环境的搭建
我们使用IDEA创建一个maven项目,在pom.xml中书写以下配置文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>MyBatisDemo</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.25</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
</project>
右键重新载入项目即可实现导入
在mysql中提前建好表
<?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>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/user?useSSL=true&useUnicode=true&characterEncoding=utf8"/>
<property name="username" value="root"/>
<property name="password" value="c8918833"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/caoyuqi/mapper/UserMapper.xml"/>
</mappers>
</configuration>
书写mybatis-config.xml文件
这里要注意数据库url的书写,&代表&。在下面的mappers中书写匹配的mapper配置
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.caoyuqi.dao.UserDao">
<select id="getAllUser" resultType="com.caoyuqi.model.User">
select * from User.man;
</select>
</mapper>
在mapper中我们要书写resultType代表返回的结果类型,selectid对应Mapper相应的方法名 namespace对应相关的Dao
package com.caoyuqi.dao;
import com.caoyuqi.model.User;
import java.util.List;
public interface UserDao {
List<User> getAllUser();
}
package com.caoyuqi.utils;
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 {
String resource = "mybatis-config.xml";
InputStream inputStream = null;
try {
inputStream = Resources.getResourceAsStream(resource);
} catch (IOException e) {
e.printStackTrace();
}
sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
}
public static SqlSession getMapping()
{
SqlSession sqlSession = sqlSessionFactory.openSession();
return sqlSession;
}
}
Mybatis最重要的获取session代码如上所示
import com.caoyuqi.dao.UserDao;
import com.caoyuqi.model.User;
import com.caoyuqi.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserTest {
@Test
public void testQuery()
{
SqlSession mapping = MybatisUtils.getMapping();
UserDao mapper = mapping.getMapper(UserDao.class);
List<User> allUser = mapper.getAllUser();
for (User user :
allUser) {
System.out.println(user);
}
}
}
编写相关的测试代码
如此我们便编写了第一个Mybatis程序对数据库进行了查询操作