flink Data Source数据源

flink

Data Source数据源

Source

• 并行度

  • 非并行：并行度只能为1

  • 并行

• 基于集合的Source

  • fromElements

    • package com.pxj.sx.flink;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.RestOptions;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

public class FromElementDemo {
   
   
    public static void main(String[] args) throws Exception {
   
   
        Configuration configuration = new Configuration();
        configuration.setInteger(RestOptions.PORT, 8081);
        StreamExecutionEnvironment env = StreamExecutionEnvironment.createLocalEnvironmentWithWebUI(configuration);
//        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        DataStreamSource<String> daat = env.fromElements("flink", "spark", "hive");
        daat.print();


        Thread.sleep(2000000);
    }
}

	- fromElements(T ...) 方法是一个非并行的Source，可以将一到多个数据作为可变参数传入到该方法中，返回DataStreamSource。该方法返回的DataStream是一个有限数据流，数据读完后，程序退出，通常用于开发测试。

-  fromCollection

	- fromCollection可以从一个结合读取数据，返回DataStream，该方法返回的DataStream是一个有限数据流，数据读完后，程序退出，通常用于开发测试。

		- package com.pxj.sx.flink;

import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

import java.util.Arrays;
import java.util.List;

public class FromCollectionDemo {
   
   
    public static void main(String[] args) throws Exception {
   
   
         StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
         List<String> wordList = Arrays.asList("flink", "spark", "hadoop", "flink");
         DataStreamSource<String> source = env.fromCollection(wordList);
         source.print(