Mybatis

Posted 2021-06-16 兴贤博客

Mybatis

User.java类

定义数据属性：

形参：

public class User {
    private int id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;
    public User()
    {
        super();    
    }

实参：

    public User(String username, Date birthday, String sex, String address){
    this.username = username;
    this.birthday = birthday;
    this.sex = sex;
    this.address = address;
}

App.java

编写测试类：

  public class App {
  public static void main(String[] args){
  //解析全局配置文件
      String resource = "mybatis-config.xml";//全局配置文件的路径（相对于src的路径）
      try {
  InputStream inputStream =Resources.getResourceAsStream(resource);
  //输入流实例通过getResourceAsStream（）获取配置文件
  SqlSessionFactory sqlSessionFactory = new       SqlSessionFactoryBuilder().build(inputStream);
  //SqlSessionFactory实例可以通过 SqlSessionFactoryBuilder 获得
  //调用Dao层接口方法完成SQL执行
  SqlSession sqlSession = sqlSessionFactory.openSession();
  //从 SqlSessionFactory 中获取 SqlSession
  //shift+alt+1
  UserDao userdao = sqlSession.getMapper(UserDao.class);
  //SqlSession 实例来直接执行已映射的 SQL 语句
  //获取相应接口实现类的类对象
  List<User> ulist = userdao.getAll();
  System.out.println(ulist);
  }catch(Exception e) {
      e.printStackTrace();//try catch进行异常错误处理
  }
  }
}

操作

根据主键查询

1.UserDao.xml映射文件

2.UserDao.java接口方法

  User getUserById(int uid);

3.App2.java

public class App2 {
     UserDao userDao;//创建全局变量
     SqlSession sqlSession;//创建全局变量
    public void setup() throws IOException {
     String resource = "mybatis-config.xml";          
      InputStream inputStream =Resources.getResourceAsStream(resource);
     SqlSessionFactory sqlSessionFactory = new   SqlSessionFactoryBuilder().build(inputStream);
      sqlSession = sqlSessionFactory.openSession();
      userDao = sqlSession.getMapper(UserDao.class);
}

根据主键保存

1.UserDao.xml映射文件

2.UserDao.java接口方法

 int saveUser(User user);

3.App2.java

  public void saveUser() {
             User user = new User("搜索",new Date(),"男","北京");
              int i = userDao.saveUser(user);
            sqlSession.commit();        //提交     
              System.out.println(user);//输出打印user表中数据  
  }

根据主键更新

1.UserDao.xml映射文件

 

 

2.UserDao.java接口方法

  int updateUser(User user);

3.App2.java

  public void update() {
          User user = new User();
          user.setId(1);
          user.setSex("男");
          user.setUsername("天天");
          userDao.updateUser(user);
          sqlSession.commit();
  }

根据主键删除

1.UserDao.xml映射文件

 

 

2.UserDao.java接口方法

int getDeleteById(User user);

3.App2.java

public void getDeleteById() {
          User user = userDao.getUserById(1);
          int i = userDao.getDeleteById(user);
            sqlSession.commit();
          System.out.println(user);
}