java: DDD using sql server 2019 or Oracle21c

 

如何用工厂模式切换数据库系统

项目结构：

domain
--entities
----school.java
--repositories
----school.java
infrastructure
--database
-----duoraclehelper.java
--model
----school.java
--repositories
----Oracle
-------school.java
----Sqlserver
-------school.java
--common
----DatabaseType
--factories
----RepositoryFactory
--config
-----AppConfig

application
--server
-----school.java
presentation
--controllers
----school.java
--views
----school.java
main.java

 

 

/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/14 - 22:53
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : DatabaseType.java
 * explain   : 学习  枚举
 **/
package infrastructure.common;

/**
 *
 */
public enum DatabaseType {

    ORACLE,
    SQL_SERVER,
    MYSQL,
    POSTGRESQL,
    SQLSERVER,
    SQLITE
}


/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1 Neo4j
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/14 - 23:06
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : AppConfig.java
 * explain   : 学习  类
 **/

package infrastructure.config;

import infrastructure.common.DatabaseType;
import infrastructure.database.DatabaseConnectionFactory;
import infrastructure.factories.RepositoryFactory;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;


public class AppConfig {

    /**
     *
     */
    private static final String CONFIG_FILE = "application.properties";
    private static Properties properties;

    static {
        loadConfig();
        initializeComponents();
    }

    private static void loadConfig() {
        properties = new Properties();
        try (InputStream is = AppConfig.class.getClassLoader().getResourceAsStream(CONFIG_FILE)) {
            //AppConfig.class.getClassLoader()  src 下
            if (is != null) {
                properties.load(is);
            } else {
                throw new IOException("无法加载配置文件: " + CONFIG_FILE);
            }
        } catch (IOException e) {

            System.err.println("加载配置文件失败: " + CONFIG_FILE);
            System.err.println("使用默认配置");
            throw new RuntimeException("加载配置失败", e);

        }
    }

    private static void initializeComponents() {
        String dbType = properties.getProperty("default.database.type", "SQL_SERVER");
        DatabaseType databaseType;// = DatabaseType.valueOf(dbType.toUpperCase());

        try {
            databaseType = DatabaseType.valueOf(dbType.toUpperCase());
            System.out.println(dbType);

        } catch (IllegalArgumentException e) {
            System.err.println("无效的数据库类型配置: " + dbType);
            System.err.println("使用默认值: SQL_SERVER");
            databaseType = DatabaseType.SQL_SERVER;
        }
        DatabaseConnectionFactory.initialize(databaseType);
        RepositoryFactory.initialize(databaseType);
    }

    public static String getProperty(String key) {
        return properties.getProperty(key);
    }
}



/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1 Neo4j
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/14 - 23:02
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : DatabaseConfigManager.java
 * explain   : 学习  类
 **/

package infrastructure.config;

import infrastructure.database.DatabaseConnectionFactory;
import infrastructure.common.DatabaseType;
import infrastructure.factories.RepositoryFactory;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

public class DatabaseConfigManager {

    private static final String CONFIG_FILE = "application.properties";
    private static Properties properties;
    private static final Map<DatabaseType, Map<String, String>> dbConfigs = new HashMap<>();
    private static DatabaseType activeDbType;

    static {
        loadConfig();
        initializeDbConfigs();
        // 设置默认数据库
        String defaultType = properties.getProperty("default.database.type", "SQL_SERVER");
        activeDbType = DatabaseType.valueOf(defaultType.toUpperCase());
    }

    private static void loadConfig() {
        properties = new Properties();


