MyBatis-动态SQL、关联映射、MyBatis整合Spring输入输出映射动态SQL关联映射MyBatis整合SpringMyBatis逆向工程

public class UserVo {
	// 包含其他的POJO
	private User user;
	public User getUser() {
		return user;
	}
	public void setUser(User user) {
		this.user = user;
	}
}

	<!-- 使用包装类型查询 -->
	<select id="findUserByUsername" parameterType="cn.demo.pojo.vo.UserVo" resultType="cn.demo.pojo.User">
	 	select * from user where username like 
	 	"%"#{user.username}"%"
	</select>

	/**
	 * 根据用户名查询id
	 */
	public List<User> findUserByUsername(UserVo uservo);

	<!-- 查询用户总记录数 -->
	<select id="findUserCount" resultType="Integer">
		select count(*) from user
	</select>

	<!-- 查询所有 -->
	<select id="findAllOrders" resultMap="ordersMap">
		select id,user_id,number,createtime,note from orders
	</select>

	<resultMap type="orders" id="ordersMap">		 <!-- 最终映射成POJO -->
		<id property="id" column="id"/>			 <!-- 主键映射 -->
		<result property="userId" column="user_id"/> 	 <!-- 外键映射 -->
		<result property="number" column="number"/>
		<result property="createtime" column="createtime"/>
		<result property="note" column="note"/>
	</resultMap>

	<!-- 声明sql片段 -->
	<sql id="userFields">
		id,username,sex,address
	</sql>
	<!-- 额外的字段抽取出来 -->
	<sql id="userBirthday">	
		birthday
	</sql>
	<!-- 根据条件查询用户 -->
	<select id="findUserByWhere" parameterType="user" resultType="user">
	
		select <include refid="userFields"/>,<include refid="userBirthday"/> from user 
		
		<where>  	<!-- where标签可以自动添加where，同时处理sql语句中第一个and关键字 -->
			<if test=" sex != null and sex != '' ">
				and sex = #{sex} 
			</if>
			<if test=" username != null and username != '' ">
				and username like "%"#{username}"%"
			</if>
		</where>
	</select>

	<!-- 根据多个id查询用户 -->
	<select id="findUserByIds" parameterType="uservo" resultType="User">
		select * from user
		<where>
			<!-- foreach标签：遍历
				parameterType为数组 'Integer[]'时	：collection="array"
				parameterType为集合 'list'时		：collection="list"
				parameterType为对象				：collection="对象中属性名",此时的parameterType即对象
				item： 指遍历到的元素的别名
			 -->
			<foreach collection="ids" item="id" open=" id in (" close=")" separator=",">
				#{id}
			</foreach>
		</where>
	</select>

public class OrderUser extends Orders {
	private String username;
	private String address;

	<!-- 查询所有订单，关联查询下单用户 
		一对一关联：方式1 resultType
	-->
	<select id="findOrderUser" resultType="orderuser">
		SELECT
			o.id,
			o.user_id as userId,
			o.number,
			o.createtime,
			o.note,
			u.username,
			u.address
		FROM
			orders o
		LEFT JOIN USER u ON o.user_id = u.id
	</select>

	private User user;

	<resultMap type="Orders" id="order_user_map">
		<id property="id" column="id"/>
		<result property="userId" column="user_id"/> 
		<result property="number" column="number"/>
		<result property="createtime" column="createtime"/>
		<result property="note" column="note"/>
		<!-- 一对一 -->
		<association property="user" javaType="user">
			<!-- 配置主键  表示user_id是关联查询对象的唯一标识 -->
			<id property="id" column="user_id"/> 
			<result property="username" column="username"/>
			<result property="address" column="address"/>
		</association>
	</resultMap>
	<!-- 一对一关联：方式2 resultMap -->
	<select id="findOrderUser" resultMap="order_user_map">
		SELECT
			o.id,
			o.user_id,
			o.number,
			o.createtime,
			o.note,
			u.username,
			u.address
		FROM
			orders o
		LEFT JOIN USER u ON o.user_id = u.id
	</select>

	private List<Orders> orders;

	<resultMap type="user" id="user_orders_map">
		<id property="id" column="id"/>
		<result property="username" column="username"/>
		<result property="sex" column="sex"/>
		<result property="birthday" column="birthday"/>
		<result property="address" column="address"/>
		<!-- 一对多 -->
		<collection property="orders" javaType="list" ofType="orders">
			<!-- 配置主键 -->
			<id property="id" column="oid"/>
			<result property="number" column="number"/>
			<result property="createtime" column="createtime"/>
			<result property="note" column="note"/>
		</collection>
	</resultMap>
	<!-- 查询所有用户，关联查询用户下订单信息 -->
	<select id="findUserOrders" resultMap="user_orders_map">
		SELECT
			u.id,
			u.username,
			u.sex,
			u.birthday,
			u.address,
			o.id oid,
			o.number,
			o.createtime,
			o.note
		FROM
			USER u
		LEFT JOIN orders o ON u.id = o.user_id
	</select>

	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<!-- MyBatis核心配置 -->
		<property name="configLocation" value="classpath:SqlMapConfig.xml" />
		<!-- 数据源 -->
		<property name="dataSource" ref="dataSource" />
	</bean>
	
	<!-- 原始Dao开发 -->
	<bean id="userDao" class="cn.test.mybatis.dao.impl.UserDao">
		<!-- 将sqlSessionFactory注入 -->
		<property name="sqlSessionFactory" ref="sqlSessionFactory" />
	</bean>

	@Test
	public void testFindUserByUsername() {
		ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
		IUserDao userDao = (IUserDao) ac.getBean("userDao");
		List<User> list = userDao.findUserByUsername("张");
		for (User user : list) {
			System.err.println(user);
		}
	}

	<!-- 方式1：配置Mapper代理 -->
	<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
		<!-- 配置Mapper接口 -->
		<property name="mapperInterface" value="cn.test.mybatis.Mapper.UserMapper" />
		<property name="sqlSessionFactory" ref="sqlSessionFactory" />
	</bean>

	<!-- 方式2：扫描包形式配置Mapper
		扫描包及子包接口和映射文件，此时每个mapper对象代理的id为类名，首字母小写
		前提条件：Mapper接口类和Mapper映射文件同包同名
	-->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<!-- 配置接口所在包 -->
		<property name="basePackage" value="cn.test.mybatis.Mapper" />
	</bean>

MyBatis逆向工程