一、mybatis

主要属性:

1、typeHandler：不过要自定义处理类，要继承BaseTypeHandler； 数据的读写都会被这个类所过滤

<resultMap id="getTestConfigByCode" type="com.xxxxx.entity.TestConfig">
    <id column="id" jdbcType="NUMERIC" property="id"/>
    <result column="test_json" javaType="com.xxx.xxx.vo.TestJsonVO"
            typeHandler="com.xxxx.xx.config.handler.JsonTypeHandler"
            jdbcType="VARCHAR"
            property="testJson" />
</resultMap>

自定义 typeHandler 类

MappedTypes(JSONObject.class)
@MappedJdbcTypes(JdbcType.VARCHAR)
public class JsonTypeHandler<T extends Object> extends BaseTypeHandler<T> {

    private              Class<T>     clazz;

    public JsonTypeHandler(Class<T> clazz) {
        if (clazz == null) {
            throw new IllegalArgumentException("Type argument cannot be null");
        }
        this.clazz = clazz;
    }

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, T parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, JSON.toJSONString(parameter));
    }

    @Override
    public T getNullableResult(ResultSet rs, String columnName) throws SQLException {
        return this.toObject(rs.getObject(columnName), clazz);
    }

    @Override
    public T getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        return this.toObject(rs.getObject(columnIndex), clazz);
    }

    @Override
    public T getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        return this.toObject(cs.getObject(columnIndex), clazz);
    }

    private T toObject(Object content, Class<T> clazz) {
        if (content == null) {
            return null;
        }
        return JSON.parseObject(content.toString(), clazz);

    }
}

一、mybatis-plus

mybatis-plus就方便多了，框架已经实现了自定义typeHandler类

1、可以像mybatis一样在xml中配置typeHandler属性： 

typeHandler = "com.baomidou.mybatisplus.extension.handlers.jacksonTypeHandler"

2、可以在实体类中用注解：

@TableField(typeHandler = JacksonTypeHandler.class)