请以java和mysql做一个”管理码头系统“

好的，我可以给你提供一个简单的示例代码，用Java和MySQL实现一个简单的管理码头系统。由于没有具体的需求，所以这个系统只是一个基础的框架，你可以在此基础上进行修改和扩展。

首先，我们需要建立一个MySQL数据库，用于存储码头系统的数据。假设我们已经创建了一个名为"port_management"的数据库，包含两个表："ship"和"berth"，分别用于存储船只和停泊位的信息。以下是这两个表的DDL语句：

CREATE TABLE ship (
    id INT(11) NOT NULL AUTO_INCREMENT,
    name VARCHAR(50) NOT NULL,
    cargo VARCHAR(50) NOT NULL,
    berth_id INT(11) NOT NULL,
    PRIMARY KEY (id),
    FOREIGN KEY (berth_id) REFERENCES berth(id)
);

CREATE TABLE berth (
    id INT(11) NOT NULL AUTO_INCREMENT,
    number INT(11) NOT NULL,
    capacity INT(11) NOT NULL,
    PRIMARY KEY (id)
);

接下来，我们需要创建一个Java项目，并添加MySQL驱动程序。在这个项目中，我们将创建两个类："Ship"和"Berth"，分别对应数据库中的两个表。这两个类都包含一些基本的属性和方法，用于对船只和停泊位进行管理。

Ship类的实现如下：

import java.sql.*;

public class Ship {
    private int id;
    private String name;
    private String cargo;
    private int berthId;

    public Ship(int id, String name, String cargo, int berthId) {
        this.id = id;
        this.name = name;
        this.cargo = cargo;
        this.berthId = berthId;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getCargo() {
        return cargo;
    }

    public int getBerthId() {
        return berthId;
    }

    public void setBerthId(int berthId) {
        this.berthId = berthId;
    }

    public static Ship[] getAllShips() {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost/port_management", "root", "password");
            stmt = conn.createStatement();
            rs = stmt.executeQuery("SELECT * FROM ship");
            int count = getRowCount(rs);
            Ship[] ships = new Ship[count];
            int i = 0;
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String cargo = rs.getString("cargo");
                int berthId = rs.getInt("berth_id");
                ships[i++] = new Ship(id, name, cargo, berthId);
            }
            return ships;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } finally {
            closeResultSet(rs);
            closeStatement(stmt);
            closeConnection(conn);
        }
    }

    public static Ship getShipById(int id) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost/port_management", "root", "password");
            stmt = conn.prepareStatement("SELECT * FROM ship WHERE id = ?");
            stmt.setInt(1, id);
            rs = stmt.executeQuery();
            if (rs.next()) {
                String name = rs.getString("name");
                String cargo = rs.getString("cargo");
                int berthId = rs.getInt("berth_id");
                return new Ship(id, name, cargo, berthId);
            } else {
                return null;
            }
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } finally {
            closeResultSet(rs);
            closeStatement(stmt);
            closeConnection(conn);
        }
    }

    public void save() {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost/port_management", "root", "password");
            if (id == 0) {
                stmt = conn.prepareStatement("INSERT INTO ship (name, cargo, berth_id) VALUES (?, ?, ?)", Statement.RETURN_GENERATED_KEYS);
                stmt.setString(1, name);
                stmt.setString(2, cargo);
                stmt.setInt(3, berthId);
                stmt.executeUpdate();
                rs = stmt.getGeneratedKeys();
                if (rs.next()) {
                    id = rs.getInt(1);
                }
            } else {
                stmt = conn.prepareStatement("UPDATE ship SET name = ?, cargo = ?, berth_id = ? WHERE id = ?");
                stmt.setString(1, name);
                stmt.setString(2, cargo);
                stmt.setInt(3, berthId);
                stmt.setInt(4, id);
                stmt.executeUpdate();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeResultSet(rs);
            closeStatement(stmt);
            closeConnection(conn);
        }
    }

    public void delete() {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost/port_management", "root", "password");
            stmt = conn.prepareStatement("DELETE FROM ship WHERE id = ?");
            stmt.setInt(1, id);
            stmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeStatement(stmt);
            closeConnection(conn);
        }
    }

    private static int getRowCount(ResultSet rs) throws SQLException {
        int rowCount;
        int currentRow = rs.getRow();
        if (currentRow == 0) {
            rs.last();
            rowCount = rs.getRow();
            rs.beforeFirst();
        } else {
            rowCount = currentRow;
        }
        return rowCount;
    }

    private static void closeResultSet(ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    private static void closeStatement(Statement stmt) {
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    private static void closeConnection(Connection conn) {
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

Berth类的实现与Ship类类似，这里不再赘述。

最后，我们需要创建一个包含main方法的类，用于测试这些类的功能。以下是一个简单的示例：

public class Main {
    public static void main(String[] args) {
        Ship[] ships = Ship.getAllShips();
        for (Ship ship : ships) {
            System.out.println(ship.getName() + " is currently at berth " + ship.getBerthId());
        }
        Ship ship1 = new Ship(0, "Cargo Ship 1", "Oil", 2);
        ship1.save();
        Ship ship2 = Ship.getShipById(1);
        ship2.setBerthId(3);
        ship2.save();
        Ship ship3 = Ship.getShipById(2);
        ship3.delete();
    }
}

这个示例程序会输出当前所有船只的信息，并进行一些简单的添加、修改和删除操作。当然，这只是一个简单的示例，实际应用中可能需要更多的功能和安全性措施。