There is case that a TypeHandler is incorrectly selected for a nested select query parameter

[dezhishen]

there are two table with the same column name 'ID' and without the same type

    <resultMap id="BaseResultMap" type="com.geco.domain.MdProduct">
        <id column="ID" property="id" jdbcType="VARCHAR" />
        ...
     </resultMap>

    <resultMap id="InfoResultMap" extends="BaseResultMap"  type="com.geco.service.product.dto.ProductResp">
        <result column="INFO_ID" property="additionalInfo.id" jdbcType="DECIMAL"/>
      ....
       <collection property="skus"
                    select="selectSkuByPk1" column="ID"/>
    </resultMap>

<select id="select resultMap="InfoResultMap">

   select p.id ,i.ID as INFO_ID from md_product,md_product_info i
where ....
</select>

there are error info

org.apache.ibatis.executor.result.ResultMapException: Error attempting to get column 'ID' from result set.  Cause: java.sql.SQLException: Invalid value for getLong() - '82620ef6659811e9809900163e02c6cf'

I debug it and try fix it

class:  org.apache.ibatis.type.UnknownTypeHandler
method:  private TypeHandler<?> resolveTypeHandler(ResultSet rs, String column)

old code:

private TypeHandler<?> resolveTypeHandler(ResultSet rs, String column) {
        try {
            Map<String, Integer> columnIndexLookup = new HashMap();
            ResultSetMetaData rsmd = rs.getMetaData();
            int count = rsmd.getColumnCount();

            for (int i = 1; i <= count; ++i) {
                String name = rsmd.getColumnName(i);
                columnIndexLookup.put(name, i);
            }

            Integer columnIndex = (Integer) columnIndexLookup.get(column);
            TypeHandler<?> handler = null;
            if (columnIndex != null) {
                handler = this.resolveTypeHandler(rsmd, columnIndex);
            }

            if (handler == null || handler instanceof UnknownTypeHandler) {
                handler = OBJECT_TYPE_HANDLER;
            }

            return (TypeHandler) handler;
        } catch (SQLException var8) {
            throw new TypeException("Error determining JDBC type for column " + column + ".  Cause: " + var8, var8);
        }
    }

this is my code:

private TypeHandler<?> resolveTypeHandler(ResultSet rs, String column) {
        try {
            Map<String, Integer> columnIndexLookup = new HashMap();
            ResultSetMetaData rsmd = rs.getMetaData();
            int count = rsmd.getColumnCount();

            for (int i = 1; i <= count; ++i) {
                String name = rsmd.getColumnLabel(i);
                columnIndexLookup.put(name, i);
            }

            Integer columnIndex = (Integer) columnIndexLookup.get(column);
            TypeHandler<?> handler = null;
            if (columnIndex != null) {
                handler = this.resolveTypeHandler(rsmd, columnIndex);
            }

            if (handler == null || handler instanceof UnknownTypeHandler) {
                handler = OBJECT_TYPE_HANDLER;
            }

            return (TypeHandler) handler;
        } catch (SQLException var8) {
            throw new TypeException("Error determining JDBC type for column " + column + ".  Cause: " + var8, var8);
        }
    }

getColumnName = > getColumnLabel

it works but i don't know there are any other bugs after i fixed this bug

[harawata]

Hi @dezhishen ,

Could you provide a demo project with a minimum set of tables/columns?
Thanks in advance!

[dezhishen]

@harawata
Table

create table product
(
id varchar(32) not null,
code varchar(80) not null,
name varchar(240) not null
);
create table product_sku
(
id varchar(32) not null,
product_id varchar(32) not null,
code varchar(80) not null,
color varchar(40),
size varchar(40)
);
create table product_info
(
id int(11)  not null,
product_id varchar(32) not null,
other_info varchar(240) 
);

ProductSku.class

public class ProductSku {
    private String id;
    private String color;
    private String size;
    private String productId;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public String getSize() {
        return size;
    }

    public void setSize(String size) {
        this.size = size;
    }

    public String getProductId() {
        return productId;
    }

    public void setProductId(String productId) {
        this.productId = productId;
    }
}

ProductInfo.class

public class ProductInfo {
    private Long id;
    private String productId;
    private String otherInfo;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getProductId() {
        return productId;
    }

    public void setProductId(String productId) {
        this.productId = productId;
    }

    public String getOtherInfo() {
        return otherInfo;
    }

    public void setOtherInfo(String otherInfo) {
        this.otherInfo = otherInfo;
    }
}

