ibatis 之 java.util.Map作为parameterClass和resultClass
1.Map作为parameterClass
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???映射文件：
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<!--use Map type as parameterClass--> <select id="getProduct-Map" parameterresultMap="get-product-result"> <![CDATA[ select * from t_product where prd_id=#id# and prd_description=#description# ]]> </select>
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???DAO层：
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/** * java.util.Map作为parameterClass */ public Product getProductMap(Map map) throws SQLException { init(); Product product = (Product)sqlMapClient.queryForObject("getProduct-Map", map); return product; } ?
? Test类：
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public void getProductMap() throws SQLException{ Map map = new HashMap(); map.put("id", new Integer(1)); map.put("description", "basketball"); Product product = productDao.getProductMap(map); System.out.println(product); } ?
??结果：
? id:1
? description:basketball
??price206.99
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2.Map作为resultClass
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???映射文件：
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<resultMap id="get-product-map" column="prd_id"/> <result property="description" column="prd_description"/> <result property="price" column="prd_price"/> </resultMap> <!--START use Map type as resultClass,MUST use java.util.HashMap instead java.util.Map--> <select id="getProdcut-MapResult" resultresultMap="get-product-map"> <![CDATA[ select * from t_product ]]> </select>
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??DAO层：
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/** * java.util.Map作为resultClass */ public List getProductMapResult() throws SQLException { init(); List list = sqlMapClient.queryForList("getProdcut-MapResult"); return list; } public List getProductUseMapByResultMap() throws SQLException { init(); List list = sqlMapClient.queryForList("getProductUseMap-resultMap"); return list; }?
??Test类：
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public void getProductMapResult() throws SQLException{ Map map = null; List list = productDao.getProductMapResult(); for(Iterator it=list.iterator(); it.hasNext();) { //List里存放的是java.util.Map类型 Object obj = (Object)it.next(); System.out.println(obj.getClass()); System.out.println(obj); }}public void getProductUseMapByResultMap() throws SQLException { Map map = null; List list = productDao.getProductUseMapByResultMap(); for(Iterator it=list.iterator(); it.hasNext();) { //List里存放的是java.util.Map类型 Object obj = (Object)it.next(); System.out.println(obj.getClass()); System.out.println(obj); }} ?
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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}
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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
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