クラウドスターデータ---Apache Flink実戦シリーズ(逸品版):Flinkストリーム処理API詳細とプログラミング実戦010-DataStreamとMySqlカスタムsinkとsource(Java版)002

三、カスタムソース
1.カスタムソース

package code.book.stream.customsinkandsource.jdbc.java;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.functions.source.RichSourceFunction;

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


public class StudentSourceFromMysql extends RichSourceFunction<Student> {
    PreparedStatement ps;
    private Connection connection;

    /**
     *  、open()       ，      invoke              。
     */
    @Override
    public void open(Configuration parameters) throws Exception {
        super.open(parameters);
        String driver = "com.mysql.jdbc.Driver";
        String url = "jdbc:mysql://qingcheng11:3306/flinktest";
        String username = "root";
        String password = "qingcheng";
        //1.    
        Class.forName(driver);
        //2.    
        connection = DriverManager.getConnection(url, username, password);
        //3.      
        String sql = "select stuid,stuname,stuaddr,stusex from Student;";
        ps = connection.prepareStatement(sql);
    }

    /**
     *  、DataStream    run()        
     */
    @Override
    public void run(SourceContext sourceContext) throws Exception {
        try {
            //4.    ，    
            ResultSet resultSet = ps.executeQuery();
            while (resultSet.next()) {
                Student student = new Student(
                resultSet.getInt("stuid"),
                resultSet.getString("stuname").trim(),
                resultSet.getString("stuaddr").trim(), 
                resultSet.getString("stusex").trim());
                sourceContext.collect(student);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void cancel() {

    }

    /**
     *  、            ，             
     */
    @Override
    public void close() throws Exception {
        //5.         
        super.close();
        if (connection != null) {
            connection.close();
        }
        if (ps != null) {
            ps.close();
        }
    }
}

2.sourceテストプログラム

package code.book.stream.customsinkandsource.jdbc.java;

import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class StudentSourceFromMysqlTest {
    public static void main(String[] args) throws Exception {
        //1.       
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        //2.    source     
        DataStream students=env.addSource(new StudentSourceFromMysql());

        //3.    
        students.print();

        //4.     
        env.execute();
    }
}

3.sourceテスト効果

       mysql    。