Mybaits中Association元素使用

一、适用场景

Association元素适用于处理一对一类型关系，如下结构 OrderFlow和custInfo是一对一的，OrderFlow和OrderFlowInvoice也是一对一的

这种一对一的关系可以在一个表中也可以在多个表中

例子中的OrderFlow和custInfo在一个表中，OrderFlow和OrderFlowInvoice在两个表中

1、OrderFlow表的SQL如下：

CREATE TABLE `ck_order_flow_basic_info` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '自增主键',
`order_id` bigint(20) NOT NULL COMMENT '包裹级别的订单号',
`cart_id` bigint(20) DEFAULT NULL COMMENT '购物车ID',
`cust_id` bigint(20) DEFAULT NULL COMMENT '用户ID',
PRIMARY KEY (`id`),
UNIQUE KEY `order_id_inex` (`order_id`),
) ENGINE=InnoDB AUTO_INCREMENT=223 DEFAULT CHARSET=utf8 COMMENT='订单基本信息表';

2、OrderFlowInvoice表的SQL如下：

CREATE TABLE `ck_order_flow_invoice` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '自增主键',
`order_id` bigint(20) NOT NULL COMMENT '订单号',
`invoice_title` varchar(100) DEFAULT NULL COMMENT '发票抬头',
`invoice_content` varchar(50) DEFAULT NULL COMMENT '发票内容',
PRIMARY KEY (`id`),
KEY `order_id_index` (`order_id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=93 DEFAULT CHARSET=utf8 COMMENT='订单发票';

3、OrderFlow对象的Java代码：

public class OrderFlow {

private Long Id;
private Long orderId;
CustInfo custInfo;
OrderFlowInvoice invoice;

public Long getId() {
return Id;
}

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

public CustInfo getCustInfo() {
return custInfo;
}

public void setCustInfo(CustInfo custInfo) {
this.custInfo = custInfo;
}

public Long getOrderId() {
return orderId;
}

public void setOrderId(Long orderId) {
this.orderId = orderId;
}

public OrderFlowInvoice getInvoice() {
return invoice;
}

public void setInvoice(OrderFlowInvoice invoice) {
this.invoice = invoice;
}

}

4、CustInfo对象的Java代码：

public class CustInfo {
private Long cartId;

private Long custId;

public Long getCartId() {
return cartId;
}

public void setCartId(Long cartId) {
this.cartId = cartId;
}

public Long getCustId() {
return custId;
}

public void setCustId(Long custId) {
this.custId = custId;
}
}

5、OrderFlowInvoice对象的Java代码：

import java.util.Date;

public class OrderFlowInvoice {
public OrderFlowInvoice() {

}

public OrderFlowInvoice(Integer id, Long orderid) {
System.out.println(orderid);
}

private Long id;

private Long orderId;

private Short invoiceCategory;

private String invoiceTitle;

private String invoiceContent;

private Date creationDate;

private Date lastChangedDate;

public Long getId() {
return id;
}

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

public Long getOrderId() {
return orderId;
}

public void setOrderId(Long orderId) {
this.orderId = orderId;
}

public String getInvoiceTitle() {
return invoiceTitle;
}

public void setInvoiceTitle(String invoiceTitle) {
this.invoiceTitle = invoiceTitle == null ? null : invoiceTitle.trim();
}

public String getInvoiceContent() {
return invoiceContent;
}

public void setInvoiceContent(String invoiceContent) {
this.invoiceContent = invoiceContent == null ? null : invoiceContent
.trim();
}

public Date getCreationDate() {
return creationDate;
}

public void setCreationDate(Date creationDate) {
this.creationDate = creationDate;
}

public Date getLastChangedDate() {
return lastChangedDate;
}

public void setLastChangedDate(Date lastChangedDate) {
this.lastChangedDate = lastChangedDate;
}
}

