请教一下Ibatis3/Mybatis该怎么进行一对一联合查询且不出现N+1有关问题

CREATE TABLE `t_customers` (  `customer_id` int(32) NOT NULL auto_increment,  `customer_name` varchar(50) default NULL,  `customer_address` varchar(200) default NULL,  PRIMARY KEY  (`customer_id`))CREATE TABLE `t_orders` (  `ORDER_ID` int(32) NOT NULL auto_increment,  `ORDER_NUMBER` varchar(32) default NULL,  `ORDER_DATE` date default NULL,  `ORDER_TOTAL` double(10,2) default NULL,  `PAYMENT_STATE` int(1) default NULL,  `SEND_STATE` int(1) default NULL,  `ORDER_CUSTOMER_ID` int(32) default NULL,  PRIMARY KEY  (`ORDER_ID`),  KEY `fk_orders_customers` (`ORDER_CUSTOMER_ID`),  CONSTRAINT `fk_orders_customers` FOREIGN KEY (`ORDER_CUSTOMER_ID`) REFERENCES `t_customers` (`customer_id`)-- 每一个Order(订单)对应一个Customer(客户)，t_customer的主键是t_orders的一个外键) 

package com.yuwen.domain;import java.math.BigDecimal;import java.util.Date;public class Order {        private long orderId;        private String orderNumber;        private Date orderDate;        private BigDecimal orderTotal;        private int paymentState;        private int sendState;        private Customer customer;    public Customer getCustomer() {        return customer;    }    public void setCustomer(Customer customer) {        this.customer = customer;    }    public long getOrderId() {        return orderId;    }    public void setOrderId(long orderId) {        this.orderId = orderId;    }    public String getOrderNumber() {        return orderNumber;    }    public void setOrderNumber(String orderNumber) {        this.orderNumber = orderNumber;    }    public Date getOrderDate() {        return orderDate;    }    public void setOrderDate(Date orderDate) {        this.orderDate = orderDate;    }        public BigDecimal getOrderTotal() {        return orderTotal;    }    public void setOrderTotal(BigDecimal orderTotal) {        this.orderTotal = orderTotal;    }    public int getPaymentState() {        return paymentState;    }    public void setPaymentState(int paymentState) {        this.paymentState = paymentState;    }    public int getSendState() {        return sendState;    }    public void setSendState(int sendState) {        this.sendState = sendState;    }    }

package com.yuwen.domain;public class Customer {    private long customerId;        private String customerName;        private String customerAddress;        public long getCustomerId() {        return customerId;    }    public void setCustomerId(long customerId) {        this.customerId = customerId;    }    public String getCustomerName() {        return customerName;    }    public void setCustomerName(String customerName) {        this.customerName = customerName;    }    public String getCustomerAddress() {        return customerAddress;    }    public void setCustomerAddress(String customerAddress) {        this.customerAddress = customerAddress;    }    }

<?xml version="1.0" encoding="UTF-8"?>    <!DOCTYPE configuration PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN"   "http://ibatis.apache.org/dtd/ibatis-3-config.dtd">    <configuration>        <properties resource="properties/config.properties"/>      <settings>          <setting name="lazyLoadingEnabled" value="true"/>            </settings>      <typeAliases>          <typeAlias type="com.yuwen.domain.Order" alias="order" />          <typeAlias type="com.yuwen.domain.Customer" alias="customer"/>    </typeAliases>      <environments default="development">          <environment id="development">              <transactionManager type="JDBC"/>              <dataSource type="POOLED">                <property name="driver" value="${driver}" />                  <property name="url" value="${url}" />                  <property name="username" value="${username}" />                  <property name="password" value="${password}" />              </dataSource>          </environment>      </environments>      <mappers>          <mapper resource="com/yuwen/domain/Order.xml" />    </mappers>         </configuration>