What is the custom method for mybatis typehandler?

MyBatis TypeHandler is a tool used for converting between database types and Java types, allowing for customization of conversion logic through custom methods.

To create a custom TypeHandler, you need to implement the org.apache.ibatis.type.TypeHandler interface and override its methods. Some commonly used methods in the TypeHandler interface are as follows:

1. setParameter(PreparedStatement ps, int i, T parameter, JdbcType jdbcType)：Sets a Java type parameter into a PreparedStatement object for use when executing SQL statements.
2. getResult(ResultSet rs, String columnName): Retrieve the value of the specified column name from the ResultSet object, convert it to the Java type, and return the result.
3. getResult(ResultSet rs, int columnIndex): Retrieve and convert the value from the specified column index in the ResultSet object to a Java type, and return the result.
4. Retrieve the value from the specified column index in the CallableStatement object, convert it to a Java type, and return the result.
5. javaType() returns the Java type handled by the TypeHandler.
6. jdbcType(): returns the database type handled by the TypeHandler.
7. In the setParameter method, this method will be called only when the parameter is not null, and it is used to set a non-null value to the PreparedStatement object.

By rewriting these methods, custom type conversion logic can be implemented to handle specific requirements accordingly.