Mybatis實現單表的增刪改查

mybtis快速入門–查詢單表所有字段

①首先導入依賴

<dependencies>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.12</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.5</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
</dependencies>

②需要有接口 接口中有方法

新建四個包 web service dao domain

這個新寫的接口放入dao中

另外返回的list集合中的user也要進行創建 在domain中進行創建

public interface UserDao {
   public List<User> findAllUser();
}

③主配置文件–SqlSessionConfiguraction.xml , 直接new File 即可

<?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:///ssm"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
<!--建立和sql映射文件的關係-->
    <mappers>
        <mapper resource="UserDao.xml"/>
    </mappers>
</configuration>

④Sql配置文件 注意這個配置文件的名字要和接口名稱一致纔行

<?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.nantian.dao.UserDao">
    <select id="findAllUser" resultType="com.nantian.domain.User">
    select * from t_user
  </select>
</mapper>

⑤最後在寫一個測試類進行測試即可

   InputStream is = Resources.getResourceAsStream("SqlSessionConfiguraction.xml");
   SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
   SqlSessionFactory sqlSessionFactory = builder.build(is);
   SqlSession sqlSession = sqlSessionFactory.openSession();
   UserDao userDao = sqlSession.getMapper(UserDao.class);
   List<User> users = userDao.findAll();
   System.out.println(users);
   sqlSession.close();

總結一下:

主配置文件 :

首先主配置文件需要連接到數據庫 configuration , 然後在連接到Sql配置文件→mappers , resources寫sql配置文件

 <mappers>
        <mapper resource="UserDao.xml"/>
 </mappers>

Sql配置文件 :

關鍵字mapper , namespace找到唯一的接口 , id 是方法名 , 進一步定位 , resultType是返回值結果

如果是List<對象> 對象全限定類名 , 如果是基本類型 使用基本類型名稱

<mapper namespace="com.nantian.dao.UserDao">
    <select id="findAllUser" resultType="com.nantian.domain.User">
    select * from t_user
  </select>
</mapper>

mybatis增刪改查

只需要修改UserDao.xml 文件

以及測試文件即可

<mapper namespace="com.itheima.dao.UserDao">

  <select id="findAllUser" resultType="com.itheima.domain.User">
    select * from tbl_user;
  </select>

  <insert id="saveUser" parameterType="com.itheima.domain.User">
    insert into tbl_user VALUES (null,#{username},#{PASSWORD},#{gender},#{email},#{telephone});
  </insert>

  <delete id="deleteUserById" parameterType="int">
    delete from tbl_user where id= #{id};
  </delete>

  <update id="updateUser" parameterType="com.itheima.domain.User" >
    update tbl_user set username= #{username} where id=#{id};
  </update>
</mapper>

測試文件

public class test01 {
    @Before
    public void A() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfiguraction.xml");
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = builder.build(is);
         sqlSession = sqlSessionFactory.openSession();
    }
    private  SqlSession sqlSession;
    //增
    @Test
    public void saveUser() throws IOException {

        UserDao userDao = sqlSession.getMapper(UserDao.class);
        User user = new User();
        user.setUsername("張帥");
        user.setGender("男");
        user.setPassword("1111");
        user.setTelephone("13258960266");
        user.setEmail("[email protected]");
        userDao.saveUser(user);
        System.out.println(user);
        sqlSession.commit();
    }

    //刪
    @Test
    public void deleteUserById(){
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        userDao.deleteUserById(9);
        sqlSession.commit();
    }
    //改
    @Test
    public void updateUser(){
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        User user = new User();
        user.setUsername("james");
        userDao.updateUser(user);
        sqlSession.commit();
    }

    //查
    @Test
    public void  findAllUser() throws IOException {
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        List<User> users = userDao.findAllUser();
        System.out.println(users);
    }

    @After
    public  void B(){
        sqlSession.close();
    }
}

  parameterType:
        對象 : 全限定類名
        如果是基本數據類型 string 直接寫名稱即可(名稱不區分大小寫)
        TypeAliasRegistry 別名(外號)註冊器
    #{} 如果是對象類型 書寫 是get/set方法 去掉....
    #{} 如果參數只有一個 並且是基本數據類型 #{隨便寫}