Java写一个每晚12点定时备份达梦数据库数据的代码

在Java中，你可以使用`java.util.Timer`或更现代的`java.time`和`ScheduledExecutorService`来创建一个定时任务，结合JDBC（Java Database Connectivity）来执行数据库备份。以下是一个基本的示例，使用`ScheduledExecutorService`，因为它提供了更多的灵活性和控制。

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;

import javax.sql.DataSource;

public class BackupTask implements Runnable {
    private static final String BACKUP_QUERY = "INSERT INTO backup_table SELECT * FROM main_table";
    private DataSource dataSource;

    public BackupTask(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    @Override
    public void run() {
        try {
            // 获取当前时间并转换为指定时区（例如UTC）
            LocalDateTime currentDateTime = LocalDateTime.now().atZone(ZoneId.of("UTC"));
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd_HH-mm");
            String backupFileName = "backup_" + currentDateTime.format(formatter) + ".sql";

            // 连接到数据库
            Connection conn = dataSource.getConnection();
            PreparedStatement stmt = conn.prepareStatement(BACKUP_QUERY);

            // 执行备份查询
            stmt.executeUpdate();

            // 关闭连接
            stmt.close();
            conn.close();

            System.out.println("Backup completed for time: " + backupFileName);
        } catch (SQLException e) {
            System.err.println("Error during backup: " + e.getMessage());
        }
    }

    public static void main(String[] args) {
        // 创建一个基于文件系统的数据源
        // 注意替换实际的URL、用户名和密码
        String url = "jdbc:dmdb://localhost:1521/mydatabase";
        String username = "your_username";
        String password = "your_password";
        try {
            DataSource dataSource = DriverManager.getConnection(url, username, password)..unwrap(DataSource.class);
            
            // 使用ScheduledExecutorService来调度任务每晚12点执行
            ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
            executor.scheduleAtFixedRate(new BackupTask(dataSource), 0, 1, TimeUnit.DAYS); // 每天午夜12点执行

            executor.shutdown(); // 不关闭，否则会在第一次执行后立即停止
            System.out.println("Backup task scheduled. Press Ctrl+C to stop.");
        } catch (SQLException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}