        String host = AppConfig.getProperty("sqlserver.host");
        String port = AppConfig.getProperty("sqlserver.port");
        String name = AppConfig.getProperty("sqlserver.name");
        System.out.println("host:"+host + ":" + port);

        try (InputStream is = DatabaseConfigManager.class.getClassLoader().getResourceAsStream(CONFIG_FILE)) {
            if (is != null) {
                properties.load(is);
            } else {
                throw new IOException("无法加载配置文件: " + CONFIG_FILE);
            }
        } catch (IOException e) {
            throw new RuntimeException("加载配置失败", e);
        }
    }

    private static void initializeDbConfigs() {
        // 初始化 SQL Server 配置
        Map<String, String> sqlServerConfig = new HashMap<>();
        sqlServerConfig.put("host", properties.getProperty("sqlserver.host"));
        sqlServerConfig.put("port", properties.getProperty("sqlserver.port"));
        sqlServerConfig.put("name", properties.getProperty("sqlserver.name"));
        sqlServerConfig.put("user", properties.getProperty("sqlserver.user"));
        sqlServerConfig.put("password", properties.getProperty("sqlserver.password"));
        System.out.println(properties.getProperty("sqlserver.host"));


        dbConfigs.put(DatabaseType.SQL_SERVER, sqlServerConfig);

        // 初始化 Oracle 配置
        Map<String, String> oracleConfig = new HashMap<>();
        oracleConfig.put("host", properties.getProperty("oracle.host"));
        oracleConfig.put("port", properties.getProperty("oracle.port"));
        oracleConfig.put("sid", properties.getProperty("oracle.sid"));
        oracleConfig.put("serviceName", properties.getProperty("oracle.serviceName"));
        oracleConfig.put("user", properties.getProperty("oracle.user"));
        oracleConfig.put("password", properties.getProperty("oracle.password"));
        dbConfigs.put(DatabaseType.ORACLE, oracleConfig);
    }

    public static void setActiveDatabase(DatabaseType dbType) {
        activeDbType = dbType;
        // 重新初始化工厂和连接
        DatabaseConnectionFactory.initialize(activeDbType);
        RepositoryFactory.initialize(activeDbType);
    }

    public static Map<String, String> getActiveConfig() {
        return dbConfigs.get(activeDbType);
    }

    public static DatabaseType getActiveDbType() {
        return activeDbType;
    }


}


/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1 Neo4j
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/14 - 23:04
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : DatabaseConnectionFactory.java
 * explain   : 学习  类
 **/

package infrastructure.database;

import infrastructure.common.DatabaseType;
import infrastructure.config.AppConfig;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class DatabaseConnectionFactory {

    private static DatabaseType currentDbType;

    public static void initialize(DatabaseType dbType) {
        currentDbType = dbType;
    }

    /**
     *
     * @return
     * @throws SQLException
     * @throws IOException
     */
    public static Connection getConnection() throws SQLException, IOException {
        Properties props = new Properties();

        switch (currentDbType) {
            case ORACLE:
                String oracleUrl;

                //try {
                    // 加载Oracle驱动
                    //Class.forName("oracle.jdbc.OracleDriver");
                //} catch (ClassNotFoundException e) {
                    //throw new SQLException("找不到Oracle JDBC驱动", e);
                //}

                if (AppConfig.getProperty("oracle.sid") != null) {
                    oracleUrl = String.format("jdbc:oracle:thin:@//%s:%s/%s",
                            AppConfig.getProperty("oracle.host"),
                            AppConfig.getProperty("oracle.port"),
                            AppConfig.getProperty("oracle.sid"));

                    props.setProperty("user", AppConfig.getProperty("oracle.user"));
                    props.setProperty("password", AppConfig.getProperty("oracle.password"));

                } else {
                    oracleUrl = String.format("jdbc:oracle:thin:@//%s:%s/%s",
                            AppConfig.getProperty("oracle.host"),
                            AppConfig.getProperty("oracle.port"),
                            AppConfig.getProperty("oracle.serviceName"));
                            props.setProperty("user", AppConfig.getProperty("oracle.user"));
                             props.setProperty("password", AppConfig.getProperty("oracle.password"));
                }
                return DriverManager.getConnection(oracleUrl, props);

            case SQL_SERVER:

                //try {
                    // 加载sqlserver驱动
                    //Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
               // } catch (ClassNotFoundException e) {
                   // throw new SQLException("找不到sqlserver JDBC驱动", e);
               // }

                String sqlServerUrl = String.format("jdbc:sqlserver://%s:%s;databaseName=%s",
                        AppConfig.getProperty("sqlserver.host"),
                        AppConfig.getProperty("sqlserver.port"),
                        AppConfig.getProperty("sqlserver.name"));

