【Ibatis】（十一）、java.util.Map作为parameterClass和resultClass

1.Map作为parameterClass

映射文件：

 <!--useMaptypeasparameterClass-->
 <selectid="getProduct-Map"parameterClass="java.util.Map"resultMap="get-product-result">
 <![CDATA[
 select*fromt_product
 whereprd_id=#id#andprd_description=#description#
 ]]>
 </select>

DAO层：

 /**
 *java.util.Map作为parameterClass
 */
 publicProductgetProductMap(Mapmap)throwsSQLException{
 init();
 Productproduct=(Product)sqlMapClient.queryForObject("getProduct-Map",map);
 returnproduct;
 }

Test类：

 publicvoidgetProductMap()throwsSQLException{
 Mapmap=newHashMap();
 map.put("id",newInteger(1));
 map.put("description","basketball");
 Productproduct=productDao.getProductMap(map);
 System.out.println(product);
 }

结果：

id:1
description:basketball
price206.99

2.Map作为resultClass

映射文件：

 <resultMapid="get-product-map"class="java.util.HashMap">
 <resultproperty="id"column="prd_id"/>
 <resultproperty="description"column="prd_description"/>
 <resultproperty="price"column="prd_price"/>
 </resultMap>

 <!--STARTuseMaptypeasresultClass,MUSTusejava.util.HashMapinsteadjava.util.Map-->
 <selectid="getProdcut-MapResult"resultClass="<spanstyle="color:#ff0000;">java.util.HashMap</span>
 ">
 <![CDATA[
 select*fromt_product
 ]]>
 </select>

 <selectid="getProductUseMap-resultMap"resultMap="get-product-map">
 <![CDATA[
 select*fromt_product
 ]]>
 </select>
 <!--END-->

DAO层：

 /**
 *java.util.Map作为resultClass
 */
 publicListgetProductMapResult()throwsSQLException{
 init();
 Listlist=sqlMapClient.queryForList("getProdcut-MapResult");
 returnlist;

 }


 publicListgetProductUseMapByResultMap()throwsSQLException{
 init();
 Listlist=sqlMapClient.queryForList("getProductUseMap-resultMap");
 returnlist;
 }

Test类：

 publicvoidgetProductMapResult()throwsSQLException{
 Mapmap=null;
 Listlist=productDao.getProductMapResult();
 for(Iteratorit=list.iterator();it.hasNext();){
 //List里存放的是java.util.Map类型
 Objectobj=(Object)it.next();
 System.out.println(obj.getClass());
 System.out.println(obj);
 }
 }

 publicvoidgetProductUseMapByResultMap()throwsSQLException{
 Mapmap=null;
 Listlist=productDao.getProductUseMapByResultMap();
 for(Iteratorit=list.iterator();it.hasNext();){
 //List里存放的是java.util.Map类型
 Objectobj=(Object)it.next();
 System.out.println(obj.getClass());
 System.out.println(obj);
 }
 }

结果：

class java.util.HashMap
{prd_id=1, prd_price=206.99, prd_description=basketball}
class java.util.HashMap
{prd_id=2, prd_price=106.99, prd_description=football}
class java.util.HashMap
{price=206.99, description=basketball, id=1}
class java.util.HashMap
{price=106.99, description=football, id=2}

注意：Map作为resultClass时，必须指定具体的实现类，比如java.util.HashMap,否则会报错

Caused by: java.lang.RuntimeException: JavaBeansDataExchange could not instantiate result class. Cause: java.lang.InstantiationException: java.util.Map