DataStream Data Sources

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

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        socketFunction(env);

        //nonParallelSourceFunction(env);

//        parallelSourceFunction(env);

//        richParallelSourceFunction(env);

        env.execute("JavaDataStreamSourceApp");

    }

1：socket方式：

public static void socketFunction(StreamExecutionEnvironment env) {

    DataStreamSource<String> data =  env.socketTextStream("localhost", 18082);

    data.print().setParallelism(1);

}

2：自定义数据源，并行数据源

  by implementing the  SourceFunction  for non-parallel sources,

 or 

by implementing the  ParallelSourceFunction  interface 

or 

extending the  RichParallelSourceFunction  for parallel sources.

public static void richParallelSourceFunction(StreamExecutionEnvironment env) {

    DataStreamSource<Long> data = env.addSource(new JavaCustomRichParallelSourceFunction()).setParallelism(2);

    data.print().setParallelism(1);

}

public static void parallelSourceFunction(StreamExecutionEnvironment env) {

    DataStreamSource<Long> data = env.addSource(new JavaCustomParallelSourceFunction()).setParallelism(2);

    data.print().setParallelism(2);

}

public static void nonParallelSourceFunction(StreamExecutionEnvironment env) {

    DataStreamSource<Long> data = env.addSource(new JavaCustomNonParallelSourceFunction());

            //.setParallelism(2);

    data.print().setParallelism(2);

}

JavaCustomNonParallelSourceFunction

package com.imooc.flink.java.course05;

import org.apache.flink.streaming.api.functions.source.SourceFunction;

/**

* Author: Michael PK

*/

public class JavaCustomNonParallelSourceFunction implements SourceFunction<Long> {

    boolean isRunning = true;

    long count = 1;

    public void run(SourceContext<Long> ctx) throws Exception {

        while (true) {

            ctx.collect(count);

            count += 1;

            Thread.sleep(1000);

        }

    }

    public void cancel() {

        isRunning = false;

    }

}

JavaCustomParallelSourceFunction

package com.imooc.flink.java.course05;

import org.apache.flink.streaming.api.functions.source.ParallelSourceFunction;

import org.apache.flink.streaming.api.functions.source.SourceFunction;

/**

* Author: Michael PK

*/

public class JavaCustomParallelSourceFunction implements ParallelSourceFunction<Long> {

    boolean isRunning = true;

    long count = 1;

    public void run(SourceContext<Long> ctx) throws Exception {

        while (true) {

            ctx.collect(count);

            count += 1;

            Thread.sleep(1000);

        }

    }

    public void cancel() {

        isRunning = false;

    }

}

JavaCustomRichParallelSourceFunction

package com.imooc.flink.java.course05;

import org.apache.flink.configuration.Configuration;

import org.apache.flink.streaming.api.functions.source.RichParallelSourceFunction;

/**

* Author: Michael PK

*/

public class JavaCustomRichParallelSourceFunction extends RichParallelSourceFunction<Long> {

    boolean isRunning = true;

    long count = 1;

    public void run(SourceContext<Long> ctx) throws Exception {

        while (true) {

            ctx.collect(count);

            count += 1;

            Thread.sleep(1000);

        }

    }

    @Override

    public void open(Configuration parameters) throws Exception {

        super.open(parameters);

    }

    @Override

    public void close() throws Exception {

        super.close();

    }

    public void cancel() {

        isRunning = false;

    }

}