數據庫環境準備:
CREATE DATABASE mybatis;
USE mybatis;
CREATE TABLE `user`(
`id` INT PRIMARY KEY AUTO_INCREMENT COMMENT '主鍵id',
`name` VARCHAR(30) NOT NULL COMMENT '用戶名',
`password` VARCHAR(30) NOT NULL COMMENT '密碼'
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO USER(`name`,`password`) VALUES('Ara_Hu','123456'),('張三','123456'),('李思','123456'),('王武','123456'),('趙柳','123456'),('田七','123456'),('宋壩','123456');
編寫對應的實體類:
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 + '\'' +
'}';
}
}
回顧Mybatis操作數據庫
下面展示一個簡單的Mybatis的demo(這裏不再對代碼進行解釋,如需要解釋的讀者,可以參考博主關於Mybatis入門的文章)
先導入Mybatis簡單demo所需要的依賴:
<!-- 單元測試 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<!-- 數據庫連接 -->
<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>
編寫配置文件(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>
編寫Mybatis工具類(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();
}
}
編寫UserMapper接口:
package com.ara.mapper;
import com.ara.pojo.User;
import java.util.List;
public interface UserMapper {
List<User> selectUsers();
}
編寫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>
測試代碼:
@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();
}
測試結果如下:
說明Mybatis環境沒問題,我們現在將它和Spring進行整合。
Spring整合Mybatis
我們知道Spring就是幫助我們管理之前需要new出來的東西,所以我們就需要想辦法將我們使用的Mybatis是new出來的對象交由Spring託管即可。
還是先導入需要的依賴:
<!-- 使用SpringMVC便於導入所有Spring依賴 -->
<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的依賴 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.4</version>
</dependency>
然後編寫Spring關於dao層的配置文件(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的數據源替換Mybatis的配置
我們這裏使用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">
<!-- 使用上面的數據源 -->
<property name="dataSource" ref="dataSource" />
<!-- 綁定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">
<!-- 只能使用構造器注入sqlSessionFactory,因爲該類沒有set方法 -->
<constructor-arg index="0" ref="sqlSessionFactory"/>
</bean>
</beans>
由於我們在Spring中配置了數據源和指定了Mapper配置文件,所以我們在Mybatis配置文件中就可以將重複的去掉,留下的內容如下:
<?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>
接下來最重要的就是把UserMapper接口的實現類交由Spring管理,這裏我們暫時先手動寫一個它的實現類(UserMapperImpl):
package com.ara.mapper;
import com.ara.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;
public class UserMapperImpl implements UserMapper {
//我們所有的操作,在以前都使用sqlSession來執行,現在這裏使用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();
}
}
然後我們將其交由Spring管理,再創建一個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"/>
<!-- 註冊bean -->
<bean id="userMapper" class="com.ara.mapper.UserMapperImpl">
<property name="sqlSession" ref="sqlSession"/>
</bean>
</beans>
到此,我們就算是配置完了,就該測試了,測試代碼如下:
@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);
}
}
測試結果如下:
測試成功,說明我們使用Spring整合Mybatis就成功了。
上述方式博主認爲還是有點繁瑣,因爲我們手動創建了一個Mapper接口的實現類,感覺又回到了以前。。。所以博主這裏還有另一種方式:
這種方式就可以把UserMapperImpl類刪除了,而且僅需對上述配置文件進行一點更改即可:
- 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的數據源替換Mybatis的配置
我們這裏使用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">-->
<!-- <!– 使用上面的數據源 –>-->
<!-- <property name="dataSource" ref="dataSource" />-->
<!-- <!– 綁定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">-->
<!-- <!– 只能使用構造器注入sqlSessionFactory,因爲該類沒有set方法 –>-->
<!-- <constructor-arg index="0" ref="sqlSessionFactory"/>-->
<!-- </bean>-->
<!-- 配置SqlSessionFactory對象 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 注入數據庫連接池 -->
<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>
<!-- 配置掃描Dao接口包,動態實現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"/>
<!-- 給出需要掃描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"/>
<!-- 註冊bean -->
<!-- <bean id="userMapper" class="com.ara.mapper.UserMapperImpl">-->
<!-- <property name="sqlSession" ref="sqlSession"/>-->
<!-- </bean>-->
</beans>
採用這種方式,我們就可以不用再寫dao層接口的實現類了。
測試代碼不變,然後運行結果如下:
這也測試成功了。
在開發中,博主常用後面這種方式來整合Mybatis。