                String host = AppConfig.getProperty("sqlserver.host");
                String port = AppConfig.getProperty("sqlserver.port");
                String name = AppConfig.getProperty("sqlserver.name");
                String user=AppConfig.getProperty("sqlserver.user");
                String password=AppConfig.getProperty("sqlserver.password");

               // System.out.println("database host:"+host + ":" + port);
                //System.out.println("database user:"+user + ":" + password);
                props.setProperty("user", AppConfig.getProperty("sqlserver.user"));
                props.setProperty("password", AppConfig.getProperty("sqlserver.password"));

                System.out.println("database:"+sqlServerUrl);

                return DriverManager.getConnection(sqlServerUrl, user, password);

            default:
                throw new IllegalArgumentException("不支持的数据库类型");
        }
    }
}


/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1 Neo4j
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/18 - 20:09
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : OracleSchoolRepositoryImpl.java
 * explain   : 学习  类
 **/

package infrastructure.repositories.oracle;

import domain.entities.School;
import domain.entities.QueryParams;
import domain.repositories.SchoolRepository;
import infrastructure.repositories.BaseRepository;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.io.IOException;


public class OracleSchoolRepositoryImpl extends BaseRepository implements SchoolRepository {

    @Override
    public List<School> findAll(int page, int pageSize) {
        System.out.println("开始分页查询，页码: " + page + "，每页大小: " + pageSize);
        List<School> schools = new ArrayList<>();
        String sql = "SELECT * FROM School ORDER BY SchoolId " +
                "OFFSET ? ROWS FETCH NEXT ? ROWS ONLY";

        try (Connection conn = getConnection()) {
            System.out.println("成功获取数据库连接");

            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                pstmt.setInt(1, (page - 1) * pageSize);
                pstmt.setInt(2, pageSize);
                System.out.println("执行SQL: " + sql);
                System.out.println("参数1: " + (page - 1) * pageSize);
                System.out.println("参数2: " + pageSize);

                try (ResultSet rs = pstmt.executeQuery()) {
                    while (rs.next()) {
                        schools.add(mapToDomain(rs));
                    }
                    System.out.println("查询成功，返回 " + schools.size() + " 条记录");
                }
            }
        } catch (SQLException | IOException e) {
            System.err.println("数据库操作异常: " + e.getMessage());
            e.printStackTrace(); // 打印完整堆栈信息
            throw new RuntimeException("查询学校列表失败", e);
        }
        return schools;
    }

    @Override
    public int countAll() {
        String sql = "SELECT COUNT(*) FROM School";
        try (Connection conn = getConnection();
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery(sql)) {

            if (rs.next()) {
                return rs.getInt(1);
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("统计学校数量失败", e);
        }
        return 0;
    }
    @Override
    public List<School> findByParams(QueryParams params) {
        List<School> schools = new ArrayList<>();
        String sql = "SELECT * FROM (" +
                "  SELECT s.*, ROW_NUMBER() OVER (ORDER BY SchoolId) rn " +
                "  FROM School s " +
                "  WHERE 1=1 ";

        if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
            sql += "AND (SchoolId LIKE ? OR SchoolName LIKE ?) ";
        }

        sql += ") WHERE rn BETWEEN ? AND ?";

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            conn = getConnection();
            pstmt = conn.prepareStatement(sql);

            int paramIndex = 1;
            if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
                String searchTerm = "%" + params.getSearchTerm() + "%";
                pstmt.setString(paramIndex++, searchTerm);
                pstmt.setString(paramIndex++, searchTerm);
            }

            int startRow = (params.getPageNumber() - 1) * params.getPageSize() + 1;
            int endRow = params.getPageNumber() * params.getPageSize();

            pstmt.setInt(paramIndex++, startRow);
            pstmt.setInt(paramIndex, endRow);

            rs = pstmt.executeQuery();
            while (rs.next()) {
                schools.add(mapToDomain(rs));
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("按条件查询学校失败", e);
        } finally {
            closeResources(conn, pstmt, rs);
        }

        return schools;
    }
    @Override
    public int countByParams(QueryParams params) {
        StringBuilder sql = new StringBuilder("SELECT COUNT(*) FROM School WHERE 1=1 ");

