Apache Flink - Error: method apply not applicable for the arguments (WindowFunction)

Apache Flink - Error: method apply not applicable for the arguments (WindowFunction)

我是 Apache Flink 的新手。我从 Apache Kafka 源读取数据并需要转换 DataStream

在最后一步,我尝试应用 WindowFunction:

DataStream<Tuple8<Double, Double, String, Double, Double, Double, Double, Double>> dataStream = 
                     env
                    .addSource(new FlinkKafkaConsumer08<>(
                                    parameterTool.getRequired("topic"),
                                    new SimpleStringSchema(), 
                                    parameterTool.getProperties()))
                    .flatMap(new SplitIntoRecordsString())
                    .flatMap(new SplitIntoTuples())
                    .keyBy(1)
                    .countWindow(5)
                    .apply(new windowApplyFunction());

    public class windowApplyFunction implements WindowFunction<
                                                            Tuple8<Double, Double, String, Double, Double, Double, Double, Double>, 
                                                            String,  
                                                            Double, 
                                                            Window>{

    public void apply(Double key, Window window,
            Iterable<Tuple8<Double, Double, String, Double, Double, Double, Double, Double>> values,
            Collector<String> out)
            throws Exception {      
        out.collect("MyResult");
    }
}

不幸的是,我收到以下错误并且不知道如何修复它:

The method apply(WindowFunction<Tuple8<Double,Double,String,Double,Double,Double,Double,Double>,R,Tuple,GlobalWindow>) in the type WindowedStream<Tuple8<Double,Double,String,Double,Double,Double,Double,Double>,Tuple,GlobalWindow> is not applicable for the arguments (FlinkManager.windowApplyFunction)

如果我用预定义函数替换 apply(new windowApplyFunction()),一切正常,例如sum(1).

您的 WindowFunction 类型应为

WindowFunction<
    Tuple8<Double, Double, String, Double, Double, Double, Double, Double>,
    String,
    Double,
    GlobalWindow>

countWindow() returns GlobalWindow 类型.

试一试。

感谢 vanekjar 的提示!纠正这个错误后,我改变了另一个小东西,现在可以用了! 正确代码:

public static class windowApplyFunction implements WindowFunction<
                                                            Tuple8<Double, Double, String, Double, Double, Double, Double, Double>, 
                                                            Tuple8<Double, Double, String, Double, Double, Double, Double, Double>, 
                                                            Tuple, 
                                                            GlobalWindow>{

    public void apply(Tuple key, GlobalWindow window,
            Iterable<Tuple8<Double, Double, String, Double, Double, Double, Double, Double>> values,
            Collector<Tuple8<Double, Double, String, Double, Double, Double, Double, Double>> out)
            throws Exception {      
        out.collect(new Tuple8<Double, Double, String, Double, Double, Double, Double, Double>());
    }
}