mybatis学习笔记(2)搭建环境

Posted on 2023-03-19 01:01 弯弓射雕的男人阅读(12) 评论(0) 编辑收藏举报

搭建环境流程如下四点：

创建maven工程并导入坐标

<dependencies>
     
           <dependency>
               <groupId>org.mybatis</groupId>
               <artifactId>mybatis</artifactId>
               <version>3.4.5</version>
           </dependency>
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
               <version>5.1.43</version>
           </dependency>
     
           <dependency>
               <groupId>log4j</groupId>
               <artifactId>log4j</artifactId>
               <version>1.2.12</version>
           </dependency>
     
           <dependency>
               <groupId>junit</groupId>
               <artifactId>junit</artifactId>
               <version>4.10</version>
           </dependency>
     
</dependencies>

　创建实体类和Mapper的接口

public class User implements Serializable {
         
    private int id ;
    private String username;
    ......
}

public interface IUserMapper {
    /**
    * 查询所有操作
    * @return
    */
    List<User> findAll();
}

　　创建mybatis的主配置文件

<configuration>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置Mysql的环境-->
        <environment id="mysql">
            <!--配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源(连接池)-->
            <dataSource type="POOLED">
                <!--配置连接数据库的四个基本信息-->
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/db1" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
 
    <mappers>
        <mapper resource="Mybatis/IuserMapper.xml" />
    </mappers>
 
</configuration>

　　创建映射配置文件

<mapper namespace="com.Mapper.IUserMapper" >
    <select id="findAll" resultType="com.Pojo.User" >
        select * from usr
    </select>
</mapper>

　　测试方法

......
 
InputStream in = Resources.getResourceAsStream("mybatis/MapperConfig.xml");
//创建SqlSessionFactory工厂
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(in);
//使用工厂生产SqlSession对象
SqlSession session = factory.openSession();
//使用SqlSession创建Mapper接口的代理对象
UserMapper userMapper = session.getMapper(UserMapper.class);
//使用代理对象执行方法
List<mybatis_user> users = userMapper.findAll();
for (mybatis_user muser : users){
    System.out.println(muser);
}
session.close();
in.close();
 
......