利用JDBC连接数据库创建一个员工信息系统并实现基本的增删改查

好的，下面是一个简单的员工信息系统的示例，包括了基本的增删改查操作：

1. 首先，我们需要建立一个名为 `Employee` 的实体类，用于表示员工信息：

public class Employee {
    private int id;
    private String name;
    private int age;
    private String gender;

    public Employee(int id, String name, int age, String gender) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.gender = gender;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getGender() {
        return gender;
    }
}

2. 接下来，我们需要建立一个名为 `EmployeeDao` 的 DAO 类，用于实现对员工信息的增删改查操作。在该类中，我们需要建立连接数据库的方法以及对应的增删改查方法：

public class EmployeeDao {
    private Connection conn;

    public EmployeeDao() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/employees", "root", "password");
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }

    public void add(Employee employee) {
        try {
            PreparedStatement ps = conn.prepareStatement("INSERT INTO employee VALUES (?, ?, ?, ?)");
            ps.setInt(1, employee.getId());
            ps.setString(2, employee.getName());
            ps.setInt(3, employee.getAge());
            ps.setString(4, employee.getGender());
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void delete(int id) {
        try {
            PreparedStatement ps = conn.prepareStatement("DELETE FROM employee WHERE id = ?");
            ps.setInt(1, id);
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void update(Employee employee) {
        try {
            PreparedStatement ps = conn.prepareStatement("UPDATE employee SET name = ?, age = ?, gender = ? WHERE id = ?");
            ps.setString(1, employee.getName());
            ps.setInt(2, employee.getAge());
            ps.setString(3, employee.getGender());
            ps.setInt(4, employee.getId());
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public Employee getById(int id) {
        try {
            PreparedStatement ps = conn.prepareStatement("SELECT * FROM employee WHERE id = ?");
            ps.setInt(1, id);
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                return new Employee(rs.getInt("id"), rs.getString("name"), rs.getInt("age"), rs.getString("gender"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public List<Employee> getAll() {
        List<Employee> employees = new ArrayList<>();
        try {
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM employee");
            while (rs.next()) {
                employees.add(new Employee(rs.getInt("id"), rs.getString("name"), rs.getInt("age"), rs.getString("gender")));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return employees;
    }
}

3. 最后，我们可以在 `main` 方法中调用 `EmployeeDao` 的方法来执行相应的操作：

public static void main(String[] args) {
    EmployeeDao dao = new EmployeeDao();

    // 添加员工信息
    dao.add(new Employee(1, "张三", 20, "男"));

    // 获取指定 ID 的员工信息
    Employee employee = dao.getById(1);
    System.out.println(employee.getName() + " " + employee.getAge() + " " + employee.getGender());

    // 修改员工信息
    dao.update(new Employee(1, "李四", 22, "女"));

    // 删除员工信息
    dao.delete(1);

    // 获取所有的员工信息
    List<Employee> employees = dao.getAll();
    for (Employee e : employees) {
        System.out.println(e.getName() + " " + e.getAge() + " " + e.getGender());
    }
}

以上就是一个简单的基于 JDBC 的员工信息系统的示例，您可以根据自己的需求进行相应的修改和优化。