因最近会用到mybatis相关,好久木有用了, 赶紧来回顾以及记录并分享下:
这一章先来分享一下单表查询是如何实现的:
一、添加mybatis依赖
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>x.x.x</version>
</dependency>
二、添加xml数据库配置文件
<?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>
<environments default="development">
<environment id="development">
<!-- 配置事务-->
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<!-- 配置驱动-->
<property name="driver" value="${driver}"/>
<!-- 配置数据库地址-->
<property name="url" value="${url}"/>
<!-- 配置数据库用户名-->
<property name="username" value="${username}"/>
<!-- 配置数据库密码-->
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<!-- 配置实体类对应xml文件-->
<mapper resource="org/mybatis/example/BlogMapper.xml"/>
</mappers>
</configuration>
三、读取xml文件创建SqlSessionFactory对象
//配置文件路径
String resource = "org/mybatis/example/mybatis-config.xml";
//获取配置文件
InputStream inputStream = Resources.getResourceAsStream(resource);
//通过配置文件获取SqlSessionFactory对象
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
四、创建sql语句以及创建SqlSession对象
1)配置sql查询语句
<?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="org.mybatis.example.BlogMapper">
<!-- 以id为参数查询结果-->
<select id="selectBlog" resultType="Blog">
select * from Blog where id = #{id}
</select>
</mapper>
2)创建SqlSession对象
try (SqlSession session = sqlSessionFactory.openSession()) {
Blog blog = session.selectOne(
"org.mybatis.example.BlogMapper.selectBlog", 101);
}