mybatis custom type handler without annoations - mybatis

Question

I'm new to mybatis. I am trying to map a JDBC integer to a custom class. All the examples that I have seen on this have used annotations, is it possible to not use annotations and do this? Any example would be greatly appreciated.
Sreekanth

Answer 1

It is definitely possible and is described in general in Configuration and in Mapper sections of the documentation.
Define the handler first:
#MappedJdbcTypes(JdbcType.INTEGER)
public class MyClassHandler extends BaseTypeHandler<MyClass> {
#Override
public void setNonNullParameter(PreparedStatement ps, int i,
MyClass parameter, JdbcType jdbcType) throws SQLException {
ps.setInt(i, parameter.asInt());
}
#Override
public MyClass getNullableResult(ResultSet rs, String columnName)
throws SQLException {
int val = rs.getInt(columnName);
if (rs.wasNull())
return null;
else
return MyClass.valueOf(val);
}
#Override
public MyClass getNullableResult(ResultSet rs, int columnIndex)
throws SQLException {
int val = rs.getInt(columnIndex);
if (rs.wasNull())
return null;
else
return MyClass.valueOf(val);
}
#Override
public MyClass getNullableResult(CallableStatement cs, int columnIndex)
throws SQLException {
int val = cs.getInt(columnIndex);
if (cs.wasNull())
return null;
else
return MyClass.valueOf(val);
}
}
Then configure it in mybatis-config.xml:
<typeHandlers>
<typeHandler handler="my.company.app.MyClassHandler"/>
</typeHandlers>
Now you can use it in xml mappers.
If you have a class
class SomeTypeEntity {
private MyClass myClassField;
};
For querying the field configure handler in the resultMap like this:
<resultMap id="someMap" type="SomeTypeEntity">
<result property="myClassField" column="my_class_column" typeHandler="my.company.app.MyClassHandler"/>
</resultMap>
For insert/update use it like this:
<update id="updateSomeTypeWithMyClassField">
update some_type
set
my_class_column = #{someTypeEntity.myClassField, typeHandler=my.company.app.MyClassHandler},
</update>
for mapper method:
void updateSomeTypeWithMyClassField(#Param("someTypeEntity") SomeTypeEntity entity);