kfaka storm写入mysql

import org.apache.storm.topology.BasicOutputCollector;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.base.BaseBasicBolt;
import org.apache.storm.tuple.Tuple;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

public class MySQLBolt extends BaseBasicBolt {
    private Connection connection;
    private PreparedStatement preparedStatement;

    @Override
    public void prepare(Map stormConf, TopologyContext context) {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
            preparedStatement = connection.prepareStatement("INSERT INTO mytable (field1, field2) VALUES (?, ?)");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void execute(Tuple input, BasicOutputCollector collector) {
        String field1 = input.getStringByField("field1");
        String field2 = input.getStringByField("field2");
        try {
            preparedStatement.setString(1, field1);
            preparedStatement.setString(2, field2);
            preparedStatement.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        // 不需要输出字段
    }

    @Override
    public void cleanup() {
        try {
            if (preparedStatement != null) {
                preparedStatement.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}