分别使用JDBC和C3P0数据库连接池完成以下数据库操作，具体要求如下： 1）在mysql数据库中创建mydb数据库，创建用户表t_user ，表字段如下： 序号 字段名 类型 是否主键、空 1 id int 主键，自增长 2 name Varchar(20) NOT NULL 3 password Varchar(20) NOT NULL 4 email Varchar(20) DEFAULT NULL 2）创建User类，用于封装表数据; 3）编写JDBCUtils工具类，类中要包含获取连接和释放资源的方法 4）创建一个UserDao类，在该类中编写对数据库进行增删改查的方法，包括insert（User user）、update(User user)、delete（int id）、queryAll( )等方法,分别实现插入、更新、删除和查询所有记录的方法。 5）创建测试类Test1，对上述UserDao中定义的方法进行测试输出。 6）尝试使用C3P0数据库连接池和DBUtils工具，完成上述一样的操作，对应dao类为C3P0UserDao，C3P0Utils工具类获取数据源。 7）在C3P0UserDao类中编写对数据库进行增删改查的方法，包括insert（User user）、update(User user)、delete（int id）、queryAll( )等方法,分别实现插入、更新、删除和查询所有记录的方法。 创建测试类Test2，对上述C3P0UserDao中定义的方法进行测试输出

由于篇幅较长，我只能提供代码示例，希望对你有所帮助。

使用JDBC实现：

User类：

public class User {
    private int id;
    private String name;
    private String password;
    private String email;

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

    // getter and setter methods
}

JDBCUtils工具类：

public class JDBCUtils {
    private static final String URL = "jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC";
    private static final String USER = "root";
    private static final String PASSWORD = "password";

    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(URL, USER, PASSWORD);
    }

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

UserDao类：

public class UserDao {
    public void insert(User user) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = JDBCUtils.getConnection();
            String sql = "INSERT INTO t_user(name, password, email) VALUES (?, ?, ?)";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, user.getName());
            pstmt.setString(2, user.getPassword());
            pstmt.setString(3, user.getEmail());
            int rows = pstmt.executeUpdate();
            System.out.println("Inserted " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(conn, pstmt, null);
        }
    }

    public void update(User user) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = JDBCUtils.getConnection();
            String sql = "UPDATE t_user SET name=?, password=?, email=? WHERE id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, user.getName());
            pstmt.setString(2, user.getPassword());
            pstmt.setString(3, user.getEmail());
            pstmt.setInt(4, user.getId());
            int rows = pstmt.executeUpdate();
            System.out.println("Updated " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(conn, pstmt, null);
        }
    }

    public void delete(int id) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = JDBCUtils.getConnection();
            String sql = "DELETE FROM t_user WHERE id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            int rows = pstmt.executeUpdate();
            System.out.println("Deleted " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(conn, pstmt, null);
        }
    }

    public List<User> queryAll() {
        List<User> userList = new ArrayList<>();
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            conn = JDBCUtils.getConnection();
            String sql = "SELECT id, name, password, email FROM t_user";
            stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String password = rs.getString("password");
                String email = rs.getString("email");
                User user = new User(id, name, password, email);
                userList.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(conn, stmt, rs);
        }
        return userList;
    }
}

测试类Test1：

public class Test1 {
    public static void main(String[] args) {
        UserDao userDao = new UserDao();

        // insert
        User user1 = new User(0, "Alice", "123456", "alice@example.com");
        userDao.insert(user1);
        User user2 = new User(0, "Bob", "abcdef", null);
        userDao.insert(user2);

        // update
        User user3 = new User(1, "Alice2", "654321", "alice2@example.com");
        userDao.update(user3);

        // queryAll
        List<User> userList = userDao.queryAll();
        for (User user : userList) {
            System.out.println(user.getId() + "\t" + user.getName() + "\t" + user.getPassword() + "\t" + user.getEmail());
        }

        // delete
        userDao.delete(2);
    }
}

使用C3P0实现：

C3P0Utils工具类：

public class C3P0Utils {
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();

    public static DataSource getDataSource() {
        return dataSource;
    }
}

C3P0UserDao类：

public class C3P0UserDao {
    private QueryRunner runner = new QueryRunner(C3P0Utils.getDataSource());

    public void insert(User user) {
        String sql = "INSERT INTO t_user(name, password, email) VALUES (?, ?, ?)";
        try {
            int rows = runner.update(sql, user.getName(), user.getPassword(), user.getEmail());
            System.out.println("Inserted " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void update(User user) {
        String sql = "UPDATE t_user SET name=?, password=?, email=? WHERE id=?";
        try {
            int rows = runner.update(sql, user.getName(), user.getPassword(), user.getEmail(), user.getId());
            System.out.println("Updated " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void delete(int id) {
        String sql = "DELETE FROM t_user WHERE id=?";
        try {
            int rows = runner.update(sql, id);
            System.out.println("Deleted " + rows + " row(s).");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public List<User> queryAll() {
        String sql = "SELECT id, name, password, email FROM t_user";
        try {
            return runner.query(sql, new BeanListHandler<>(User.class));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
}

测试类Test2：

public class Test2 {
    public static void main(String[] args) {
        C3P0UserDao userDao = new C3P0UserDao();

        // insert
        User user1 = new User(0, "Alice", "123456", "alice@example.com");
        userDao.insert(user1);
        User user2 = new User(0, "Bob", "abcdef", null);
        userDao.insert(user2);

        // update
        User user3 = new User(1, "Alice2", "654321", "alice2@example.com");
        userDao.update(user3);

        // queryAll
        List<User> userList = userDao.queryAll();
        for (User user : userList) {
            System.out.println(user.getId() + "\t" + user.getName() + "\t" + user.getPassword() + "\t" + user.getEmail());
        }

        // delete
        userDao.delete(2);
    }
}