Spring Boot JPA中利用数据引导机制按需创建数据库视图

// AbstractDataLoader.java
public abstract class AbstractDataLoader {
    /**
     * 加载特定环境的数据或创建数据库视图。
     */
    public abstract void loadEnvironmentSpecificData();
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Profile;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;

// ProductionDataLoader.java
@Component // 注册为Spring组件
@Profile("prod") // 仅当Spring Profile为"prod"时激活
public class ProductionDataLoader extends AbstractDataLoader {

    private final JdbcTemplate jdbcTemplate; // 用于执行原生SQL

    @Autowired
    public ProductionDataLoader(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    @Override
    public void loadEnvironmentSpecificData() {
        System.out.println("生产环境数据加载器：开始创建数据库视图...");
        // 示例：创建或替换一个用于产品汇总的视图
        String createProductSummaryViewSql = "CREATE OR REPLACE VIEW product_summary_view AS " +
                                             "SELECT p.id AS product_id, p.name AS product_name, p.price, " +
                                             "       COUNT(oi.id) AS total_order_items " +
                                             "FROM products p " +
                                             "LEFT JOIN order_items oi ON p.id = oi.product_id " +
                                             "GROUP BY p.id, p.name, p.price;";
        try {
            jdbcTemplate.execute(createProductSummaryViewSql);
            System.out.println("视图 'product_summary_view' 创建成功。");
        } catch (Exception e) {
            System.err.println("创建视图 'product_summary_view' 失败：" + e.getMessage());
            // 生产环境中应记录更详细的日志或抛出特定异常
        }

        // 其他生产环境特定的数据初始化或视图创建逻辑...
    }
}

// DevelopmentDataLoader.java (可选)
@Component
@Profile("dev") // 仅当Spring Profile为"dev"时激活
public class DevelopmentDataLoader extends AbstractDataLoader {

    // 可以注入Repository来加载测试数据
    // private final UserRepository userRepository;

    // @Autowired
    // public DevelopmentDataLoader(UserRepository userRepository) {
    //     this.userRepository = userRepository;
    // }

    @Override
    public void loadEnvironmentSpecificData() {
        System.out.println("开发环境数据加载器：初始化开发环境数据...");
        // 可以在这里加载测试数据，或者创建一些开发环境特有的视图
        // userRepository.save(new User("testuser", "password"));
    }
}

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import org.springframework.beans.factory.annotation.Autowired;

// DataLoaderApplicationRunner.java
@Component
public class DataLoaderApplicationRunner implements ApplicationRunner {

    // Spring会自动注入当前激活的AbstractDataLoader实例
    private final AbstractDataLoader activeDataLoader;

    @Autowired
    public DataLoaderApplicationRunner(AbstractDataLoader activeDataLoader) {
        this.activeDataLoader = activeDataLoader;
    }

    @Override
    public void run(ApplicationArguments args) throws Exception {
        // 在应用启动后执行数据加载逻辑
        activeDataLoader.loadEnvironmentSpecificData();
    }
}