mybatis 快速入门

1 . 定义  java实体类 User，建立user表 读者请自行完成准备工作。

 User 类 有 id, name,age 属性

 user  表 中 id,name,age字段  id自增长 

 

2.  定义sql映射XML  userMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE *** >

<!--  

     namespace 默认取 userMapper.xml的 全路径 + "." +  文件名去除后缀 即userMapper

-->

<mapper namespace ="com.atguigu.mybatis.userMapper">

<insert id="insertUser" parameterType="com.atguigu.ibatis.bean.User">   

  insert into users(name,age) values (#{name},#{age});

</insert>

 

<delete id="delUser" parameterType="int">

   delete from users where id =#{id}

</delete>

 

<update id="updateUser" parameterType="com.atguigu.ibatis.bean.User">

     update users set name=#{name}, age=#{age} where id=#{id}

</update>

 

<select id="selUser" parameterType ="int"  resultType="com.atguigu.ibatis.bean.User">

     select * from users where id=#{id}

</select>

 

<select id="getAllUsers" resultType="com.atguigu.ibatis.bean.User">

  select * from users

</select>

</mapper>

 

3.定义数据源连接池 相关配置

  注册相关xml文件

<?xm l version = "1.0" encoding ="UTF-8" ?>

 <configuration>

<environments default ="development">

  <environment id="development">

       <transactionManager type="JDBC"  />

      <datasource type="POOLED" >

         <property name="driverClass" value=""  />

         <property name="jdbcUrl" value=""  />

         <property name="user" value=""  />

         <property name="password" value=""  />

      </datasource>

  </environment>

</environments>

</configuration>

 

 

//注册相关 mapper xml

<mappers>

 <mapper resource = "com/atguigu/mybatis/userMapper.xml" />   //路径名

</mappers>

</xml>

 

 

 

4. 编写测试代码

@Test   

public void testAdd(){

       SqlSessionFactory factory = MybatisUtils.getFactory();

      SqlSession session = factory.openSession();  //默认手动提交事务 

      String statement = "com.atguigu.mybatis.userMapper.addUser";   //namespace+ "." + id

      session.insert(statement,new User(-1,"kk",22)）;

      session.commit();  //提交事务

     session.close();

   }

 

@Test   

public void testDel(){

       SqlSessionFactory factory = MybatisUtils.getFactory();

      SqlSession session = factory.openSession();  //默认手动提交事务 

      String statement = "com.atguigu.mybatis.userMapper.delUser";

      session.insert(statement,2);

      session.commit();  //提交事务

     session.close();

   }

 

   @Test

   public void testUpdate(){

      SqlSessionFactory factory = MybatisUtils.getFactory();

      SqlSession session = factory.openSession(true);  //设置自动提交

      String statement = "com.atguigu.mybatis.userMapper.updateUser;

     session.update(statement, new User(4,"kk4",333));

      session.close();

}

 

 public void testGetUser(){

     SqlSessionFactory factory = MybatisUtils.getFactory();

    SqlSession session = factory.openSession();

    

   String statement = "com.atguigu.mybatis.userMapper.selUser";

   User user = session.selectOne(statement, 1);

  session.close();

  System.out.println(user);

 

}

 

@Test

public void getAllUsers(){  

     SqlSessionFactory factory = MybatisUtils.getFactory();

      SqlSession session = factory.openSession(true);  //设置自动提交

      String statement = "com.atguigu.mybatis.userMapper.getAllUsers";

      List<User> users = session.selectList(statement);

      session.close();

}

 

mybatis 单字符问题：：

'N'.toString()

test='************          "Y" ******************'