How to use Flink Min to get the smallest value in a set of data streams
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Min aggregation: gets the smallest value in a set of data streams (as opposed to max)
Sample environment
Java.version: 1.8.xflink.version: 1.11.1
Sample data source (project code cloud download)
Building Development Environment and data of Flink system example
Min.java
Import com.flink.examples.DataSource;import org.apache.flink.api.common.functions.MapFunction;import org.apache.flink.api.common.typeinfo.Types;import org.apache.flink.api.java.functions.KeySelector;import org.apache.flink.api.java.tuple.Tuple2;import org.apache.flink.api.java.tuple.Tuple3;import org.apache.flink.streaming.api.datastream.DataStream;import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;import java.util.List / * * @ Description min aggregation: get the smallest value in a set of data streams (as opposed to max) * / public class Min {/ * traversal collection, and return the minimum age * @ param args * @ throws Exception * / public static void main (String [] args) throws Exception {final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment (); List tuple3List = DataSource.getTuple3ToList () DataStream dataStream = env.fromCollection (tuple3List) .map (new MapFunction () {@ Override public Tuple2 map (Tuple3 tuple3) throws Exception {return new Tuple2 (tuple3.f1,tuple3.f2) }}) .returns (Types.TUPLE (Types.STRING,Types.INT)) .keyby ((KeySelector) k-> k.f0) / / scroll by the quantity window, calculating every 3 input data streams. CountWindow (3) .min (1) DataStream.print (); env.execute ("flink Min job");}}
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