闪烁CEP未打印结果

Question

我正在尝试打印一个字符串，如果使用Flink CEP库找到Hello和world。我的来源是Kafka，并使用控制台生产者输入数据。这一部分正在发挥作用。我可以打印出我在主题中输入的内容。但是，它不会打印出我的最后一条消息“世界真好！”。它甚至不会打印出它进入了lambda。下面是类

package kafka;

import org.apache.flink.cep.CEP;
import org.apache.flink.cep.PatternStream;
import org.apache.flink.cep.pattern.Pattern;
import org.apache.flink.streaming.api.TimeCharacteristic;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer08;
import org.apache.flink.streaming.util.serialization.SimpleStringSchema;
import org.apache.flink.util.Collector;

import java.util.Map;
import java.util.Properties;

/**
 * Created by crackerman on 9/16/16.
*/
public class WordCount {

public static void main(String[] args) throws Exception {

    Properties properties = new Properties();
    properties.put("bootstrap.servers", "localhost:9092");
    properties.put("zookeeper.connect", "localhost:2181");
    properties.put("group.id", "test");
    StreamExecutionEnvironment see = StreamExecutionEnvironment.getExecutionEnvironment();
    see.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

    DataStream<String> src = see.addSource(new FlinkKafkaConsumer08<>("complexString",
                                                                      new SimpleStringSchema(),
                                                                      properties));

    src.print();


    Pattern<String, String> pattern = Pattern.<String>begin("first")
            .where(evt -> evt.contains("Hello"))
            .followedBy("second")
            .where(evt -> evt.contains("World"));

    PatternStream<String> patternStream = CEP.pattern(src, pattern);

    DataStream<String> alerts = patternStream.flatSelect(
            (Map<String, String> in, Collector<String> out) -> {
                System.out.println("Made it to the lambda");
                String first = in.get("first");
                String second = in.get("second");
                System.out.println("First: " + first);
                System.out.println("Second: " + second);

                if (first.equals("Hello") && second.equals("World")) {

                    out.collect("The world is so nice!");
                }


            });

    alerts.print();

    see.execute();
}

}

任何帮助都将不胜感激。

谢谢!

Answer 1

问题是下面这行

 see.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

如果去掉它，它就会按照我预期的方式工作。