ~[na:na] at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:166) ~[mybatis-spring-1.3.2.jar:1.3.2] at com.baomidou.mybatisplus.core.override.PageMapperMethod.execute(PageMapperMethod.java:101) ~[mybatis-plus-core-3.0.4.jar:na] at com.baomidou.mybatisplus.core.override.PageMapperProxy.invoke(PageMapperProxy.java:64) ~[mybatis-plus-core-3.0.4.jar:na] at com.sun.proxy.$Proxy101.selectById(Unknown Source) ~[na:na] at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl.getById(ServiceImpl.java:260) ~[mybatis-plus-extension-3.0.4.jar:na] at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl$$FastClassBySpringCGLIB$$76535273.invoke(<generated>) ~[mybatis-plus-extension-3.0.4.jar:na] at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:684) ~[spring-aop-5.0.10.RELEASE.jar:5.0.10.RELEASE] at com.kyplatform.admin.service.impl.UserServiceImpl$$EnhancerBySpringCGLIB$$bab224f2.getById(<generated>) ~[classes/:na] at com.kyplatform.admin.controller.UserController.selectUserListByIdentity(UserController.java:37) ~[classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.10.RELEASE.jar:5.0.10.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) ~[druid-1.1.10.jar:1.1.10] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.10.RELEASE.jar:5.0.10.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]
最后经过一番思考，数据库连接url,driver,username,passwrod这些都没有错，更没有出现空格，可是就是出现这样的错误。再仔细看了下application.yml文件，我发现还真的是这里的错误，先来看下原始的application.yml文件
# DataSource Config spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://127.0.0.1:3306/kyplatform?characterEncoding=utf8 username: root password: ****** # 下面为连接池的补充设置，应用到上面所有数据源中 # 初始化大小，最小，最大 druid: initialSize: 5 minIdle: 5 maxActive: 20 # 配置获取连接等待超时的时间 maxWait: 60000 # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 timeBetweenEvictionRunsMillis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 minEvictableIdleTimeMillis: 300000 validationQuery: SELECT 1 FROM DUAL testWhileIdle: true testOnBorrow: false testOnReturn: false # 打开PSCache，并且指定每个连接上PSCache的大小 poolPreparedStatements: true maxPoolPreparedStatementPerConnectionSize: 20 # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙 #filters: stat,wall,log4j # 通过connectProperties属性来打开mergeSql功能；慢SQL记录 connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 # 合并多个DruidDataSource的监控数据 useGlobalDataSourceStat: true # web-stat-filter: # enabled: false # Logger Config logging: level: com.baomidou.mybatisplus.samples.quickstart: debug mybatis-plus: global-config: db-config: db-type: MYSQL capital-mode: false #开启大写命名 column-like: true #开启 LIKE 查询
再来看下修改后的application.yml文件
# DataSource Config spring: datasource: type: com.alibaba.druid.pool.DruidDataSource # 下面为连接池的补充设置，应用到上面所有数据源中 # 初始化大小，最小，最大 druid: driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://127.0.0.1:3306/kyplatform?characterEncoding=utf8 username: root password: ****** initialSize: 5 minIdle: 5 maxActive: 20 # 配置获取连接等待超时的时间 maxWait: 60000 # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 timeBetweenEvictionRunsMillis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 minEvictableIdleTimeMillis: 300000 validationQuery: SELECT 1 FROM DUAL testWhileIdle: true testOnBorrow: false testOnReturn: false # 打开PSCache，并且指定每个连接上PSCache的大小 poolPreparedStatements: true maxPoolPreparedStatementPerConnectionSize: 20 # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙 #filters: stat,wall,log4j # 通过connectProperties属性来打开mergeSql功能；慢SQL记录 connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 # 合并多个DruidDataSource的监控数据 useGlobalDataSourceStat: true # web-stat-filter: # enabled: false # Logger Config logging: level: com.baomidou.mybatisplus.samples.quickstart: debug mybatis-plus: global-config: db-config: db-type: MYSQL capital-mode: false #开启大写命名 column-like: true #开启 LIKE 查询
修改后的就是把driver,url,username,password放到druid下面，这样才不出错。