java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for org.fkit

报错信息：

Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException: ### Error querying database.  Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for org.fkit.mapper.StudentMapper.selectStudent### Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for org.fkit.mapper.StudentMapper.selectStudentat org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26)at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:111)at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)at org.fkit.test.SelectStudentTest.main(SelectStudentTest.java:12)Caused by: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for org.fkit.mapper.StudentMapper.selectStudentat org.apache.ibatis.session.Configuration$StrictMap.get(Configuration.java:797)at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:631)at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:624)at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:107)... 3 more

报错来源：在mybatis中进行查询时，运行代码报错误，错误的意思时：映射语句没有org.fkit.mapper.StudentMapper.selectStudent

在我的mybatis-config.xml中配置信息是：

<mappers><mapper resource="org/fkit/mapper/UserMapper.xml"/></mappers>

并没有配置StudentMapper的映射，所以在启动程序时，mybatis不知道去哪里找持久化类的映射文件了

正确的配置是：

<mappers><mapper resource="org/fkit/mapper/UserMapper.xml"/><mapper resource="org/fkit/mapper/StudentMapper.xml"/></mappers>

遇到这样的错误，不仅仅是映射文件没有配置，总的来说：

1、mapper.xml中没有加入namespace 
2、mapper.xml中的方法和接口mapper的方法不对应 
3、mapper.xml没有加入到mybatis-config.xml中(即总的配置文件)，例外：配置了mapper文件的包路径的除外 
4、mapper.xml文件名和所写的mapper名称不相同。