用Java写一个关于employee表的增删改查

在Java中，我们可以使用JDBC（Java Database Connectivity）来操作数据库，这里我将给出一个简单的Employee表的CRUD操作示例，假设我们有一个Employee表，包含id、name和email字段。

首先，你需要导入相关的包，并设置数据库连接：

import java.sql.*;

public class EmployeeDAO {
    private Connection connection;

    // 构造函数获取数据库连接
    public EmployeeDAO(Connection conn) {
        this.connection = conn;
    }

    // 插入员工数据
    public void insert(Employee employee) throws SQLException {
        String sql = "INSERT INTO employee (id, name, email) VALUES (?, ?, ?)";
        try (PreparedStatement pstmt = connection.prepareStatement(sql)) {
            pstmt.setInt(1, employee.getId());
            pstmt.setString(2, employee.getName());
            pstmt.setString(3, employee.getEmail());
            pstmt.executeUpdate();
        }
    }

    // 更新员工信息
    public void update(Employee employee) throws SQLException {
        String sql = "UPDATE employee SET name = ?, email = ? WHERE id = ?";
        try (PreparedStatement pstmt = connection.prepareStatement(sql)) {
            pstmt.setString(1, employee.getName());
            pstmt.setString(2, employee.getEmail());
            pstmt.setInt(3, employee.getId());
            pstmt.executeUpdate();
        }
    }

    // 删除员工
    public void delete(int id) throws SQLException {
        String sql = "DELETE FROM employee WHERE id = ?";
        try (PreparedStatement pstmt = connection.prepareStatement(sql)) {
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        }
    }

    // 查询所有员工
    public List<Employee> getAll() throws SQLException {
        List<Employee> employees = new ArrayList<>();
        String sql = "SELECT * FROM employee";
        try (Statement stmt = connection.createStatement();
             ResultSet rs = stmt.executeQuery(sql)) {
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String email = rs.getString("email");
                employees.add(new Employee(id, name, email));
            }
        }
        return employees;
    }
}

这个类中，每个方法对应着数据库操作的SQL语句。注意这只是一个基本示例，实际应用中还需要处理异常并添加事务控制。