Redis
API
通过flink 操作redis 其实我们可以通过传统的redis 连接池Jpoools 进行redis 的相关操作，但是flink 提供了专门操作redis 的RedisSink，使用起来更方便，而且不用我们考虑性能的问题，接下来将主要介绍RedisSink 如何使用。
Apache Flink Streaming Connector for Redis
RedisSink 核心类是RedisMapper 是一个接口，使用时我们要编写自己的redis 操作类实现这个接口中的三个方法，如下所示
1.getCommandDescription() ：
设置使用的redis 数据结构类型，和key 的名称，通过RedisCommand 设置数据结构类型
2.String getKeyFromData(T data)：
设置value 中的键值对key的值
3.String getValueFromData(T data);
设置value 中的键值对value的值
使用RedisCommand设置数据结构类型时和redis结构对应关系
Data Type | Redis Command [Sink] |
|---|---|
HASH | HSET |
LIST | RPUSH, LPUSH |
SET | SADD |
PUBSUB | PUBLISH |
STRING | SET |
HYPER_LOG_LOG | PFADD |
SORTED_SET | ZADD |
SORTED_SET | ZREM |
需求
将Flink集合中的数据通过自定义Sink保存到Redis
代码实现
代码语言：javascript复制package cn.it.connectors;
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.tuple.Tuple;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.redis.RedisSink;
import org.apache.flink.streaming.connectors.redis.common.config.FlinkJedisPoolConfig;
import org.apache.flink.streaming.connectors.redis.common.mapper.RedisCommand;
import org.apache.flink.streaming.connectors.redis.common.mapper.RedisCommandDescription;
import org.apache.flink.streaming.connectors.redis.common.mapper.RedisMapper;
import org.apache.flink.util.Collector;
/**
* Author lanson
* Desc
* 需求:
* 接收消息并做WordCount,
* 最后将结果保存到Redis
* 注意:存储到Redis的数据结构:使用hash也就是map
* key value
* WordCount (单词,数量)
*/
public class ConnectorsDemo_Redis {
public static void main(String[] args) throws Exception {
//1.env
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
//2.Source
DataStream<String> linesDS = env.socketTextStream("node1", 9999);
//3.Transformation
//3.1切割并记为1
SingleOutputStreamOperator<Tuple2<String, Integer>> wordAndOneDS = linesDS.flatMap(new FlatMapFunction<String, Tuple2<String, Integer>>() {
@Override
public void flatMap(String value, Collector<Tuple2<String, Integer>> out) throws Exception {
String[] words = value.split(" ");
for (String word : words) {
out.collect(Tuple2.of(word, 1));
}
}
});
//3.2分组
KeyedStream<Tuple2<String, Integer>, Tuple> groupedDS = wordAndOneDS.keyBy(0);
//3.3聚合
SingleOutputStreamOperator<Tuple2<String, Integer>> result = groupedDS.sum(1);
//4.Sink
result.print();
// * 最后将结果保存到Redis
// * 注意:存储到Redis的数据结构:使用hash也就是map
// * key value
// * WordCount (单词,数量)
//-1.创建RedisSink之前需要创建RedisConfig
//连接单机版Redis
FlinkJedisPoolConfig conf = new FlinkJedisPoolConfig.Builder().setHost("127.0.0.1").build();
//连接集群版Redis
//HashSet<InetSocketAddress> nodes = new HashSet<>(Arrays.asList(new InetSocketAddress(InetAddress.getByName("node1"), 6379),new InetSocketAddress(InetAddress.getByName("node2"), 6379),new InetSocketAddress(InetAddress.getByName("node3"), 6379)));
//FlinkJedisClusterConfig conf2 = new FlinkJedisClusterConfig.Builder().setNodes(nodes).build();
//连接哨兵版Redis
//Set<String> sentinels = new HashSet<>(Arrays.asList("node1:26379", "node2:26379", "node3:26379"));
//FlinkJedisSentinelConfig conf3 = new FlinkJedisSentinelConfig.Builder().setMasterName("mymaster").setSentinels(sentinels).build();
//-3.创建并使用RedisSink
result.addSink(new RedisSink<Tuple2<String, Integer>>(conf, new RedisWordCountMapper()));
//5.execute
env.execute();
}
/**
* -2.定义一个Mapper用来指定存储到Redis中的数据结构
*/
public static class RedisWordCountMapper implements RedisMapper<Tuple2<String, Integer>> {
@Override
public RedisCommandDescription getCommandDescription() {
return new RedisCommandDescription(RedisCommand.HSET, "WordCount");
}
@Override
public String getKeyFromData(Tuple2<String, Integer> data) {
return data.f0;
}
@Override
public String getValueFromData(Tuple2<String, Integer> data) {
return data.f1.toString();
}
}
}
