2018-05-21 23:06:10.041 ERROR 3236 --- [nio-9001-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.builder.BuilderException: Error evaluating expression ''. Cause: org.apache.ibatis.ognl.ExpressionSyntaxException: Malformed OGNL expression:  [org.apache.ibatis.ognl.ParseException: Encountered "<EOF>" at line 1, column 0.
Was expecting one of:
    ":" ...
    "not" ...
    "+" ...
    "-" ...
    "~" ...
    "!" ...
    "(" ...
    "true" ...
    "false" ...
    "null" ...
    "#this" ...
    "#root" ...
    "#" ...
    "[" ...
    "{" ...
    "@" ...
    "new" ...
    <IDENT> ...
    <DYNAMIC_SUBSCRIPT> ...
    "\'" ...
    "`" ...
    "\"" ...
    <INT_LITERAL> ...
    <FLT_LITERAL> ...
    ]] with root cause

org.apache.ibatis.ognl.ParseException: Encountered "<EOF>" at line 1, column 0.
Was expecting one of:
    ":" ...
    "not" ...
    "+" ...
    "-" ...
    "~" ...
    "!" ...
    "(" ...
    "true" ...
    "false" ...
    "null" ...
    "#this" ...
    "#root" ...
    "#" ...
    "[" ...
    "{" ...
    "@" ...
    "new" ...
    <IDENT> ...
    <DYNAMIC_SUBSCRIPT> ...
    "\'" ...
    "`" ...
    "\"" ...
    <INT_LITERAL> ...
    <FLT_LITERAL> ...

错误原因：mapper的语句里不能有注释。