JDBC、Hibernate 和 MyBatis 在云原生架构中的应用

import java.sql.*;

public class JdbcExample {
    public static void main(String[] args) throws SQLException {
        // 加载 JDBC 驱动程序
        Class.forName("com.mysql.cj.jdbc.Driver");

        // 建立数据库连接
        Connection connection = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/test", "root", "password");

        // 创建 Statement 对象
        Statement statement = connection.createStatement();

        // 执行查询
        ResultSet resultSet = statement.executeQuery("SELECT * FROM users");

        // 处理查询结果
        while (resultSet.next()) {
            System.out.println(resultSet.getString("name"));
        }

        // 关闭资源
        resultSet.close();
        statement.close();
        connection.close();
    }
}

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateExample {
    public static void main(String[] args) {
        // 创建 Hibernate 配置对象
        Configuration configuration = new Configuration();

        // 添加要映射的类
        configuration.addAnnotatedClass(User.class);

        // 创建 SessionFactory
        SessionFactory sessionFactory = configuration.buildSessionFactory();

        // 打开 Session
        Session session = sessionFactory.openSession();

        // 创建新的 User 对象并保存到数据库
        User user = new User();
        user.setName("John Doe");
        session.save(user);

        // 提交事务
        session.getTransaction().commit();

        // 查找并打印已保存的用户
        User savedUser = session.get(User.class, user.getId());
        System.out.println(savedUser.getName());

        // 关闭 Session
        session.close();

        // 关闭 sessionFactory
        sessionFactory.close();
    }
}

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisExample {
    public static void main(String[] args) throws IOException {
        // 加载 MyBatis 配置文件
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(Resources.getResourceAsStream("mybatis-config.xml"));

        // 打开 Session
        SqlSession session = factory.openSession();

        // 执行查询
        List<User> users = session.selectList("com.example.mapper.UserMapper.findAll");

        // 处理查询结果
        for (User user : users) {
            System.out.println(user.getName());
        }

        // 提交事务
        session.commit();

        // 关闭 Session
        session.close();
    }
}