Flink-源算子Source(获取数据源)的使用

5.1 整体介绍

1. 获取执行环境
2. 读取数据源
3. 定义基于数据的转换操作
4. 定义计算结果的输出位置
5. 触发程序执行

5.2 创建集成环境

5.2.1 获取执行环境

1. 批处理getExecutionEnvironment

• 提交命令行设置

bin/flink run -Dexecution.runtime-mode=BATCH ...

• 代码

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

使用StreamExecutionEnvironment类调用getExecutionEnvironment的方法[不推荐，直接写死了]

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setRuntimeMode(RuntimeExecutionMode.BATCH);

设置setRuntimeMode 方法，传入 BATCH 模式

2. 流处理

// 批处理环境
ExecutionEnvironment batchEnv = ExecutionEnvironment.getExecutionEnvironment();
// 流处理环境
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

5.3 源算子

5.3.1 读取有界流

1. 数据准备

• 基本数据类型

import java.sql.Timestamp;

public class Event {
    public String user;
    public String url;
    public Long timestamp;

    //无参构造方法
    public Event() {
    }

    public Event(String user, String url, Long timestamp) {
        this.user = user;
        this.url = url;
        this.timestamp = timestamp;
    }

    @Override
    public String toString() {
        return "Event{" +
                "user='" + user + '\'' +
                ", url='" + url + '\'' +
                ", timestamp=" + new Timestamp(timestamp) +
                '}';
    }
}

基本数据类型有:用户名、url以及时间戳

• 文件

Mary,./home,1000
Alice,./cart,2000
Bob,./prod?id=100,3000
Bob,./cart,4000
Bob,./home,5000
Mary,./home,6000
Bob,./cart,7000
Bob,./home,8000
Bob,./prod?id=10,9000

2. 代码

3种了，从文件，从集合，从元素

public class SourceTest {
    public static void main(String[] args) throws Exception{
        //1.创建执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        //2.从文件中读取数据（有界流）
        DataStreamSource<String> stream1 = env.readTextFile("input/clicks.txt");


        //3.从集合中读取数据
        ArrayList<Integer> nums = new ArrayList<>();
        nums.add(2);
        nums.add(5);
        DataStreamSource<Integer> numsStream = env.fromCollection(nums);

        //泛型选择event，从event读取数据
        ArrayList<Event> events = new ArrayList<>();
        events.add(new Event("Mary","./home",1000L));
        events.add(new Event("Bob","./cart",2000L));
        DataStreamSource<Event> stream2 = env.fromCollection(events);


        //4.从元素读取数据
        //不用通过数组中间装载，直接可以放到fromElement中
        DataStreamSource<Event> stream3 = env.fromElements(new Event("Mary", "./home", 1000L),
                new Event("Bob", "./cart", 2000L));

        stream1.print();
        numsStream.print();
        stream2.print();
        stream3.print();
        env.execute();

            }
}

3. 结果

2
5
Event{user='Mary', url='./home', timestamp=1970-01-01 08:00:01.0}
Event{user='Mary', url='./home', timestamp=1970-01-01 08:00:01.0}
Event{user='Bob', url='./cart', timestamp=1970-01-01 08:00:02.0}
Event{user='Bob', url='./cart', timestamp=1970-01-01 08:00:02.0}
Mary,./home,1000
Alice,./cart,2000
Bob,./prod?id=100,3000
Bob,./cart,4000
Bob,./home,5000
Mary,./home,6000
Bob,./cart,7000
Bob,./home,8000
Bob,./prod?id=10,9000

Process finished with exit code 0

5.3.2 从socket读取数据

1. 启动hadoop2虚拟机中的nc -lk
2. 代码

//5.从socket文本流读取
        DataStreamSource<String> stream4 = env.socketTextStream("hadoop2", 7777);
        stream4.print();
        env.execute();

3. 结果

5.3.3 读取kafka

1. 引入连接器依赖

<dependency>
 <groupId>org.apache.flink</groupId>
 <artifactId>flink-connector-kafka_${scala.binary.version}</artifactId>
 <version>${flink.version}</version>
</dependency>

2. 启动kafka

• 启动zk和kadfa

[hadoop1@hadoop2 kafka]$ ./bin/zookeeper-server-start.sh -daemon ./config/zookeeper.properties

[hadoop1@hadoop2 kafka]$ ./bin/kafka-server-start.sh -daemon ./config/server.properties

• 启动生产者

[hadoop1@hadoop2 kafka]$ ./bin/kafka-console-producer.sh --broker-list localhost:9092 --topic clicks

3. 启动程序

使用addSource方法中传入flink连接器传入的FlinkKafkaConsumer

//6.从kafka读取数据

        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers","hadoop2:9092");
        properties.setProperty("group.id", "consumer-group");
        properties.setProperty("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        properties.setProperty("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        properties.setProperty("auto.offset.reset", "latest");
        DataStreamSource<String> kafkaStream = env.addSource(new FlinkKafkaConsumer<String>("clicks", new SimpleStringSchema(), properties));
        kafkaStream.print();
        env.execute();

• 结果

5.3.4 自定义Source

1. 思路

自定义实现SourceFunction接口，重写两个方法run()和cancel()

2. 代码

public class SourceCustomTest {
    public static void main(String[] args) throws Exception{
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        DataStreamSource<Event> customStream = env.addSource(new ClickSource());
        customStream.print();
        env.execute();

    }
}

• 自定义的ClickSource

public class ClickSource implements SourceFunction<Event> {

    //声明一个标志位控制数据生成
    private Boolean running = true;
    @Override
    //泛型为Event
    public void run(SourceContext<Event> ctx) throws Exception {

        //随机生成数据
        Random random = new Random();
        //定义字段选取的数据集
        String[] users = {"Mary","Alice","Bob","Cary"};
        String[] urls = {"./home","./cart","./fav","./prod?id=100","/prod?id=10"};

        //一直循环生成数据
        while (running){
            String user = users[random.nextInt(users.length-1)];
            String url = users[random.nextInt(urls.length-1)];
            //系统当前事件的毫秒数
            Long timestamp = Calendar.getInstance().getTimeInMillis();
            //collect收集Event发往下游
            ctx.collect(new Event(user,url,timestamp));

            Thread.sleep(1000L);
        }
    }

    @Override
    public void cancel() {
        running =false;
    }
}

3. 结果

5.3.5 自定义并行Source

1. 分析

传入的还是SourceFunction，于是说如果是继承了ParallelSourceFunction的话，就可以设置并行度

2. 代码

public class SourceCustomTest {
    public static void main(String[] args) throws Exception{
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        //DataStreamSource<Event> customStream = env.addSource(new ClickSource());
        //这边并行度改成2
        DataStreamSource<Integer> customStream = env.addSource(new ParallelCustomSource())
                .setParallelism(2);
        customStream.print();
        env.execute();
    }

    //定义一个静态类吧
    //实现自定义的并行SourceFunction
    public static class ParallelCustomSource implements ParallelSourceFunction<Integer> {

        //同样来一个标志位
        private Boolean running =true;
        private Random random = new Random();

        @Override
        public void run(SourceContext<Integer> ctx) throws Exception {
            while (running){
                ctx.collect(random.nextInt());
                Thread.sleep(1000L);
            }


        }

        @Override
        public void cancel() {
            running = false;
        }
    }
}

2. 结果