ProductResp.class

public class ProductResp {
    private String id;
    private String code;
    private String name;
    private List<ProductSku> skus;
    private ProductInfo productInfo;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<ProductSku> getSkus() {
        return skus;
    }

    public void setSkus(List<ProductSku> skus) {
        this.skus = skus;
    }

    public ProductInfo getProductInfo() {
        return productInfo;
    }

    public void setProductInfo(ProductInfo productInfo) {
        this.productInfo = productInfo;
    }
}

ProductMapper.xml

<mapper namespace="ProductMapper">
   <resultMap id="AllInfoResultMap" type="ProductResp">
        <id column="ID" property="id" jdbcType="VARCHAR"/>
        <result column="NAME" property="name" jdbcType="VARCHAR"/>
        <result column="CODE" property="code" jdbcType="VARCHAR"/>
        <result column="INFO_ID" property="productInfo.id" jdbcType="DECIMAL"/>
        <result column="INFO_OTHER_INFO" property="productInfo.otherInfo" jdbcType="VARCHAR"/>
        <collection property="skus"
                    select="selectSkuByPk1" column="ID"/>
    </resultMap>
    <select id="selectAllInfo" resultMap="AllInfoResultMap">
         select p.id,
                   p.code,
                   p.name,
                   i.id as INFO_ID,
                   i.other_info as INFO_OTHER_INFO
          from product p left join product_info i
              on p.id = i.product_id
         where p.code = #{code,jdbcType=VARCHAR}
     </select>
    <resultMap id="SkuResultMap" type="ProductSku">
        <id column="ID" property="id" jdbcType="VARCHAR"/>
        <result column="PRODUCT_ID" property="productId" jdbcType="VARCHAR"/>
        <result column="COLOR" property="color" jdbcType="VARCHAR"/>
        <result column="SIZE" property="size" jdbcType="VARCHAR"/>
    </resultMap>
     <select id="selectSkuByPk1" resultMap="SkuResultMap">
          select * from product_sku
           where product_id = #{id,jdbcType=VARCHAR}
     </select>
</mapper>

ProductMapper.class

public interface ProductMapper {
    List<ProductResp> selectAllInfo(@Param("code") String code);
}  

Call function selectAllInfo

 <collection property="skus"
                    select="selectSkuByPk1" column="ID"/>

This code will use ID when there are two column that their names are ID without same type.

[harawata]

Thanks for the update, @dezhishen !
I think I understood the problem.

Actually, MyBatis should check the value of useColumnLabel setting.

• when useColumnLabel=true (default), getColumnLabel() should be used.
• when useColumnLabel=false, getColumnName() should be used.

I am not sure how to fix this cleanly yet.

[huangdx0726]

@dezhishen @harawata mysql驱动包5.1及以上会产生这个问题。按你的修改可以解决这个问题，如果怕引发其他bug可以改用5.0的驱动包试试。

[dezhishen]

@dezhishen @harawata mysql驱动包5.1及以上会产生这个问题。按你的修改可以解决这个问题，如果怕引发其他bug可以改用5.0的驱动包试试。

通过另外一种 <collection> 使用方式和sql关联,一次查出所有数据的方式,可以避免上述情况发生,也更好
http://www.mybatis.org/mybatis-3/zh/sqlmap-xml.html#Result_Maps
在resultMap中使用

<resultMap id="detailedBlogResultMap" type="Blog">
 ...
  <collection property="posts" ofType="Post">
    <id property="id" column="post_id"/>
    <result property="subject" column="post_subject"/>
     ...
  </collection>
    ...
</resultMap>

There are another way to use the tag <collection>.
We can query all columns only once call sql.
Like this:
http://www.mybatis.org/mybatis-3/sqlmap-xml.html#Result_Maps

resultMap:

<resultMap id="detailedBlogResultMap" type="Blog">
 ...
  <collection property="posts" ofType="Post">
    <id property="id" column="post_id"/>
    <result property="subject" column="post_subject"/>
     ...
  </collection>
    ...
</resultMap>

[kazuki43zoo]

@huangdx0726 @dezhishen , Please use English as much as possible.