其他开发人员已经对此类问题发表了评论。
- 如果我在参数中指定 JdbcType,MyBatis 不会覆盖 JdbcType #139 https://github.com/mybatis/mybatis-3/issues/139
我引用GitHub的评论:
@nglsatheesh MyBatis 无法强制转换/转换这些类型,除非你告诉它如何操作。
您所需要的只是一个简单的自定义类型处理程序。
public class StrToIntTypeHandler implements TypeHandler<String> {
@Override
public void setParameter(PreparedStatement ps, int i,
String parameter, JdbcType jdbcType) throws SQLException {
ps.setInt(i, Integer.parseInt(parameter));
}
// other methods are for binding query results.
}
select * from table_name where id = #{value,typeHandler=StrToIntTypeHandler}
现在,如果您要创建这样一个自定义类型处理程序:
public class Null2DateTypeHandler implements TypeHandler<Date> {
@Override
public void setParameter(PreparedStatement ps, int i, java.util.Date parameter, JdbcType jdbcType) throws SQLException {
System.err.println(String.format("ps: %s, i: %d, param: %s, type: %s", ps.toString(), i, parameter, jdbcType.toString()));
if (parameter == null) {
ps.setDate(i, null); // ??? I'm not sure. But it works.
} else {
ps.setDate(i, new java.sql.Date(parameter.getTime()));
}
}
}
并且,映射器方面:
@Select({
"<script>"
, "SELECT * FROM `employees` WHERE `hire_date` "
, " BETWEEN
, " #{dateFrom,typeHandler=*.*.*.Null2DateTypeHandler}"
, " AND"
, " #{dateTo,typeHandler=*.*.*.Null2DateTypeHandler}"
,"</script>"
})
@Results({
@Result(property = "empNo", column = "emp_no"),
@Result(property = "birthDate", column = "birth_date"),
@Result(property = "firstName", column = "first_name"),
@Result(property = "lastName", column = "last_name"),
@Result(property = "gender", column = "gender"),
@Result(property = "hireDate", column = "hire_date")
})
List<Employees> selectBetweenTypeHandler(@Param("dateFrom") Date dateFrom, @Param("dateTo") Date dateTo);
我的记录,看起来工作正常。
DEBUG [main] - ==> Preparing: SELECT * FROM `employees` WHERE `hire_date` BETWEEN ? AND ?
ps: org.apache.ibatis.logging.jdbc.PreparedStatementLogger@369f73a2, i: 1, param: null, type: OTHER
DEBUG [main] - ==> Parameters: null, null
ps: org.apache.ibatis.logging.jdbc.PreparedStatementLogger@369f73a2, i: 2, param: null, type: OTHER
DEBUG [main] - <== Total: 0