是否可以在Flink应用程序中访问FlatMapFunction中的数据库？

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;

import java.sql.*;

public class DatabaseAccessExample {

    public static void main(String[] args) throws Exception {
        // 创建执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 配置数据库连接信息
        String dbUrl = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        // 创建JDBC连接器
        JdbcConnectionOptions connectionOptions = new JdbcConnectionOptions.JdbcConnectionOptionsBuilder()
                .withUrl(dbUrl)
                .withUsername(username)
                .withPassword(password)
                .build();

        // 创建输入流
        DataStream<String> input = env.fromElements("data1", "data2", "data3");

        // 应用FlatMapFunction并访问数据库
        DataStream<Tuple2<String, Integer>> result = input.flatMap(new DatabaseFlatMapFunction(connectionOptions));

        // 打印结果
        result.print();

        // 执行程序
        env.execute("Database Access Example");
    }

    public static class DatabaseFlatMapFunction implements FlatMapFunction<String, Tuple2<String, Integer>> {
        private final JdbcConnectionOptions connectionOptions;

        public DatabaseFlatMapFunction(JdbcConnectionOptions connectionOptions) {
            this.connectionOptions = connectionOptions;
        }

        @Override
        public void flatMap(String input, Collector<Tuple2<String, Integer>> collector) throws Exception {
            // 创建数据库连接
            try (Connection connection = DriverManager.getConnection(connectionOptions.getUrl(),
                    connectionOptions.getUsername(), connectionOptions.getPassword())) {
                // 执行SQL查询
                try (Statement statement = connection.createStatement()) {
                    ResultSet resultSet = statement.executeQuery("SELECT COUNT(*) FROM mytable");
                    if (resultSet.next()) {
                        int count = resultSet.getInt(1);
                        collector.collect(new Tuple2<>(input, count));
                    }
                }
            }
        }
    }
}