        // 构建查询条件
        if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
            sql.append("AND (SchoolId LIKE ? OR SchoolName LIKE ?)");
        }

        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql.toString())) {

            int paramIndex = 1;
            // 设置查询参数
            if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
                String searchTerm = "%" + params.getSearchTerm() + "%";
                pstmt.setString(paramIndex++, searchTerm);
                pstmt.setString(paramIndex, searchTerm);
            }

            try (ResultSet rs = pstmt.executeQuery()) {
                if (rs.next()) {
                    return rs.getInt(1);
                }
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("统计符合条件的学校数量失败", e);
        }
        return 0;
    }
    @Override
    public School findById(String schoolId) {
        String sql = "SELECT * FROM School WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, schoolId);
            try (ResultSet rs = pstmt.executeQuery()) {
                if (rs.next()) {
                    return mapToDomain(rs);
                }
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("查找学校失败", e);
        }
        return null;
    }

    @Override
    public void save(School school) {
        // 检查是插入还是更新
        if (findById(school.getSchoolId()) == null) {
            insertSchool(school);
        } else {
            updateSchool(school);
        }
    }

    private void insertSchool(School school) {
        String sql = "INSERT INTO School (SchoolId, SchoolName, SchoolTelNo) VALUES (?, ?, ?)";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, school.getSchoolId());
            pstmt.setString(2, school.getSchoolName());
            pstmt.setString(3, school.getSchoolTelNo());

            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("添加学校失败", e);
        }
    }

    private void updateSchool(School school) {
        String sql = "UPDATE School SET SchoolName = ?, SchoolTelNo = ? WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, school.getSchoolName());
            pstmt.setString(2, school.getSchoolTelNo());
            pstmt.setString(3, school.getSchoolId());

            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("更新学校失败", e);
        }
    }

    @Override
    public void delete(String schoolId) {
        String sql = "DELETE FROM School WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, schoolId);
            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("删除学校失败", e);
        }
    }
    private School mapToDomain(ResultSet rs) throws SQLException {
        return new School(
                rs.getString("SchoolId"),
                rs.getString("SchoolName"),
                rs.getString("SchoolTelNo")
        );
    }



}



/**
 * encoding: utf-8
 * 版权所有 2025 ©涂聚文有限公司 ®
 * 许可信息查看：言語成了邀功盡責的功臣，還需要行爲每日來值班嗎
 * 描述：
 * Author    : geovindu,Geovin Du 涂聚文.
 * IDE       : IntelliJ IDEA 2024.3.6 Java 17
 * # database  : Oracle21c,MySQL 9.0,SQL Server 2019,PostgreSQL 17.1 Neo4j
 * # OS        : window10
 * Datetime  : 2025 - 2025/7/18 - 19:57
 * User      : geovindu
 * Product   : IntelliJ IDEA
 * Project   : DDDdemo
 * File      : SqlServerSchoolRepositoryImpl.java
 * explain   : 学习  类
 **/

package infrastructure.repositories.sqlserver;

import domain.entities.School;
import domain.entities.QueryParams;
import domain.repositories.SchoolRepository;
import infrastructure.repositories.BaseRepository;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.io.IOException;


public class SqlServerSchoolRepositoryImpl extends BaseRepository implements SchoolRepository {


    @Override
    public List<School> findAll(int page, int pageSize) {
        List<School> schools = new ArrayList<>();
        // SQL Server 2012+ 分页语法
        String sql = "SELECT * FROM School " +
                "ORDER BY SchoolId " +
                "OFFSET ? ROWS FETCH NEXT ? ROWS ONLY";

        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setInt(1, (page - 1) * pageSize);
            pstmt.setInt(2, pageSize);

            try (ResultSet rs = pstmt.executeQuery()) {
                while (rs.next()) {
                    schools.add(mapToDomain(rs));
                }
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("查询学校列表失败", e);
        }
        return schools;
    }

