ssm整合（spring，springmvc，mybatis），实现一对多查询

第一步：导包（由于包太多，这里就不一一介绍），整个工程目录如下：

第二步：创建两张表（本人两张表分别为users和orders），如下图所示：
users表：

orders表：

第三步：将ssm框架搭起来（spring主配置文件，mybatis主配置文件，springmvc的web.xml配置文件与xxx-servlet.xml配置文件）：
web.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SSM</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- 字符编码过滤器
	注意：必须写在所以过滤器的前面 -->
	<filter>
		<filter-name>encodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		
		<init-param>
			<param-name>encoding</param-name>
			<param-value>UTF-8</param-value>
		</init-param>
		
		<init-param>
			<param-name>forceRequestEncoding</param-name>
			<param-value>true</param-value>	
		</init-param>
		
		<init-param>
			<param-name>forceResponseEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	
	<filter-mapping>
		<filter-name>encodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
  <!-- 中央前端控制器 -->
	<servlet>
		<servlet-name>springmvc</servlet-name>
		<!-- springmvc-servlet.xml配置文件的命名 -->
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>springmvc</servlet-name>
		<!-- 与上面的servlet-name保持一致 -->
		<url-pattern>/</url-pattern>
		<!-- /:拦截所有请求 -->
	</servlet-mapping>
	
	<!-- 容器启动监听事件 -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath*:config/applicationContext.xml</param-value>
		<!-- classpath:类路径，*:所有，config:你的文件夹名，applicationContext.xml:spring主配置文件 -->
	</context-param>
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
 
</web-app>

applicationContext.xml（spring主配置文件）：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:jdbc="http://www.springframework.org/schema/jdbc"
	xmlns:jee="http://www.springframework.org/schema/jee"
	xmlns:lang="http://www.springframework.org/schema/lang"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:oxm="http://www.springframework.org/schema/oxm"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:task="http://www.springframework.org/schema/task"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
		http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
		http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-3.0.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-3.0.xsd
		http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.0.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">
<!-- spring主配置文件 -->

	<!-- 配置数据源 -->
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
		<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
		<property name="url" value="jdbc:mysql://localhost:3306/ssm"></property>
		<property name="username" value="root"></property>
		<property name="password" value="1234"></property>
	</bean>
	
	<!-- 事务管理 -->
	<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource"></property>
	</bean>
	
	<!-- 回话工厂 -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="dataSource"></property>
		<!-- 获取数据源 -->
		<property name="configLocation" value="classpath:config/config.xml"></property>
		<!-- classpath:在src目录下去找 -->
		<!-- 加载mybatis的主配置文件 -->
		<property name="mapperLocations" value="classpath*:com/zhiyuan/frank/mapper/*.xml"></property>
		<!-- classpath*:在整个项目下面去找 -->
		<!-- 自动扫描mapping.xml文件 -->
	</bean>
	
	<!-- DAO接口所在包名，Spring会自动查找其下的类 -->	
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.zhiyuan.frank.mapper"></property>
	</bean>
</beans>

config.xml（mybatis主配置文件）：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "mybatis-3-config" "mybatis-3-config.dtd" >
<configuration>
	<!-- 别名 -->
	<typeAliases>
		<package name="com.zhiyuan.frank.pojo"/>
	</typeAliases>
</configuration>

springmvc-servlet.xml（配置文件）：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

	<!-- 开启注解并扫描controller所在的指定包 -->
	<context:component-scan base-package="com.zhiyuan.frank.controller"></context:component-scan>
	
	<!-- 配置视图资源解析器 -->
	<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/pages/"></property>
		<!-- 前缀 -->
		<property name="suffix" value=".jsp"></property>
		<!-- 后缀 -->
	</bean>
</beans>

框架搭好之后可以运行一下，如果没有报错信息，则代表框架搭建成功
第四步：创建改表相对应的实体类：
推荐类与表名同名（类命名规范：类名首字母大写）
Users类：

package com.zhiyuan.frank.pojo;

import java.util.List;

public class Users {
	private int uId;
	private String username;
	private String mobile;
	private List<Orders> orders;
	public List<Orders> getOrders() {
		return orders;
	}
	public void setOrders(List<Orders> orders) {
		this.orders = orders;
	}
	public int getuId() {
		return uId;
	}
	public void setuId(int uId) {
		this.uId = uId;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getMobile() {
		return mobile;
	}
	public void setMobile(String mobile) {
		this.mobile = mobile;
	}
}

