import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.springframework.stereotype.Component;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
/**
 * @ClassName ListToStringHandler
 * @Description mybatis list轉(zhuǎn)換為String 相互轉(zhuǎn)換工具類
 * @Author ygt
 * @Date 2021/3/3 14:49
 * @Version V1.0
 */
@Component
public class ListToStringHandler  extends BaseTypeHandler<List> {
    @Override
    public void setNonNullParameter(PreparedStatement preparedStatement, int i, List list, JdbcType jdbcType) throws SQLException {
        preparedStatement.setString(i, JSON.toJSONString(list));
    }
    @Override
    public List getNullableResult(ResultSet resultSet, String s) throws SQLException {
        JSONArray jsonArray = JSONArray.parseArray( resultSet.getString(s));
        return jsonArray;
    }
    @Override
    public List getNullableResult(ResultSet resultSet, int i) throws SQLException {
        JSONArray jsonArray = JSONArray.parseArray( resultSet.getString(i));
        return jsonArray;
    }
    @Override
    public List getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
        JSONArray jsonArray = JSONArray.parseArray( callableStatement.getString(i));
        return jsonArray;
    }
}

<resultMap id="BaseResultMap" type="xxxx.GameMatch">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="game_id" jdbcType="INTEGER" property="gameId" />
    <result column="positions" jdbcType="VARCHAR"  property="positions" typeHandler="xxx.util.ListToStringHandler" />
    <result column="sub_channels" jdbcType="VARCHAR"  property="subChannels" typeHandler="xxx.util.ListToStringHandler" />
  </resultMap>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from game_match
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="xxx.model.GameMatch">
    insert into game_match (id, game_id, positions, 
      sub_channels)
    values (#{id,jdbcType=INTEGER}, #{gameId,jdbcType=INTEGER}, #{positions, jdbcType=VARCHAR ,typeHandler=xxx.util.ListToStringHandler},
      #{subChannels,jdbcType=VARCHAR})
  </insert>
  <update id="updateByPrimaryKey" parameterType="xxx.model.GameMatch">
    update game_match
    set game_id = #{gameId,jdbcType=INTEGER},
      positions = #{positions, jdbcType=VARCHAR ,typeHandler=xxx.util.ListToStringHandler},
      sub_channels = #{subChannels, jdbcType=VARCHAR ,typeHandler=xxx.util.ListToStringHandler}
    where id = #{id,jdbcType=INTEGER}
  </update>

@MappedJdbcTypes(JdbcType.VARCHAR) //映射的jdbctype類型
@MappedTypes(List.class)   // 要轉(zhuǎn)換的數(shù)據(jù)類型
public class List2StringTypeHandler  implements TypeHandler<List<String>> {
//    實(shí)現(xiàn)TypeHandler<要轉(zhuǎn)換的java數(shù)據(jù)類型
    /**
     * 將字段處理到數(shù)據(jù)庫(kù)中
     * @param ps  prestatement
     * @param i   prestatement 設(shè)置參數(shù) 對(duì)應(yīng)的索引
     * @param parameter 要轉(zhuǎn)換的數(shù)據(jù)。。 這個(gè)類型和泛型類型一致
     * @param jdbcType
     * @throws SQLException
     */
    @Override
    public void setParameter(PreparedStatement ps, int i, List<String> parameter, JdbcType jdbcType) throws SQLException {
//        手動(dòng)將 list 處理為 string
        StringBuilder sb = new StringBuilder();
        for (String s : parameter) {
            sb.append(s).append(".");
        }
        ps.setString(i,sb.toString());
    }
    /**
     * 將resultSet 轉(zhuǎn)換為 對(duì)象對(duì)應(yīng)的字段類型
     * @param rs
     * @param columnName
     * @return
     * @throws SQLException
     */
    @Override
    public List<String> getResult(ResultSet rs, String columnName) throws SQLException {
//        將字符串 轉(zhuǎn)換為 list
        String s = rs.getString(columnName);
        String[] arr = s.split(",");
        return Arrays.asList(arr);
    }
    @Override
    public List<String> getResult(ResultSet rs, int columnIndex) throws SQLException {
        return null;
    }
	// 存儲(chǔ)過(guò)程用到
    @Override
    public List<String> getResult(CallableStatement cs, int columnIndex) throws SQLException {
        return null;
    }
}

<configuration>
<properties resource="db.properties"></properties>
<!--    注冊(cè)typeHandler-->
    <typeHandlers>
        <package name="com.cj.typehandler"/>
    </typeHandlers>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="jdbc:mysql:///test01?serverTimezone=Asia/Shanghai"/>
                <property name="username" value="root"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--        用斜杠-->
<!--        <mapper resource="com/cj/mapper/UserMapper.xml"/>-->
        <mapper resource="com/cj/UserMapper.xml"/>
<!--        <package name="com.cj"/>-->
        <mapper resource="com/cj/TypeHandlerTransfer.xml" />
    </mappers>
</configuration>

<resultMap id="TypeHandlerMap" ?type="com.cj.TypeHandlerModel">
? ? ? ?<id property="id" column="id"/>
? ? ? ?<result property="hobby" column="hobby" ?typeHandler="com.cj.typehandler.List2StringTypeHandler"/>
? ?</resultMap>
? ?<select ?id="getEntity" ?resultMap="TypeHandlerMap">
? ? ? ?select * from typehandler
? ?</select>

?<insert id="insertEntity" >
? ? ? ?insert into typeHandler (hobby) values (#{hobby,typeHandler=com.cj.typehandler.List2StringTypeHandler})
? ? </insert>

# 設(shè)置typehandler包位置
mybatis.type-handlers-package=com.cj.typeHandler