    @Override
    public int countAll() {
        String sql = "SELECT COUNT(*) FROM School";
        try (Connection conn = getConnection();
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery(sql)) {

            if (rs.next()) {
                return rs.getInt(1);
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("统计学校数量失败", e);
        }
        return 0;
    }
    @Override
    public List<School> findByParams(QueryParams params) {
        List<School> schools = new ArrayList<>();
        StringBuilder sql = new StringBuilder(
                "SELECT * FROM School WHERE 1=1 "
        );

        if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
            sql.append("AND (SchoolId LIKE ? OR SchoolName LIKE ?) ");
        }

        sql.append("ORDER BY SchoolId OFFSET ? ROWS FETCH NEXT ? ROWS ONLY");

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            conn = getConnection();
            pstmt = conn.prepareStatement(sql.toString());

            int paramIndex = 1;
            if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
                String searchTerm = "%" + params.getSearchTerm() + "%";
                pstmt.setString(paramIndex++, searchTerm);
                pstmt.setString(paramIndex++, searchTerm);
            }

            pstmt.setInt(paramIndex++, (params.getPageNumber() - 1) * params.getPageSize());
            pstmt.setInt(paramIndex, params.getPageSize());

            rs = pstmt.executeQuery();
            while (rs.next()) {
                schools.add(mapToDomain(rs));
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("按条件查询学校失败", e);
        } finally {
            closeResources(conn, pstmt, rs);
        }

        return schools;
    }

    @Override
    public int countByParams(QueryParams params) {
        StringBuilder sql = new StringBuilder("SELECT COUNT(*) FROM School WHERE 1=1 ");

        // 构建查询条件
        if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
            sql.append("AND (SchoolId LIKE ? OR SchoolName LIKE ?)");
        }

        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql.toString())) {

            int paramIndex = 1;
            // 设置查询参数
            if (params.getSearchTerm() != null && !params.getSearchTerm().isEmpty()) {
                String searchTerm = "%" + params.getSearchTerm() + "%";
                pstmt.setString(paramIndex++, searchTerm);
                pstmt.setString(paramIndex, searchTerm);
            }

            try (ResultSet rs = pstmt.executeQuery()) {
                if (rs.next()) {
                    return rs.getInt(1);
                }
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("统计符合条件的学校数量失败", e);
        }
        return 0;
    }

    @Override
    public School findById(String schoolId) {
        String sql = "SELECT * FROM School WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, schoolId);
            try (ResultSet rs = pstmt.executeQuery()) {
                if (rs.next()) {
                    return mapToDomain(rs);
                }
            }
        } catch (SQLException | IOException e) {
            throw new RuntimeException("查找学校失败", e);
        }
        return null;
    }

    @Override
    public void save(School school) {
        // 检查是插入还是更新
        if (findById(school.getSchoolId()) == null) {
            insertSchool(school);
        } else {
            updateSchool(school);
        }
    }
    private void insertSchool(School school) {
        String sql = "INSERT INTO School (SchoolId, SchoolName, SchoolTelNo) VALUES (?, ?, ?)";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, school.getSchoolId());
            pstmt.setString(2, school.getSchoolName());
            pstmt.setString(3, school.getSchoolTelNo());

            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("添加学校失败", e);
        }
    }

    private void updateSchool(School school) {
        String sql = "UPDATE School SET SchoolName = ?, SchoolTelNo = ? WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, school.getSchoolName());
            pstmt.setString(2, school.getSchoolTelNo());
            pstmt.setString(3, school.getSchoolId());

            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("更新学校失败", e);
        }
    }

    @Override
    public void delete(String schoolId) {
        String sql = "DELETE FROM School WHERE SchoolId = ?";
        try (Connection conn = getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            pstmt.setString(1, schoolId);
            pstmt.executeUpdate();
        } catch (SQLException | IOException e) {
            throw new RuntimeException("删除学校失败", e);
        }
    }
    private School mapToDomain(ResultSet rs) throws SQLException {
        return new School(
                rs.getString("SchoolId"),
                rs.getString("SchoolName"),
                rs.getString("SchoolTelNo")
        );
    }

}