数据库环境准备:
CREATE DATABASE mybatis;
USE mybatis;
CREATE TABLE `user`(
`id` INT PRIMARY KEY AUTO_INCREMENT COMMENT '主键id',
`name` VARCHAR(30) NOT NULL COMMENT '用户名',
`password` VARCHAR(30) NOT NULL COMMENT '密码'
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO USER(`name`,`password`) VALUES('Ara_Hu','123456'),('张三','123456'),('李思','123456'),('王武','123456'),('赵柳','123456'),('田七','123456'),('宋坝','123456');
编写对应的实体类:
package com.ara.pojo;
public class User {
private int id;
private String name;
private String password;
public User() {
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", password='" + password + '\'' +
'}';
}
}
回顾Mybatis操作数据库
下面展示一个简单的Mybatis的demo(这里不再对代码进行解释,如需要解释的读者,可以参考博主关于Mybatis入门的文章)
先导入Mybatis简单demo所需要的依赖:
<!-- 单元测试 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<!-- 数据库连接 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.46</version>
</dependency>
<!-- Mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.4</version>
</dependency>
编写配置文件(mybatis-config.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>
<typeAliases>
<package name="com.ara.pojo" />
</typeAliases>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSl=true&useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper class="com.ara.mapper.UserMapper" />
</mappers>
</configuration>
编写Mybatis工具类(MybatisUtils):
package com.ara.util;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
}
}
编写UserMapper接口:
package com.ara.mapper;
import com.ara.pojo.User;
import java.util.List;
public interface UserMapper {
List<User> selectUsers();
}
编写UserMapper.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="com.ara.mapper.UserMapper">
<select id="selectUsers" resultType="User">
select * from user;
</select>
</mapper>
测试代码:
@Test
public void mybatisTest(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<User> users = mapper.selectUsers();
for (User user : users) {
System.out.println(user);
}
sqlSession.close();
}
测试结果如下:
说明Mybatis环境没问题,我们现在将它和Spring进行整合。
Spring整合Mybatis
我们知道Spring就是帮助我们管理之前需要new出来的东西,所以我们就需要想办法将我们使用的Mybatis是new出来的对象交由Spring托管即可。
还是先导入需要的依赖:
<!-- 使用SpringMVC便于导入所有Spring依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<!-- Spring的JDBC -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<!-- Mybatis整合Spring的依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.4</version>
</dependency>
然后编写Spring关于dao层的配置文件(spring-dao.xml):
<?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:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--
DataSource:使用Spring的数据源替换Mybatis的配置
我们这里使用Spring提供的JDBC:org.springframework.jdbc.datasource
-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSl=true&useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</bean>
<!-- SqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 使用上面的数据源 -->
<property name="dataSource" ref="dataSource" />
<!-- 绑定Mybatis的配置文件 -->
<property name="configLocation" value="classpath:mybatis-config.xml"/>
<!-- 指定Mapper的配置文件 -->
<property name="mapperLocations" value="classpath:com/ara/mapper/*.xml"/>
</bean>
<!-- SqlSession -->
<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
<!-- 只能使用构造器注入sqlSessionFactory,因为该类没有set方法 -->
<constructor-arg index="0" ref="sqlSessionFactory"/>
</bean>
</beans>
由于我们在Spring中配置了数据源和指定了Mapper配置文件,所以我们在Mybatis配置文件中就可以将重复的去掉,留下的内容如下:
<?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.ara.pojo" />
</typeAliases>
</configuration>
接下来最重要的就是把UserMapper接口的实现类交由Spring管理,这里我们暂时先手动写一个它的实现类(UserMapperImpl):
package com.ara.mapper;
import com.ara.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;
public class UserMapperImpl implements UserMapper {
//我们所有的操作,在以前都使用sqlSession来执行,现在这里使用sqlSessionTemplate和它一致的用法
private SqlSessionTemplate sqlSession;
public void setSqlSession(SqlSessionTemplate sqlSession) {
this.sqlSession = sqlSession;
}
public List<User> selectUsers() {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.selectUsers();
}
}
然后我们将其交由Spring管理,再创建一个Spring的主配置文件(applicationContext.xml):
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 引入spring-dao.xml配置文件 -->
<import resource="spring-dao.xml"/>
<!-- 注册bean -->
<bean id="userMapper" class="com.ara.mapper.UserMapperImpl">
<property name="sqlSession" ref="sqlSession"/>
</bean>
</beans>
到此,我们就算是配置完了,就该测试了,测试代码如下:
@Test
public void mybatisSpringTest() throws IOException {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
List<User> users = userMapper.selectUsers();
for (User user : users) {
System.out.println(user);
}
}
测试结果如下:
测试成功,说明我们使用Spring整合Mybatis就成功了。
上述方式博主认为还是有点繁琐,因为我们手动创建了一个Mapper接口的实现类,感觉又回到了以前。。。所以博主这里还有另一种方式:
这种方式就可以把UserMapperImpl类删除了,而且仅需对上述配置文件进行一点更改即可:
- 更改spring-dao.xml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:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--
DataSource:使用Spring的数据源替换Mybatis的配置
我们这里使用Spring提供的JDBC:org.springframework.jdbc.datasource
-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSl=true&useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="rootroot"/>
</bean>
<!-- <!– SqlSessionFactory –>-->
<!-- <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">-->
<!-- <!– 使用上面的数据源 –>-->
<!-- <property name="dataSource" ref="dataSource" />-->
<!-- <!– 绑定Mybatis的配置文件 –>-->
<!-- <property name="configLocation" value="classpath:mybatis-config.xml"/>-->
<!-- <!– 指定Mapper的配置文件 –>-->
<!-- <property name="mapperLocations" value="classpath:com/ara/mapper/*.xml"/>-->
<!-- </bean>-->
<!-- <!– SqlSession –>-->
<!-- <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">-->
<!-- <!– 只能使用构造器注入sqlSessionFactory,因为该类没有set方法 –>-->
<!-- <constructor-arg index="0" ref="sqlSessionFactory"/>-->
<!-- </bean>-->
<!-- 配置SqlSessionFactory对象 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 注入数据库连接池 -->
<property name="dataSource" ref="dataSource"/>
<!-- 配置MyBaties全局配置文件:mybatis-config.xml -->
<property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>
<!-- 配置扫描Dao接口包,动态实现Dao接口注入到spring容器中 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 注入sqlSessionFactory -->
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<!-- 给出需要扫描Dao接口包 -->
<property name="basePackage" value="com.ara.mapper"/>
</bean>
</beans>
- 更改applicationContext.xml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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 引入spring-dao.xml配置文件 -->
<import resource="spring-dao.xml"/>
<!-- 注册bean -->
<!-- <bean id="userMapper" class="com.ara.mapper.UserMapperImpl">-->
<!-- <property name="sqlSession" ref="sqlSession"/>-->
<!-- </bean>-->
</beans>
采用这种方式,我们就可以不用再写dao层接口的实现类了。
测试代码不变,然后运行结果如下:
这也测试成功了。
在开发中,博主常用后面这种方式来整合Mybatis。