大数据-124 - Flink State 01篇 状态原理和原理剖析：状态类型 执行分析

package icu.wzk;

import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.api.common.state.ValueState;
import org.apache.flink.api.common.state.ValueStateDescriptor;
import org.apache.flink.api.common.typeinfo.TypeHint;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;


public class FlinkStateTest01 {

    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);
        DataStreamSource<Tuple2<Long, Long>> data = env
                .fromElements(
                        Tuple2.of(1L, 3L),
                        Tuple2.of(1L, 5L),
                        Tuple2.of(1L, 7L),
                        Tuple2.of(1L, 4L),
                        Tuple2.of(1L, 2L)
                );
        KeyedStream<Tuple2<Long, Long>, Long> keyed = data
                .keyBy(new KeySelector<Tuple2<Long, Long>, Long>() {
                    @Override
                    public Long getKey(Tuple2<Long, Long> value) throws Exception {
                        return value.f0;
                    }
                });
        SingleOutputStreamOperator<Tuple2<Long, Long>> flatMapped = keyed
                .flatMap(new RichFlatMapFunction<Tuple2<Long, Long>, Tuple2<Long, Long>>() {
                    private transient ValueState<Tuple2<Long, Long>> sum;

                    @Override
                    public void flatMap(Tuple2<Long, Long> value, Collector<Tuple2<Long, Long>> out) throws Exception {
                        Tuple2<Long, Long> currentSum = sum.value();
                        if (currentSum == null) {
                            currentSum = Tuple2.of(0L, 0L);
                        }
                        // 更新
                        currentSum.f0 += 1L;
                        currentSum.f1 += value.f1;
                        System.out.println("currentValue: " + currentSum);
                        // 更新状态值
                        sum.update(currentSum);
                        // 如果 count >= 5 清空状态值 重新计算
                        if (currentSum.f0 >= 5) {
                            out.collect(new Tuple2<>(value.f0, currentSum.f1 / currentSum.f0));
                            sum.clear();
                        }
                    }

                    @Override
                    public void open(Configuration parameters) throws Exception {
                        ValueStateDescriptor<Tuple2<Long, Long>> descriptor = new ValueStateDescriptor<>(
                                "average",
                                TypeInformation.of(new TypeHint<Tuple2<Long, Long>>() {})
                        );
                        sum = getRuntimeContext().getState(descriptor);
                    }
                });
        flatMapped.print();
        env.execute("Flink State Test");
    }
}