首先要引入mybatis架包
大家可以在mavenRepository中搜索
https://mvnrepository.com
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.3</version>
</dependency>
</dependencies>
然後配置鏈接數據庫的數據需要放在jdbc.properties文件中
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=UTF8&userSSL=true&serverTimezone=GMT%2B8
uName=root
password=111111
下面是mybatis的配置文件,大家可以在官網找到
<?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>
<!-- 引入jdbc的配置文件 -->
<properties resource="jdbc.properties"></properties>
<!-- 配置環境信息 -->
<environments default="development">
<environment id="development">
<!-- 事務管理器 -->
<transactionManager type="JDBC" />
<!-- 數據源 -->
<dataSource type="POOLED">
<property name="driver" value="${driverClassName}" />
<property name="url" value="${url}" />
<property name="username" value="${uName}" />
<property name="password" value="${password}" />
</dataSource>
</environment>
</environments>
<!-- 映射器 -->
<mappers>
<mapper resource="jee/pk1/UserMapper.xml" />
</mappers>
</configuration>
寫一個sql語句的接口
package jee.pk1;
public interface UserMapper {
public User get(int id);
}
再寫一個查詢語句的配置文件。注意接口和配置文件的名字要一致
<?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="jee.pk1.UserMapper">
<select id="get" resultType="jee.pk1.User" parameterType="int">
select * from users where UserId = #{id}
</select>
</mapper>
主方法:
package jee.pk1;
import java.io.IOException;
import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class App {
public static void main(String[] args) throws IOException {
String config = "mybatis-config.xml";// 代表classpath下的配置文件
InputStream is = Resources.getResourceAsStream(config);// 代表classpath下的配置文件的輸入流
// SqlSessionFactory的構建器
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
// 構建一個SqlSessionFactory
SqlSessionFactory sqlSessionFactory = builder.build(is);
// 打開一個SqlSession
SqlSession session = null;
session = sqlSessionFactory.openSession();
// userMapper是實現了UserMapper接口的一個實例
UserMapper userMapper =session.getMapper(UserMapper.class);
User user = userMapper.get(1);
System.out.println(user);
//關閉session
session.close();
//session一定會被關閉
// try(SqlSession session = sqlSessionFactory.openSession()) {
//
// // userMapper是實現了UserMapper接口的一個實例
// UserMapper userMapper = session.getMapper(UserMapper.class);
//
// User user = userMapper.get(1);
// System.out.println(user);
// }
}
}