mybaits 错误 Cause: java.lang.IllegalArgumentException: argument type mismatch

水深无声 2023-03-14 05:51 5阅读 0赞

# mybaits 错误 #

这是我之前的mapper.xml文件 ,报错如下

2020-05-08 19:54:04,122 [main] DEBUG [com.ujiuye.mapper.UserMapper.selectUserById] - ==>  Preparing: SELECT u.user_id,u.username,u.email,u.mobile, r.role_id,r.role_name FROM sys_user u INNER JOIN sys_user_role ur ON u.user_id=ur.user_id INNER JOIN sys_role r ON ur.role_id=r.role_id WHERE u.user_id=? 
    2020-05-08 19:54:04,147 [main] DEBUG [com.ujiuye.mapper.UserMapper.selectUserById] - ==> Parameters: 1(Long)
    
    org.apache.ibatis.exceptions.PersistenceException: 
    ### Error querying database.  Cause: org.apache.ibatis.reflection.ReflectionException: Could not set property 'roles' of 'class com.ujiuye.entity.User' with value 'Role(roleId=1, roleName=超级管理员, remark=null, deptId=null, createTime=null, users=null)' Cause: java.lang.IllegalArgumentException: argument type mismatch
    ### The error may exist in com/ujiuye/mapper/UserMapper.xml
    ### The error may involve com.ujiuye.mapper.UserMapper.selectUserById
    ### The error occurred while handling results
    ### SQL: SELECT u.user_id,u.username,u.email,u.mobile,             r.role_id,r.role_name             FROM sys_user u             INNER JOIN sys_user_role  ur ON u.user_id=ur.user_id             INNER JOIN sys_role r ON ur.role_id=r.role_id             WHERE u.user_id=?
    ### Cause: org.apache.ibatis.reflection.ReflectionException: Could not set property 'roles' of 'class com.ujiuye.entity.User' with value 'Role(roleId=1, roleName=超级管理员, remark=null, deptId=null, createTime=null, users=null)' Cause: java.lang.IllegalArgumentException: argument type mismatch
    
    	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:149)
    	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140)
    	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:76)
    	... 49 more
    
    
    Process finished with exit code -1

改正后:

注意: 我改正的是 collection 标签中的 javaType 改为了 ofType

javaType属性的问题，因为这个是一对多，通过反射应该映射为List，但是使用javaType会让MyBatis认为roles属性为单个对象，所以出错，将javaType改为ofType，只是指定泛型的类型为role。