idea： Java： 创建一个项目并完成对用户表 的增删改查 用户表字段 ID username password 详细过程

好的，以下是在IntelliJ IDEA中创建Java项目并完成对用户表的增删改查的详细过程：

1. 打开IntelliJ IDEA，点击“Create New Project”创建一个新项目。

2. 在“New Project”窗口中选择“Java”并设置项目名称和路径，然后点击“Next”。

3. 在“Project SDK”中选择您的Java开发环境，然后点击“Next”。

4. 在“Additional Libraries and Frameworks”中选择“Maven”，然后点击“Next”并完成项目创建。

5. 在创建的项目中添加MySQL数据库连接驱动的Maven依赖。

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.23</version>
</dependency>

6. 在项目中创建用户表对应的Java实体类，代码如下：

public class User {
    private int id;
    private String username;
    private String password;

    public User() {
    }

    public User(int id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
    }

    //省略getter和setter方法
}

7. 在项目中创建数据库连接工具类，代码如下：

public class DBUtil {
    private static final String URL = "jdbc:mysql://localhost:3306/user?useSSL=false&serverTimezone=UTC";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";

    public static Connection getConnection() throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.cj.jdbc.Driver");
        return DriverManager.getConnection(URL, USERNAME, PASSWORD);
    }

    public static void close(Connection conn, PreparedStatement pstmt, ResultSet rs) {
        try {
            if (rs != null) {
                rs.close();
            }
            if (pstmt != null) {
                pstmt.close();
            }
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

8. 在项目中创建用户表的增删改查操作类，代码如下：

public class UserDao {
    public void addUser(User user) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "INSERT INTO user_table(username, password) VALUES(?, ?)";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, user.getUsername());
            pstmt.setString(2, user.getPassword());
            pstmt.executeUpdate();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn, pstmt, null);
        }
    }

    public void deleteUser(int id) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "DELETE FROM user_table WHERE id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn, pstmt, null);
        }
    }

    public void updateUser(User user) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "UPDATE user_table SET username=?, password=? WHERE id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, user.getUsername());
            pstmt.setString(2, user.getPassword());
            pstmt.setInt(3, user.getId());
            pstmt.executeUpdate();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn, pstmt, null);
        }
    }

    public User getUserById(int id) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        User user = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "SELECT * FROM user_table WHERE id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            rs = pstmt.executeQuery();
            if (rs.next()) {
                user = new User();
                user.setId(rs.getInt("id"));
                user.setUsername(rs.getString("username"));
                user.setPassword(rs.getString("password"));
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn, pstmt, rs);
        }
        return user;
    }
}

9. 在项目中实现用户表的增删改查操作，代码如下：

public class Main {
    public static void main(String[] args) {
        UserDao userDao = new UserDao();

        //增加用户
        User user1 = new User(1, "user1", "123456");
        userDao.addUser(user1);

        //删除用户
        userDao.deleteUser(1);

        //修改用户
        User user2 = new User(2, "user2", "654321");
        userDao.updateUser(user2);

        //查询用户
        User user3 = userDao.getUserById(2);
        System.out.println("id:" + user3.getId() + ", username:" + user3.getUsername() + ", password:" + user3.getPassword());
    }
}

以上是在IntelliJ IDEA中创建Java项目并完成对用户表的增删改查的详细过程，希望能对您有所帮助。