- mybatis入门介绍
/**
* 1. 接口式编程
* 原生: Dao =====> DaoImpl
* mybatis : Mapper =====> xxxMapper
* 2. SqlSession 代表数据库的一次会话, 用完需要关闭会话
* 3. SqlSession 和 Connection 一样都是线程不安全的, 所以不能放在堆区(类成员对象), 所以每次创建都应该是新的对象
* 4. mapper接口没有实现类, 但是mybatis会为其创建代理对象
* 将接口和xml进行绑定
* EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
*
*/
public class MybatisTest {
/**
* 旧方式
*/
@Test
public void test() {
SqlSession sqlSession = null;
String resource = "SqlMapConfig.xml";
try (
InputStream inputStream = Resources.getResourceAsStream(resource);
) {
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
sqlSession = sqlSessionFactory.openSession();
Employee employee = sqlSession.selectOne("com.zhazha.mybatis.bean.Employee.selectBlog", 1);
System.out.println(employee);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (null != sqlSession) {
sqlSession.close();
}
}
}
/**
* 新方式
* @throws IOException
*/
@Test
public void test1() throws IOException {
InputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = factory.openSession();
EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
Employee employee = mapper.get(1);
System.out.println(employee);
sqlSession.close();
}
}
旧方式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.zhazha.mybatis.bean.Employee">
<select id="selectBlog" resultType="com.zhazha.mybatis.bean.Employee">
SELECT te.id, te.last_name AS lastName, te.email, te.gender FROM tbl_employee te WHERE te.id = #{id}
</select>
</mapper>
新方式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接口 -->
<mapper namespace="com.zhazha.mapper.EmployeeMapper">
<!-- get mapper方法的函数名称 -->
<select id="get" resultType="com.zhazha.mybatis.bean.Employee">
SELECT te.id, te.last_name AS lastName, te.email, te.gender FROM tbl_employee te WHERE te.id = #{id}
</select>
</mapper>
mybatis的sql映射文件
<?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">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="EmployeeMapper.xml" />
<mapper resource="Employee.xml" />
</mappers>
</configuration>
log4Jxml配置文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<param name="Encoding" value="UTF-8" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) " />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="info" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>
- mybatis初始化过程源码理解
- mybatis调用过程
上面就是sql语句存放位置和方法签名存放位置数据结构
