本章节次要演示从 socket 接收数据，通过滚动窗口每 30 秒运算一次窗口数据，而后将后果写入 Mysql 数据库
（1）筹备一个实体对象，音讯对象
package com.pojo;
import java.io.Serializable;
/**
- Created by lj on 2022-07-05.
*/
public class WaterSensor implements Serializable {
private String id;
private long ts;
private int vc;
public WaterSensor(){}
public WaterSensor(String id,long ts,int vc){
this.id = id;
this.ts = ts;
this.vc = vc;
}
public int getVc() {return vc;}
public void setVc(int vc) {this.vc = vc;}
public String getId() {return id;}
public void setId(String id) {this.id = id;}
public long getTs() {return ts;}
public void setTs(long ts) {this.ts = ts;}}
（2）编写 socket 代码，模仿数据发送
package com.producers;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Random;
/**
- Created by lj on 2022-07-05.
*/
public class Socket_Producer {
public static void main(String[] args) throws IOException {
try {ServerSocket ss = new ServerSocket(9999);
System.out.println("启动 server ....");
Socket s = ss.accept();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
String response = "java,1,2";
// 每 2s 发送一次音讯
int i = 0;
Random r=new Random();
String[] lang = {"flink","spark","hadoop","hive","hbase","impala","presto","superset","nbi"};
while(true){Thread.sleep(2000);
response= lang[r.nextInt(lang.length)] + "," + i + "," + i+"\n";
System.out.println(response);
try{bw.write(response);
bw.flush();
i++;
}catch (Exception ex){System.out.println(ex.getMessage());
}
}
} catch (IOException | InterruptedException e) {e.printStackTrace();
}
}}
（3）从 socket 端接收数据，并设置 30 秒触发执行一次窗口运算
package com.examples;
import com.pojo.WaterSensor;
import com.sinks.RetractStream_Mysql;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.types.Row;
import static org.apache.flink.table.api.Expressions.$;
/**
- Created by lj on 2022-07-06.
*/
public class Flink_Group_Window_Tumble_Sink_Mysql {
public static void main(String[] args) throws Exception {StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);
DataStreamSource<String> streamSource = env.socketTextStream("127.0.0.1", 9999,"\n");
SingleOutputStreamOperator<WaterSensor> waterDS = streamSource.map(new MapFunction<String, WaterSensor>() {
@Override
public WaterSensor map(String s) throws Exception {String[] split = s.split(",");
return new WaterSensor(split[0], Long.parseLong(split[1]), Integer.parseInt(split[2]));
}
});
// 将流转化为表
Table table = tableEnv.fromDataStream(waterDS,
$("id"),
$("ts"),
$("vc"),
$("pt").proctime());
tableEnv.createTemporaryView("EventTable", table);
Table result = tableEnv.sqlQuery(
"SELECT" +
"id," + //window_start, window_end,
"COUNT(ts) ,SUM(ts)" +
"FROM TABLE(" +
"TUMBLE( TABLE EventTable ," +
"DESCRIPTOR(pt)," +
"INTERVAL'30'SECOND))" +
"GROUP BY id , window_start, window_end"
);
tableEnv.toRetractStream(result, Row.class).addSink(new RetractStream_Mysql());
env.execute();}}
（4）定义一个写入到 mysql 的 sink
package com.sinks;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.functions.sink.RichSinkFunction;
import org.apache.flink.types.Row;
/**
- Created by lj on 2022-07-06.
*/
public class RetractStream_Mysql extends RichSinkFunction<Tuple2<Boolean, Row>> {
private static final long serialVersionUID = -4443175430371919407L;
PreparedStatement ps;
private Connection connection;
/**
* open() 办法中建设连贯，这样不必每次 invoke 的时候都要建设连贯和开释连贯
*
* @param parameters
* @throws Exception
*/
@Override
public void open(Configuration parameters) throws Exception {super.open(parameters);
connection = getConnection();}
@Override
public void close() throws Exception {super.close();
// 敞开连贯和开释资源
if (connection != null) {connection.close();
}
if (ps != null) {ps.close();
}
}
/**
* 每条数据的插入都要调用一次 invoke() 办法
*
* @param context
* @throws Exception
*/
@Override
public void invoke(Tuple2<Boolean, Row> userPvEntity, Context context) throws Exception {String sql = "INSERT INTO flinkcomponent(componentname,componentcount,componentsum) VALUES(?,?,?);";
ps = this.connection.prepareStatement(sql);
ps.setString(1,userPvEntity.f1.getField(0).toString());
ps.setInt(2, Integer.parseInt(userPvEntity.f1.getField(1).toString()));
ps.setInt(3, Integer.parseInt(userPvEntity.f1.getField(2).toString()));
ps.executeUpdate();}
private static Connection getConnection() {
Connection con = null;
try {Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=UTF-8&useSSL=false","root","root");
} catch (Exception e) {System.out.println("-----------mysql get connection has exception , msg ="+ e.getMessage());
}
return con;
}}
（5）成果演示，每 30 秒往数据库写一次数据