<dependency>
    <groupId>org.apache.flink</groupId>
    <artifactId>flink-connector-redis_2.10</artifactId>
    <version>1.1.5</version>
</dependency>

然后我们实现一个自己的RedisSinkExample：

//指定Redis set
public static final class RedisSinkExample implements RedisMapper<Tuple2<String,Integer>> {
public RedisCommandDescription getCommandDescription() {
    return new RedisCommandDescription(RedisCommand.SET, null);
}

public String getKeyFromData(Tuple2<String, Integer> data) {
    return data.f0;
}

public String getValueFromData(Tuple2<String, Integer> data) {
    return data.f1.toString();
}
}

我们用最简单的单机Redis的SET命令进行演示。

完整的代码如下，实现一个读取Kafka的消息，然后进行WordCount，并把结果更新到redis中：

public class RedisSinkTest {

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

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
env.enableCheckpointing(2000);
env.getCheckpointConfig().setCheckpointingMode(CheckpointingMode.EXACTLY_ONCE);

//连接kafka
Properties properties = new Properties();
properties.setProperty("bootstrap.servers", "127.0.0.1:9092");

FlinkKafkaConsumer<String> consumer = new FlinkKafkaConsumer<>("test", new SimpleStringSchema(), properties);
consumer.setStartFromEarliest();
DataStream<String> stream = env.addSource(consumer);
DataStream<Tuple2<String, Integer>> counts = stream.flatMap(new LineSplitter()).keyBy(0).sum(1);

//实例化FlinkJedisPoolConfig 配置redis
FlinkJedisPoolConfig conf = new FlinkJedisPoolConfig.Builder().setHost("127.0.0.1").setHost("6379").build();
//实例化RedisSink，并通过flink的addSink的方式将flink计算的结果插入到redis

counts.addSink(new RedisSink<>(conf,new RedisSinkExample()));
env.execute("WordCount From Kafka To Redis");

}//
public static final class LineSplitter implements FlatMapFunction<String, Tuple2<String, Integer>> {

@Override
public void flatMap(String value, Collector<Tuple2<String, Integer>> out) {
    String[] tokens = value.toLowerCase().split("\\W+");
    for (String token : tokens) {
        if (token.length() > 0) {
            out.collect(new Tuple2<String, Integer>(token, 1));
        }
    }
}
}
//指定Redis set
public static final class RedisSinkExample implements RedisMapper<Tuple2<String,Integer>> {
public RedisCommandDescription getCommandDescription() {
    return new RedisCommandDescription(RedisCommand.SET, null);
}

public String getKeyFromData(Tuple2<String, Integer> data) {
    return data.f0;
}

public String getValueFromData(Tuple2<String, Integer> data) {
    return data.f1.toString();
}
}

}//

预告，后续更新写入Hbase和Mysql案例代码。

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原始发表：2019-03-07，如有侵权请联系 cloudcommunity@tencent.com 删除

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