今天写代码，想到了要先写个拦截器吧，不然后面的路径还要再改。 新建完类后，实现了HandlerInterceptor接口，可是却没有提示重写方法，而且还没有报错？
通过互联网查询，得知这是Java8的新特性，因为有default的修饰，所以不重写接口方法，不会报错。
可是我们需要这些方法来拦截怎么办？
可以通过IDEA的快捷键，Mac下是⌘(command)+N然后选择“Override Methods”，或者直接按 ⌃(option)+o，就可以了，然后选中要Override的Methods，就出来了。
昨天上课讲到了要开始使用Maven，由于老师是Windows OS的电脑，所以我按照老师讲解的一步一步复刻到了Mac上，可是怎么都不好使，Maven一直在报错。
我就在想，我到底是哪里环境变量配置出问题了？
Mac的环境变量配置是真的感觉不如Windows环境变量可视化方便，Mac配置环境变量可参考Java安装的文章，需要在一个“.bash_profile”文件里添加，可是我一直不知道规则是什么，到底该怎么写才对。
后来自己瞎蒙，看了看网上的，再相比于以前的改了改，终于出来了。
没想道还需要单独配置JAVA_HOME的变量，Maven才能用
今天遇到了一个很棘手的错误，密码正确，就是无法访问MySQL。
差点都要重装MySQL了。。。
仔细检查了一下，都没问题啊？数据库密码也正确，database.properties里面的数据也没有空格，配置文件里面的数据也正确，可就是无法连接数据库额。
一开始以为是权限问题？可后来从网上查到，没有人提到过权限问题，就放弃了。
后来想着，不要配置文件从database.properties获取了，直接给具体数据试试，没想到成功了。。。
附错误代码：
AbandonedObjectPool is used (org.apache.commons.dbcp.AbandonedObjectPool@370daa12)
LogAbandoned: false
RemoveAbandoned: true
RemoveAbandonedTimeout: 180
- (24256 ms) - 2021-5-8 09:14:36[DEBUG](JakartaCommonsLoggingImpl.java:46) Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@512f7f74]
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
### The error may exist in cn/smbms/dao/user/UserMapper.xml
### The error may involve cn.smbms.dao.user.UserMapper.getUserByUserCode
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:364)
at com.sun.proxy.$Proxy10.selectOne(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:159)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:43)
at com.sun.proxy.$Proxy17.getUserByUserCode(Unknown Source)
at cn.smbms.service.user.impl.UserServiceImpl.findUserByUserCode(UserServiceImpl.java:29)
at cn.smbms.service.user.impl.UserServiceImpl$$FastClassBySpringCGLIB$$bcc37683.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:700)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:633)
at cn.smbms.service.user.impl.UserServiceImpl$$EnhancerBySpringCGLIB$$3d144642.findUserByUserCode(<generated>)
at cn.smbms.controller.LoginController.doLogin(LoginController.java:41)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:743)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:672)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:82)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:106)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:544)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:616)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:818)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1626)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
### The error may exist in cn/smbms/dao/user/UserMapper.xml
### The error may involve cn.smbms.dao.user.UserMapper.getUserByUserCode
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:107)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:62)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:354)
... 62 more
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:80)
at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:66)
at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:271)
at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:69)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:56)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
... 69 more
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'toby'@'localhost' (using password: YES))
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1225)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
... 79 more
Caused by: java.sql.SQLException: Access denied for user 'toby'@'localhost' (using password: YES)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4187)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4119)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:927)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1709)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1252)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2483)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2516)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2301)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:294)
at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1247)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1221)
... 82 more
null前几天遇到的一个错误，Parameter index out of range (7 > number of parameters, which is 6).
利用搜索引擎查询了一下，意识到这是我的SQL预编译语句可能有问题，只有6个问号，可是提供了7个参数。
修正一下SQL语句就可以了，以后还是要细心，原来在清理’时出问题了。
这几天学到了Spring框架，老师给了几个很久以前的jar包，想体验一下最新的，于是就想去网上找一找。
由于Spring框架的jar包下载地址不太好找，特整理一下，以便以后使用。
Spring的官网是spring.io
Spring所需要的文件，下载仓库：repo.spring.io
一个更简洁Spring框架下载地址：https://repo.spring.io/release/org/springframework/spring/
调试代码怎么也无法写入数据库，一直报错“Unknown column ‘XXX’ in ‘field list’”。
通过互联网查了一下，好像是数据库没有对应的列。
可是数据库没问题啊？
仔细查了一下DAO层的SQL代码，SQL语句也没问题啊？
突然发现，SQL语句插入的表不对，不知道什么时候改成添加到别的表了。
把插入的表名改对就行了。
以后再出这种问题，要先检查数据库，然后检查SQL代码
以前写好的角色信息查询，今天突然就不好用了，想要关键字查询，一查就报错，显示rst为null。正感觉又要花大力气解决一下的时候，一步步查SQL，突然加了一个空格解决了。。。
原来是这样的SQL语句拼接，
然后能随意上下翻页，以及关键字查询了。
SQL语句拼接的话，一定要注意空格，如果全都“凑”到一起去的话，是会报错的。
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.toleey.smbms.dao.provider.ProviderDao.getAllProviderList
### Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.toleey.smbms.dao.provider.ProviderDao.getAllProviderList
刚刚写作业的时候，想进行测试，关于查询其他表的操作，可是一直报错。
仔细看了看，和课上写的几乎一样，可就是报错，不知道为什么。
从网上搜了搜相关的，尝试把SqlSessionTemplate的selectLsit方法里面的statement内容删掉Path，只留下了方法名，终于成功了。
应该是这个地方应该要与ProviderMapper里面对应的select标签的id一样，才可以，要不然找不到。
今天入门Spring与MyBatis的融合，但使用Eclipse新建Web Dynamic Project一直不是默认的新建样子，于是决定使用IDEA写。
写着写着，遇到了错误，因为身边同学都是Eclipse，所以就上网查询。
终于了解到，原来是resources文件夹没有标注为Resources Root，因为在IDEA中我是手动建立的，所以需要标注。
用Eclipse开发JavaWeb项目是，有时会忘记勾选”Generate web.xml deployment descriptor “
可是等到用的时候，才发现没有，想要重新创建该怎么弄呢？
选中项目—>右键，Java EE Tools—>Generate Deployment Descriptor Stub
就会出现了。
