验证本文需要具备Docker及Docker-composer，作者使用的环境为Mac Docker
Docker启动Flink集群
首先下载Flink的镜像docker pull flink，我下载的是1.9.0版本。
然后编写 docker-composer.yml
代码语言：javascript复制version: "2.1"
services:
jobmanager:
image: flink
expose:
- "6123"
ports:
- "8081:8081"
command: jobmanager
environment:
- JOB_MANAGER_RPC_ADDRESS=jobmanager
taskmanager:
image: flink
expose:
- "6121"
- "6122"
depends_on:
- jobmanager
command: taskmanager
links:
- "jobmanager:jobmanager"
environment:
- JOB_MANAGER_RPC_ADDRESS=jobmanager示例代码
本代码完成的功能是从SOCKET端口中读取文本信息，分词后在统计周期内计算每个单词出现的次数。这里只是列出关键代码，全部工程代码可以参考我的Github
代码语言：javascript复制public class SocketWindowWordCount {
public static void main(String[] args) throws Exception {
final int port;
final String host;
port = 9008;
host = "192.168.65.2";
final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
DataStream<String> text = env.socketTextStream(host, port, "n");
DataStream<WordWithCount> windowCounts = text
.flatMap(new FlatMapFunction<String, WordWithCount>(){
@Override
public void flatMap(String value, Collector<WordWithCount> out){
for(String word : value.split("\s")){
out.collect(new WordWithCount(word, 1L));
}
}
})
.keyBy("word")
.timeWindow(Time.seconds(5), Time.seconds(1))
.reduce(new ReduceFunction<WordWithCount>(){
@Override
public WordWithCount reduce(WordWithCount a, WordWithCount b){
return new WordWithCount(a.word, a.count b.count);
}
});
windowCounts.print().setParallelism(1);
env.execute("Socket Window WordCount");
}
public static class WordWithCount {
public String word;
public long count;
public WordWithCount(){}
public WordWithCount(String word, long count){
this.word = word;
this.count = count;
}
@Override
public String toString(){
return word ":" count;
}
}运行示例
首先将flink运行起来，在docker-compose.yml所在目录下执行
代码语言：javascript复制$ docker-compose up -d
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
dc54c9cf6304 flink "/docker-entrypoint.…" 3 days ago Up 4 seconds 6121-6123/tcp, 8081/tcp flink_taskmanager_1
2eab6b0fd0f1 flink "/docker-entrypoint.…" 3 days ago Up 3 seconds 6123/tcp, 0.0.0.0:8081->8081/tcp flink_jobmanager_1可以看到两个实例已经启动了，然后新开一个终端窗口，运行nc监听程序。
代码语言：javascript复制$ nc -l 9008打开Flink界面，选择Submit New Job，上传编译好的jar包。
提交后可以看到运行的app已经收到了数据
使用docker logs -f命令，然后在nc窗口中输入一些单词，你就能够在docker窗口下看到统计结果输出了。
参考资料
- Flink-基于Docker的开发环境搭建
- Docker composer 快速入门
