flink 文档中给出的代码无法编译

Question

我对 flink 很陌生，并且正在尝试在 flink 文档中给出的一些代码。

flink 文档中的代码：

public class WordWithCount {
    public String word;
    public long count;
    public WordWithCount() {}
    public WordWithCount(String word, int count) {
        this.word = word;
        this.count = count;
    }
}
DataStream<Tuple2<String, Long>> wordCounts = env.fromElements(
    new WordWithCount("hello", 1),
    new WordWithCount("world", 2));
wordCounts.keyBy("word"); // key by field expression "word"

但是我在

DataStream<Tuple2<String, Long>> wicstream = sev.fromElements(new WordwithCount("Hello",1), new WordwithCount("hello",1)); 

错误信息：

Type mismatch: cannot convert from DataStreamSource<WordwithCount> to DataStream<Tuple2<String,Long>>

请帮助我理解我的错误。

Answer 1

DataStream的类型应为 X，与您提供给fromElements()方法的对象类型相同。您提供WordwithCount作为参数，因此DataStream的类型应WordwithCount。

您的代码应如下所示：

DataStream<WordwithCount> wicstream = sev.fromElements(new WordwithCount("Hello",1), new WordwithCount("hello",1));