异常一 java.lang.IllegalArgumentException: No enum constant

错误信息 （mybatis版本为3.4.6）

Caused by: org.apache.ibatis.executor.result.ResultMapException: Error attempting to get column 'statu' from result set.  Cause: java.lang.IllegalArgumentException: No enum constant com.smartfsc.dal.domain.company.po.enums.EMechanismType.NORMAL
    at org.apache.ibatis.type.BaseTypeHandler.getResult(BaseTypeHandler.java:68)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getPropertyMappingValue(DefaultResultSetHandler.java:471)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.applyPropertyMappings(DefaultResultSetHandler.java:440)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:403)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForSimpleResultMap(DefaultResultSetHandler.java:355)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:330)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:303)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:196)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
    at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:143)
    at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
    at com.sun.proxy.$Proxy116.query(Unknown Source)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)
    ... 38 more
Caused by: java.lang.IllegalArgumentException: No enum constant com.smartfsc.dal.domain.company.po.enums.EMechanismType.NORMAL
    at java.lang.Enum.valueOf(Enum.java:238)
    at org.apache.ibatis.type.EnumTypeHandler.getNullableResult(EnumTypeHandler.java:49)
    at org.apache.ibatis.type.EnumTypeHandler.getNullableResult(EnumTypeHandler.java:26)
    at org.apache.ibatis.type.BaseTypeHandler.getResult(BaseTypeHandler.java:66)
    ... 61 more

Mapper文件的配置

<result column="statu" property="status" typeHandler="org.apache.ibatis.type.EnumTypeHandler"/>

可能导致的原因

由于mybatis框架的异常信息不太友好，比较难以定位问题。枚举 A的实例映射到枚举B，转换不了。导致这个异常的原因可能是Mapper的配置文件有误。可能是与枚举A相关的Mapper配置文件有误，也可能是和枚举B有关的Mapper配置文件有误。开发中遇见了几次这个问题，记录一下。

解决方法

找出错误解决错误。不过也可以这样试试。

 将typeHandler="org.apache.ibatis.type.EnumTypeHandler" 替换为 jdbcType="VARCHAR" 试试。即
 <result column="statu" property="status"  jdbcType="VARCHAR"/>