ibatis Tips 之 复杂类型集合的属性

Result Map还可以装入代表复杂类型对象集合（List）的属性，用以表示在数据库中相互关系为多对多或一对多的数据。拥有集合属性的类作为“一”的一方，而在集合中的对象作为“多”的一方。用来装入对象集合的mapped statement和上面例子一样。唯一的不同是，让SQL Map架构装入复杂类型集合（List）的业务对象的属性必须是java.util.List或java.util.Collection类型

映射文件：

<!--complex type Collection property-->
<resultMap id="get-product-result" class="product">
			<result property="id" column="prd_id"/>
			<result property="description" column="prd_description"/>
			<result property="price" column="prd_price"/>
		</resultMap>
		<resultMap id="get-categery-complex-list" class="category">
			<result property="id" column="cat_id"/>
			<result property="description" column="cat_description"/>
			<result property="productList" column="cat_id" select="getProductListByCatId"/>
		</resultMap>
		
		<select id="getCategory-complex-list" resultMap="get-categery-complex-list" parameterClass="int">
			<![CDATA[
				select * from t_category where cat_id = #value#
			]]>
		</select>
		
		<select id="getProductListByCatId" resultMap="get-product-result" >
			<![CDATA[	
				select * from t_product where prd_cat_id=#value#
			]]>
		</select>

 DAO层：

public Category getProductUseComplexTypeList(int id) throws SQLException {
		init();
		Category category = (Category)sqlMapClient.queryForObject("getCategory-complex-list", id);
		return category;
	}

 Test类：

/**
	 * 测试复杂类型集合的属性
	 * @throws SQLException
	 */
	public void getProductUseComplexTypeList() throws SQLException {
		Category category = productDao.getProductUseComplexTypeList(1);
		System.out.println(category);
	}

 Category类：

package com.ibatis.dataobject;

import java.util.Iterator;
import java.util.List;

public class Category {

	@Override
	public String toString() {
		String temp = "Category---id:" + this.id + "\n" + "description:" + this.description;
		for (Iterator it=this.productList.iterator();it.hasNext();) {
			 Product product = (Product)it.next();
			 temp += "\n" + product.toString();
		}
		return temp;
	}
	private int id;
	private String description;
	private List productList;
	
	
	public List getProductList() {
		return productList;
	}
	public void setProductList(List productList) {
		this.productList = productList;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getDescription() {
		return description;
	}
	public void setDescription(String description) {
		this.description = description;
	}
	
	
	
}

 结果：

Category---id:1
description:sports
Product----id:1
description:basketball
price:206.99

Product----id:2
description:football
price:106.99