Mybais的增删改查CRUD

在这里 首先要搭建好Mybatis的配置环境

一、增加

UerDao接口中:

 public void addUser(User user);

 映射配置文件UserDao.xml中:

<insert id="addUser" parameterType="eud.rk.domain.User">
       insert into user (username,address,sex,birthday) values(#{username},#{address},#{sex},#{birthday});
    </insert>

测试类:

@Test
    public void testSave() throws IOException {
        User user=new User();
        user.setUsername("张三");
        user.setAddress("汉中市西乡县");
        user.setSex("男");
        user.setBirthday(new Date());

        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //5、执行添加方法
        userDao.addUser(user);
        //提交事务
        sqlSession.commit();

        //6、释放资源
        sqlSession.close();
        in.close();
    }

二、删除----根据id删除

UerDao接口中:

public void deleteUser(Integer id);

映射配置文件UserDao.xml中:

    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete  from user where id=#{id};
    </delete>

测试类:

 @Test
    public void testDelete() throws IOException {
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //执行修改操作
        userDao.deleteUser(41);
        //提交事务
        sqlSession.commit();
        //6、释放资源
        sqlSession.close();
        in.close();
    }

三、修改

UerDao接口中:

   public void updateUser(User user);

映射配置文件UserDao.xml中:

<update id="updateUser" parameterType="eud.rk.domain.User">
        update user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday} where id=#{id};
    </update>

测试类:

@Test
    public void testUpdate() throws IOException {
        User user=new User();
        user.setUsername("李四");
        user.setAddress("陕西省宝鸡市");
        user.setSex("女");
        user.setId(41);
        user.setBirthday(new Date());
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //执行修改操作
        userDao.updateUser(user);
        //提交事务
        sqlSession.commit();
        //6、释放资源
        sqlSession.close();
        in.close();
    }

四、查询

UerDao接口中:

查询所有:

public List<User> findAll();

查询一个:

public User findById(Integer id);

 映射配置文件UserDao.xml中:

<select id="findAll" resultType="eud.rk.domain.User">
        select * from user;
    </select>

<select id="findById" resultType="eud.rk.domain.User">
        select * from user where id=#{id};
    </select>

测试类:

 @Test
    public void testFindAll() throws IOException {
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //5、执行查询所有的方法
        List<User> users = userDao.findAll();

        for (User user : users) {
            System.out.println(user);
        }
        sqlSession.close();
        in.close();
    }

  @Test
    public void testFindbyId() throws IOException {
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        User user = userDao.findById(52);
        System.out.println(user);
        //6、释放资源
        sqlSession.close();
        in.close();
    }

模糊查询

UerDao接口中:

 List<User> findByName(String username);

 映射配置文件UserDao.xml中:

<select id="findByName" resultType="eud.rk.domain.User" parameterType="String">
        select * from user where username like #{name}
    </select>

      查询语句也可以替换成: select * from user where username like '%{value}%'

测试类:

 public void testFindbyUsername() throws IOException {
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        List<User> users = userDao.findByName("%王%");
        for (User user : users) {
            System.out.println(user);
        }
        //6、释放资源
        sqlSession.close();
        in.close();
    }

查询总记录条数:

UerDao接口中:

public int findTotal();

映射配置文件UserDao.xml中:

<select id="findTotal" resultType="int">
        select count(id) from user;
    </select>

测试类:

@Test
    public void testFindTotal() throws IOException {
        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        int total = userDao.findTotal();
        System.out.println(total);
        //6、释放资源
        sqlSession.close();
        in.close();
    }

OGNL表达式：它是通过对象的取值来获取数据。在写法上把get给省略了

根据QueryVo的条件查询模糊用户

QueryVo对象:

public class QueryVo {
    private User user=new User();

    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
}

UerDao接口中:

   public List<User> findUserByVo(QueryVo vo);

映射配置文件UserDao.xml中:

<select id="findUserByVo" parameterType="eud.rk.domain.QueryVo" resultType="eud.rk.domain.User">
        select * from user where username like #{user.username};
    </select>

测试类:

@Test
    public void testFindByVo() throws IOException {
        QueryVo vo=new QueryVo();
        User user = vo.getUser();
        user.setUsername("%王%");
        vo.setUser(user);

        //1、读取配置文件，生成字节输入流
        InputStream in= Resources.getResourceAsStream("rk.xml");
        //2、获取sqlSessionfactory
        SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(in);
        //3、获取sqlsession对象
        SqlSession sqlSession = factory.openSession();
        //4、获取dao的代理对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        List<User> users = userDao.findUserByVo(vo);
        for (User u : users) {
            System.out.println(u);
        }

        //6、释放资源
        sqlSession.close();
        in.close();
    }