MyBatis
创建
在pom.xml中添加依赖
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.32</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.13</version>
</dependency>
db.properties
jdbc.driverClass=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/数据库名?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&useSSL=false
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"> <!-- 有错误 -->
<configuration>
<!--引入外部配置文件 -->
<properties resource="db.properties"/>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<!-- 连接信息 -->
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql:///数据库名?useSSL=false"/>
<property name="username" value="root"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<!-- 注册UserMapper.xml -->
<mappers>
<!-- 加载Sql映射文件 -->
<mapper resource="UserMapper.xml"/>
</mappers>
</configuration>
Sql映射文件
UserMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- namespace命名空间 -->
<!--resultType：返回结果类型-->
<mapper namespace="com.cy.mybatis.mapper.UserMapper">
</mapper>
命名空间中的内容的格式
<select id="名" resultType="返回结果类型">
select * from 表名 where 字段名 = 内容
</select>
-
例
-
<mapper namespace="test"> <select id="selectUsers" resultType="User"> select * from demo1; </select> </mapper>
-
使用
- 获取SqlSessionFactory对象
try {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
throw new RuntimeException(e);
}
- 获取sqlSession对象，执行SQL语句
SqlSession sqlSession = sqlSessionFactory.openSession();
- 执行SQL语句
List<User> users = sqlSession.selectList("test.selectUsers");
//执行sql语句，此处执行了上文UserMapper.xml示例中的test
方法二：获取Mapper接口的代理对象
- 释放资源
sqlSession.close();
其他语句
insert
<insert id="add">
insert into demo1 values(id,name,password);
</insert>