将FSON格式的数据从Flink写入文件

Question

当我们尝试使用 writeAsCsv（path，writemode）方法将处理过的JSON数据从Flink写入文件时，数据写入文件但我们需要在每个JSON后插入逗号这没有发生。我们使用Apache Kafka作为Flink的数据源。

DataStream<Tuple5<String, String, String, String, String>> messageStream = env.addSource(new FlinkKafkaConsumer08<>(FLINK_TOPIC, new SimpleStringSchema(), properties)).flatMap(new StreamToTuple5()).keyBy(0);
String path = "/home/user/Documents/docs/csvfile/";
messageStream.writeAsCsv(path, FileSystem.WriteMode.OVERWRITE);

执行此方法时获得的输出是

{"temperSensorData":"28.489084691371364","temperSensorUnit":"celsius","timestamp":"1493270680759","timestamp2":"1493270680786","timestamp3":"1493270680787"}
{"temperSensorData":"28.489084691371467","temperSensorUnit":"celsius","timestamp":"1493270680761","timestamp2":"1493270680816","timestamp3":"1493270680816"}

Answer 1

您可以通过将','指定为行分隔符来解决您的问题：

messageStream.writeAsCsv(path, FileSystem.WriteMode.OVERWRITE, ",", ",")

这里的第三个参数是行分隔符。