nested exception is org.apache.ibatis.binding.BindingException: Parameter 'problem' not found.

Mybatis报错: nested exception is org.apache.ibatis.binding.BindingException: Parameter 'problem' not found. 

原因就在于mapper，一定是传参出了问题。

百思不得其解时，突然发现，Param声明的参数名与数据库sql中的名字写的不一致了。[原来的声明@Param("question") String question ]

userMapper.xml:

 
        SELECT count(1)
        from user
        where del = 1
          and username = #{username}
          and problem = #{problem}
          and answer = #{answer}
 

UserMapper.java:

 int checkAnswer(@Param("username") String username, @Param("problem") String problem, @Param("answer") String answer);