Apache Flink："Class X does not contain a setter for field Y"是什么意思？

Question

我第一次玩flink(1.6，1.7(，并使用github存档中的数据https://www.gharchive.org/但是使用该数据作为流数据源。

我的简单示例只是统计每个用户每天窗口的所有事件，我正试图复制相同的示例，但使用TableEnvironment和SQL支持。

然而，我遇到了以下错误：

class org.apache.flink.streaming.api.functions.source.TimestamphFileInputSplit不包含字段修改的setter时间如下所示：

8-12-04 14:17:02:115  INFO main exploration.StreamingTableApp:32 - Starting Streaming Table Flink App Example...
18-12-04 14:17:02:174  INFO main typeutils.TypeExtractor:1818 - class org.apache.flink.streaming.api.functions.source.TimestampedFileInputSplit does not contain a setter for field modificationTime
18-12-04 14:17:02:176  INFO main typeutils.TypeExtractor:1857 - Class class org.apache.flink.streaming.api.functions.source.TimestampedFileInputSplit cannot be used as a POJO type because not all fields are valid POJO fields, and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance.
18-12-04 14:17:02:937  INFO main exploration.StreamingTableApp:74 - Finished...

我将CSV源作为数据流进行读取，并使用Gson解析json行的部分，并将这些属性映射到Tuple。

有人对此有什么想法/经验吗？

主要方法：

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
// Mapped in docker compose file too.
DataStreamSource<String> input = env.readTextFile("/some/path/github/");
// Setup the stream
DataStream<Tuple4<String, Integer, String, Long>> stream = input.map(new GithubTupleConverter())
.assignTimestampsAndWatermarks(new TupleTimestampExtractor());
StreamTableEnvironment tEnv = TableEnvironment.getTableEnvironment(env);
Table tableFromStream = tEnv.fromDataStream(stream, "user_id, kount, basic_date,event_date");

TupleTimestampExtractor

public class TupleTimestampExtractor
extends BoundedOutOfOrdernessTimestampExtractor<Tuple4<String, Integer, String, Long>> {
private static final long serialVersionUID = 3737675541965835242L;
public TupleTimestampExtractor() {
super(Time.seconds(30L));
}
@Override
public long extractTimestamp(Tuple4<String, Integer, String, Long> element) {
return element.getField(3);
}
}

GithubTupleConverter.java

public class GithubTupleConverter implements MapFunction<String, Tuple4<String, Integer, String, Long>> {
private static final Gson g = new Gson();
@Override
public Tuple4<String, Integer, String, Long> map(String value) throws Exception {
// Take each line as Json.
JsonObject o = g.fromJson(value, JsonObject.class);
// Extract the user id
String userId = o.get("actor").getAsJsonObject().get("login").getAsString();
// Extract the event type (commit, pull request, fork event)
String type = o.get("type").getAsString();
// Get the event date time
String dateTime = o.get("created_at").getAsString();
// Parse date string to Typed type.
LocalDateTime eventTime = LocalDateTime.parse(dateTime, DateTimeFormatter.ISO_DATE_TIME);
// Format the date so it can be used in the output.
DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE;
return Tuple4.of(userId, 1, formatter.format(eventTime), eventTime.toInstant(ZoneOffset.UTC).toEpochMilli());
}
} 

Answer 1

您共享的日志不会显示错误。日志处于INFO级别，不会引发异常(至少在提供的日志中没有(。

日志条目只是说类TimestampedFileInputSplit不能被视为POJO。通常，此消息表示性能不是最佳的，但在这种特殊情况下，这不是问题。

你收到其他错误消息了吗？