MyBatis3——mybatis与spring整合（传统dao方式）

1. spring与mybatis整合的配置文件

1.1 mybatis的核心配置文件

          我们将mybatis与spring整合之后，以前在核心配置文件中的内容，现在都可以交给spring来管理了，所以，该文件，我们只需要有一个空的文件即可。但是这个空的配置文件，又一定需要，否则会报错。

SqlMapConfig.xml

<?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>

</configuration>

注意：

1. 核心配置文件中也可以做别名的配置

<?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>
		<package name="com.bjc.pojo"/>
	</typeAliases>
</configuration>

2. 还可以做其他的配置 

1.2 spring的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
	http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
	http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">

	<!-- 加载配置文件 -->
	<context:property-placeholder location="classpath:jddb.properties" />

	<!-- 数据库连接池 -->
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">
		<property name="driverClassName" value="${jdbc.driver}" />
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
		<property name="maxActive" value="10" />
		<property name="maxIdle" value="5" />
	</bean>
	
	<!-- 加载mybatis核心配置文件 -->
	<bean class="org.mybatis.spring.SqlSessionFactoryBean" id="sqlSessionFactory">
		<!-- 数据源 -->
		<property name="dataSource" ref="dataSource"></property>
		<!-- 核心配置文件 -->
		<property name="configLocation" value="classpath:SqlMapConfig.xml"></property>
		<!-- 配置别名包扫描  name为typeAliasesPackage  value为pojo的包名-->
		<property name="typeAliasesPackage" value="com.bjc.pojo"></property>
	</bean>

</beans>

2. Dao层代码

原始的dao开发接口+实现类，实现类需要继承SqlSessionDaoSupport 

2.1 UserDaoImpl实现类

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {

	@Override
	public User getUserById(Integer id) {
		SqlSession sqlSession = super.getSqlSession();
		//查询用户
		User user = sqlSession.selectOne("user.getUserById", id);
		
		//不能关闭SqlSession
		//sqlSession.close();
		return user;
	}

	@Override
	public List<User> getUserByUserName(String name) {
		SqlSession sqlSession = super.getSqlSession();
		List<User> list = sqlSession.selectList("user.getUserByName", name);
		//不能关闭SqlSession
		return list;
	}

	@Override
	public void insertUser(User user) {
		SqlSession sqlSession = super.getSqlSession();
		sqlSession.insert("user.insertUser", user);
		//不用手动提交事务，交给spring
	}
}

2.2 映射文件

user.xml

<?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="user">
	
	<select id="getUserByName" parameterType="string" resultType="com.bjc.mybatis.pojo.User">
		SELECT 	id, 
			`username`, 
			birthday, 
			sex, 
			address
		FROM user 
		where `username` like '%${value}%'
	</select>

	
	<update id="updateUser" parameterType="com.bjc.mybatis.pojo.User">
		update user
		set
		username=#{username},
		address=#{address}
		where id=#{id}
	</update>
	
	<delete id="delUser" parameterType="int">
		delete from user where id=#{id}
	</delete>
</mapper>

注意：这个配置文件是简写内容。

2.3 在加载映射文件

在mybatis的核心配置文件中，通过mapper标签加载映射文件

<?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>
		<package name="com.bjc.pojo"/>
	</typeAliases>
	
	<mappers>
		<mapper resource="mybatis/user.xml"></mapper>
	</mappers>
</configuration>

2.4 在spring的配置文件中配置dao

<!-- 传统dao  -->
<bean class="com.itheima.mybatis.dao.impl.UserDaoImpl">
	<property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

2.5 测试

public class UserDaoTest {
	
	private ApplicationContext applicationContext;
	
	@Before
	public void init(){
		applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
	}

	@Test
	public void testGetUserById() {
		UserDao userDao = applicationContext.getBean(UserDao.class);
		User user = userDao.getUserById(10);
		System.out.println(user);
	}

}