To encrypt database data in MyBatis, you can use a combination of MyBatis and Java encryption libraries. Here are the general steps you can follow:

1. Choose an encryption library: There are many encryption libraries available for Java, such as Jasypt and Bouncy Castle. Choose one that fits your needs and integrate it into your project.

2. Encrypt the data: In your MyBatis mapper XML file, you can use the encryption library to encrypt the data before it is stored in the database. For example, you can use the 

   encrypt

    function provided by Jasypt:

<insert id="insertUser" parameterType="User">

INSERT INTO users (username, password)

VALUES (#{username}, encrypt(#{password}, 'myEncryptionKey'))

</insert>

In this example, the 

encrypt

 function takes two arguments: the data to be encrypted (

#{password}

) and the encryption key (

'myEncryptionKey'

). The encrypted data is then stored in the database.

1. Decrypt the data: When retrieving data from the database, you can use the encryption library to decrypt the data before returning it to the user. For example, you can use the 

   decrypt

    function provided by Jasypt:

<select id="getUser" parameterType="int" resultType="User">

SELECT id, username, decrypt(password, 'myEncryptionKey') as password

FROM users

WHERE id = #{id}

</select>

In this example, the 

decrypt

 function takes two arguments: the encrypted data (

password

) and the encryption key (

'myEncryptionKey'

). The decrypted data is then returned to the user.

Note that this is just a general approach and the specific implementation may vary depending on your requirements and the encryption library you choose to use.