java增加删除修改查询

Java中可以使用以下方式来实现增加、删除、修改和查询数据：

1. 增加数据：可以使用JDBC或Hibernate等框架来连接数据库，然后通过SQL语句或ORM映射来实现数据的插入，例如：

使用JDBC：

String sql = "INSERT INTO user(name, age, gender) VALUES (?, ?, ?)";
try (Connection conn = DriverManager.getConnection(url, username, password);
     PreparedStatement ps = conn.prepareStatement(sql)) {
    ps.setString(1, "Tom");
    ps.setInt(2, 20);
    ps.setString(3, "Male");
    int result = ps.executeUpdate();
    if (result > 0) {
        System.out.println("Insert succeeded.");
    } else {
        System.out.println("Insert failed.");
    }
} catch (SQLException e) {
    e.printStackTrace();
}

使用Hibernate：

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
User user = new User("Tom", 20, "Male");
session.save(user);
tx.commit();
session.close();

2. 删除数据：同样可以使用JDBC或Hibernate等框架来实现数据的删除，例如：

使用JDBC：

String sql = "DELETE FROM user WHERE name=?";
try (Connection conn = DriverManager.getConnection(url, username, password);
     PreparedStatement ps = conn.prepareStatement(sql)) {
    ps.setString(1, "Tom");
    int result = ps.executeUpdate();
    if (result > 0) {
        System.out.println("Delete succeeded.");
    } else {
        System.out.println("Delete failed.");
    }
} catch (SQLException e) {
    e.printStackTrace();
}

使用Hibernate：

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
User user = session.load(User.class, 1L);
session.delete(user);
tx.commit();
session.close();

3. 修改数据：同样可以使用JDBC或Hibernate等框架来实现数据的修改，例如：

使用JDBC：

String sql = "UPDATE user SET age=? WHERE name=?";
try (Connection conn = DriverManager.getConnection(url, username, password);
     PreparedStatement ps = conn.prepareStatement(sql)) {
    ps.setInt(1, 21);
    ps.setString(2, "Tom");
    int result = ps.executeUpdate();
    if (result > 0) {
        System.out.println("Update succeeded.");
    } else {
        System.out.println("Update failed.");
    }
} catch (SQLException e) {
    e.printStackTrace();
}

使用Hibernate：

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
User user = session.load(User.class, 1L);
user.setAge(21);
session.update(user);
tx.commit();
session.close();

4. 查询数据：同样可以使用JDBC或Hibernate等框架来实现数据的查询，例如：

使用JDBC：

String sql = "SELECT * FROM user";
try (Connection conn = DriverManager.getConnection(url, username, password);
     PreparedStatement ps = conn.prepareStatement(sql)) {
    ResultSet rs = ps.executeQuery();
    while (rs.next()) {
        System.out.println("ID: " + rs.getLong("id"));
        System.out.println("Name: " + rs.getString("name"));
        System.out.println("Age: " + rs.getInt("age"));
        System.out.println("Gender: " + rs.getString("gender"));
    }
} catch (SQLException e) {
    e.printStackTrace();
}

使用Hibernate：

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Query query = session.createQuery("FROM User");
List<User> userList = query.list();
for (User user : userList) {
    System.out.println("ID: " + user.getId());
    System.out.println("Name: " + user.getName());
    System.out.println("Age: " + user.getAge());
    System.out.println("Gender: " + user.getGender());
}
tx.commit();
session.close();