Flink——Source

source 是flink的数据源，简单介绍四种读取数据的方式:

　　1.从集合中读取

　　2.从文件中读取

　　3.从kafka中读取

　　4.自定义Source

package com.jy.bjz.source;

import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.SourceFunction;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;

import java.util.Arrays;
import java.util.Properties;

/**
 * TODO
 *
 * @author baojiazhong
 * @since 2021/9/9 10:48
 */
public class SourceTest {
    public static void main(String[] args) {
        // 创建流式执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        // 读取 集合数据
        DataStream<Integer> collectionDataStream = env.fromCollection(Arrays.asList(1, 2, 3, 4));
        // 读取 文本数据 从路径中读取文件
        String path = "C:\\Users\\15868\\Desktop\\TL\\flink\\learn\\src\\main\\resources\\hello.txt";
        DataStream<String> textDataStream = env.readTextFile(path);
        // 读取 kafka数据
        // 配置kafka
        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers", "localhost:9092");
        properties.setProperty("group.id", "consumer-group");
        properties.setProperty("key.deserializer",
                "org.apacje.kafka.common.serialization.StringDeserializer");
        properties.setProperty("value.deserializer",
                "org.apache.kafka.common.serialization.StringDeserializer");
        properties.setProperty("auto.offset.reset", "latest");
        DataStream<String> test = env.addSource(new FlinkKafkaConsumer<String>("test", new SimpleStringSchema(), properties));
        // 自定义Source ， 实现 SourceFunction<T> 方法
        DataStreamSource<String> mySoucrceDataStream = env.addSource(new MySource());
    }

    public static class MySource implements SourceFunction<String> {

        public void run(SourceContext<String> ctx) throws Exception {
            // 读取数据
            ctx.collect("");
        }

        public void cancel() {
            //取消接收的条件
        }
    }
}