Orders类：

package com.zhiyuan.frank.pojo;

public class Orders {
	private int orderId;
	private int usersId;
	private String productName;
	private String orderNo;
	private double money;
	private Users users;
	public Users getUsers() {
		return users;
	}
	public void setUsers(Users users) {
		this.users = users;
	}
	public int getOrderId() {
		return orderId;
	}
	public void setOrderId(int orderId) {
		this.orderId = orderId;
	}
	public int getUsersId() {
		return usersId;
	}
	public void setUsersId(int usersId) {
		this.usersId = usersId;
	}
	public String getProductName() {
		return productName;
	}
	public void setProductName(String productName) {
		this.productName = productName;
	}
	public String getOrderNo() {
		return orderNo;
	}
	public void setOrderNo(String orderNo) {
		this.orderNo = orderNo;
	}
	public double getMoney() {
		return money;
	}
	public void setMoney(double money) {
		this.money = money;
	}
}

第五步：编写index.jsp页面：

<%@ page language="java" import="java.util.*"
    pageEncoding="UTF-8"%>

<%
	String basepath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath()+"/";
	//一种获取页面的方式
%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>获取页面</title>
</head>
<body>
	<h1><a href="users">获取用户所有订单</a></h1>
	<h1><%=basepath %></h1>
</body>
</html>

第六步：编写UsersController.java页面：

package com.zhiyuan.frank.controller;
/**
 * 该类指的是SpringMVC中的C，代表控制器，业务的逻辑都写在该类中
 */
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import com.zhiyuan.frank.mapper.Userslist;
import com.zhiyuan.frank.pojo.*;

@Controller
//@Controller 用于标记在一个类上，通俗来说，被Controller标记的类就是一个控制器，这个类中的方法，就是相应的动作。
@RequestMapping("/users")//users与index中a标签中href属性保持一致
//@RequestMapping是一个用来处理请求地址映射的注解，可用于类或方法上。用于类上，表示类中的所有响应请求的方法都是以该地址作为父路径。
public class UsersController {
	@Autowired
	//@Autowired注解是按照类型（byType）装配依赖对象，默认情况下它要求依赖对象必须存在，如果允许null值，可以设置它的required属性为false
	Userslist list;
	
	@RequestMapping
	public ModelAndView firstssm(){
		ModelAndView mav = new ModelAndView("order_form");//"order_form":是返回页面的名字
		//实例化一个ModelAndView对象
		Users users = list.GetUsersID(1);
		//调用接口层的方法并传入参数
		List<Orders> list = users.getOrders();
		mav.addObject("users",list);//"user":键,list:值(这里的值是接口层查询完后返回的值)
		mav.addObject("username",users.getUsername());
		//把查询结果封装到模型视图里面
		return mav;
	}
}

第七步：编写Userslist.java接口：

package com.zhiyuan.frank.mapper;

import com.zhiyuan.frank.pojo.Users;

public interface Userslist {
	public Users GetUsersID(int id);
	//这里的接口名要与mapper.xml中的select中id保持一致
}

第八步：编写usersmapper.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "mybatis-3-mapper" "mybatis-3-mapper.dtd" >
<mapper namespace="com.zhiyuan.frank.mapper.Userslist">
<!-- namespace:这里面是接口的路径 -->
	<resultMap type="users" id="MaMap">
		<result property="uId" column="u_id"/>
		<result property="username" column="username"/>
		<result property="mobile" column="mobile"/>
		<collection property="orders" ofType="orders" column="users_id">
		<!-- collection:一对多时使用，association:多对一使用 -->
			<result property="orderId" column="order_id"/>
			<result property="usersId" column="users_id"/>
			<result property="productName" column="product_name"/>
			<result property="orderNo" column="order_no"/>
			<result property="money" column="money"/>
		</collection>
	</resultMap>

	<select id="GetUsersID" parameterType="int" resultMap="MaMap">
		select * from users,orders where users.u_id = orders.users_id and users.u_id=#{id}
	</select>
</mapper>

第九步：编写order_form.jsp返回jsp页面：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!-- prefix:别名，需要用forEach得通过uri="http://java.sun.com/jsp/jstl/core"取的别名调用 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>查询结果页面</title>
</head>
<body>
	
	<table border="5" bordercolor="blue">
	<!-- border:边框宽度，bordercolor:边框颜色 -->
	<tr>
		<td colspan="3">用户名:${username }<!-- el表达式，${username }:el表达式中放的是传过来的键 --></td>
		<!-- colspan:跨列合并，rowspan:跨行合并 -->
	</tr>
	<tr>
		<td>商品名称</td>
		<td>订单号</td>
		<td>订单总额</td>
		<!-- 如果传过来的值只有一条，则不需要使用循环，${users}:el表达式中放的是传过来的键 -->
		<c:forEach items="${users}" var="orders">
		<!-- c:通过prefix取的别名，可以该为任意值，取名为c是规范，作用是调用forEach方法，
		forEach:相当于for循环，items:里面放循环对象，var:任意取名，然后通过该名调用要显示的值 -->
			<tr>
				<td>${orders.productName }<!-- el表达式 --></td>
				<td>${orders.orderNo }</td>
				<td>${orders.money }</td>
			</tr>
		</c:forEach>
	</tr>
	</table>
</body>
</html>

运行结果，如下图所示：
index.jsp页面：

order_form.jsp返回结果页面：