（转）ibatis Tips 之 java.util.Map作为parameterClass跟resultClass

（转）ibatis Tips 之 java.util.Map作为parameterClass和resultClass

<!--use Map type as parameterClass--><select id="getProduct-Map" parameterresultMap="get-product-result"><![CDATA[select * from t_productwhere prd_id=#id# and prd_description=#description#]]></select>

?DAO层：

/** * 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：

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

映射文件：

<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><!-- END -->

?DAO层：

/** * 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：

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);}}?

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

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转自：http://xulongfa.iteye.com/blog/429616

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