flink使用kafka为数据源

<flink.version>1.10.2</flink.version>

<dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.flink/flink-streaming-java -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_2.12</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka_2.12</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
            <scope>runtime</scope>
        </dependency>

1.增加flink依赖

2.代码实现

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.shaded.guava18.com.google.common.base.Strings;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;

import java.util.Properties;

public class KafkaExample {
    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers", "192.168.1.85:9092,192.168.1.86:9092,192.168.1.87:9092");
        properties.setProperty("group.id", "g2");
        DeserializationSchema<String> deserializationSchema = new SimpleStringSchema();
        String topic = "customer_statusChangedEvent";
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        DataStream<String> text = env.addSource(
                new FlinkKafkaConsumer<String>(topic, deserializationSchema, properties));

        DataStream<Tuple2<String, Integer>> dataStream = text
                .filter(p -> !Strings.isNullOrEmpty(p))
                .map(new MapFunction<String, Tuple2<String, Integer>>() {
                    @Override
                    public Tuple2<String, Integer> map(String p) throws Exception {
                        CustomerStatusChangedEvent event = JsonHelper.fromJson(p, CustomerStatusChangedEvent.class);
                        return new Tuple2<String, Integer>(Long.toString(event.getCustomerId()),

                                event.getNewStatus());
                    }
                });

        dataStream.print();
        try {
            env.execute("Flink-Kafka");
        } catch (Exception ex) {

        }
    }
}

public  class CustomerStatusChangedEvent {
    private Long customerId;
    @JsonProperty("nStatus")
    private Integer newStatus;
    @JsonProperty("oStatus")
    private Integer oldStatus;

    public Long getCustomerId() {
        return customerId;
    }

    public void setCustomerId(Long customerId) {
        this.customerId = customerId;
    }

    public Integer getNewStatus() {
        return newStatus;
    }

    public void setNewStatus(Integer newStatus) {
        this.newStatus = newStatus;
    }

    public Integer getOldStatus() {
        return oldStatus;
    }

    public void setOldStatus(Integer oldStatus) {
        this.oldStatus = oldStatus;
    }
}

4.输出

当kafka的对应的topic有数据产生时, 将输出 类似下面数据

(5010,1)