二、XML配置

1、MapperXML配置

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
<typeAlias alias="OrderFlow" type="webMyBatisModel.OrderFlow"/>
</typeAliases>

<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://10.255.254.22:3306/CK0" />
<property name="username" value="writeuser"/>
<property name="password" value="ddbackend"/>
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="OrderFlow.xml"/>
</mappers>
</configuration>

2、SQL映射XML文件

<association property="custInfo" resultMap="CustResultMap"></association>是

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="webMyBatisModel.OrderFlowMapper">
<resultMap id="BaseResultMap" type="webMyBatisModel.OrderFlow">
<id column="id" property="Id" jdbcType="BIGINT" />
<result column="order_id" property="orderId" jdbcType="BIGINT" />
<association property="custInfo" resultMap="CustResultMap">
</association>
<association property="invoice" resultMap="InvoiceResultMap">
</association>
</resultMap>
<resultMap id="CustResultMap" type="webMyBatisModel.CustInfo">
<result column="cart_id" property="cartId" jdbcType="BIGINT" />
<result column="cust_id" property="custId" jdbcType="INTEGER" />
</resultMap>
<resultMap id="InvoiceResultMap" type="webMyBatisModel.OrderFlowInvoice">
<id column="id" property="id" jdbcType="BIGINT" />
<result column="order_id" property="orderId" jdbcType="BIGINT" />
<result column="invoice_category" property="invoiceCategory"
jdbcType="SMALLINT" />
<result column="invoice_title" property="invoiceTitle"
jdbcType="VARCHAR" />
<result column="invoice_content" property="invoiceContent"
jdbcType="VARCHAR" />
</resultMap>
<sql id="Base_Column_List">
id, order_id,cart_id, cust_id
</sql>

<select id="selectByPrimaryKey" resultMap="BaseResultMap"
parameterType="java.lang.Long">
select
<include refid="Base_Column_List" />
from ck_order_flow_basic_info
where id = #{id,jdbcType=BIGINT}
</select>
<select id="selectByID" resultMap="BaseResultMap" parameterType="java.lang.Long">
select
<include refid="Base_Column_List" />
from ck_order_flow_basic_info
where id = #{orderFlowId,jdbcType=BIGINT}
</select>
<select id="selectOrderByOrderID" resultMap="BaseResultMap"
parameterType="java.lang.Long">
select
<include refid="Base_Column_List" />
from ck_order_flow_basic_info
where order_id = #{orderId,jdbcType=BIGINT}
</select>
<select id="selectOrderAndInvoiceByOrderID" resultMap="BaseResultMap"
parameterType="java.lang.Long">
select o.order_id,o.id,o.cart_id,o.cust_id,v.order_id,v.invoice_category,
v.invoice_title,v.invoice_content
from ck_order_flow_basic_info as o join ck_order_flow_invoice as v
on o.order_id=v.order_id
and o.order_id = #{orderId,jdbcType=BIGINT}
</select>

三、mapper接口

import java.util.List;

public interface OrderFlowMapper {
public List<OrderFlow> selectOrderByOrderID(long orderId);
public OrderFlow selectByPrimaryKey(long id);
public OrderFlow selectByID(long id);
public OrderFlow selectOrderAndInvoiceByOrderID(long id);
}

四、测试代码

import java.io.Reader;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class Test {
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;

static {
try {
reader = Resources.getResourceAsReader("Configuration.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

// sqlSessionFactory.getConfiguration().addMapper(OrderFlowInvoiceMapper.class<OrderFlowInvoice>);
} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) {
SqlSession session = sqlSessionFactory.openSession();
try {
List<OrderFlow> orders = session
.selectList(
"webMyBatisModel.OrderFlowMapper.selectOrderAndInvoiceByOrderID",
1410677970L);
for (OrderFlow Flow : orders) {
System.out.println(Flow.getCustInfo().getCustId());
System.out.println(Flow.getInvoice().getInvoiceContent());
}

} finally {
session.close();
}
}
}