Flink之redis sink

1. Import dependencies

<!-- https://mvnrepository.com/artifact/org.apache.bahir/flink-connector-redis -->
<dependency>
    <groupId>org.apache.bahir</groupId>
    <artifactId>flink-connector-redis_2.11</artifactId>
    <version>1.0</version>
</dependency>

2. Customize the RedisMapper class

Example: Write the IDs of all User sample objects in Datream into the set whose key is Online_Number

class MyRedisMapper extends RedisMapper[User]{

//定义对于每条数据使用的redis命令与描述
  override def getCommandDescription: RedisCommandDescription = {
    new RedisCommandDescription(RedisCommand.SADD , "Online_Number")
  }
  
//定义每条数据的key值
    override def getKeyFromData(user: User): String = "Online_Number"
//定义每条数据的value值
    override def getValueFromData(user: User): String = user.id.toString
}

3. Create redis configuration object

Redis sink provides three types of config classes, namely FlinkJedisPoolConfig, FlinkJedisClusterConfig, and FlinkJedisSentinelConfig.

FlinkJedisPoolConfig : a single-node redis instance.

FlinkJedisPoolConfig : Redis instance in cluster mode.

FlinkJedisSentinelConfig : Redis instance with sentinel mode.

Take FlinkJedisPoolConfig as an example:

 val config: FlinkJedisPoolConfig = FlinkJedisPoolConfig.Builder().setHost("localhost").setPort(6379).build()

4. Create RedisSink object

Create a RedisSink object, the parameters are the config created in the third step and the RedisMapper object defined in the second step .

val redisSink = new RedisSink[User](config,new MyRedisMapper)

5. Call addSink of Dstream

dataStream.addSink(redisSink)