MyBatis(3.2.3) - Handling enumeration types

MyBatis supports persisting enum type properties out of the box. Assume that the STUDENTS table has a column gender of the type varchar to store either MALE or FEMALE as the value. And, the Student object has a gender property that is of the type enum as shown in the following code:

public enum Gender {
    FEMALE,
    MALE;
}

By default, MyBatis uses EnumTypeHandler to handle enum type Java properties and stores the name of the enum value. You don't need any extra configuration to do this. You can use enum type properties just like primitive type properties as shown in the following code:

public class Student {
    private Integer id;
    private String name;
    private String email;
    private PhoneNumber phone;
    private Address address;
    private Gender gender;

    //setters and getters
}

<insert id="insertStudent" parameterType="Student" useGeneratedKeys="true" keyProperty="id">
    insert into students(name,email,addr_id, phone,gender) values(#{name},#{email},#{address.addrId},#{phone},#{gender})
</insert>

When you execute the insertStudent statement, MyBatis takes the name of the Gender enum (FEMALE/MALE) and stores it in the GENDER column.

If you want to store the ordinal position of the enum instead of the enum name, you will need to explicitly configure it.

So if you want to store 0 for FEMALE and 1 for MALE in the gender column, you'll need to register EnumOrdinalTypeHandler in the mybatis-config.xml file.

<typeHandler handler="org.apache.ibatis.type.EnumOrdinalTypeHandler" javaType="com.mybatis3.domain.Gender"/>

Be careful to use ordinal values to store in the DB. Ordinal values are assigned to enum values based on their order of declaration. If you change the declaration order in Gender enum, the data in the database and ordinal values will be mismatched.