小编ilp*_*ina的帖子

我正在尝试通过 Docker 连接到单节点 Kafka 服务器，但出现以下错误：

%3|1529395526.480|FAIL|rdkafka#producer-1| [thrd:localhost:9092/bootstrap]: localhost:9092/bootstrap: Connect to ipv4#127.0.0.1:9092 failed: Connection refused
%3|1529395526.480|ERROR|rdkafka#producer-1| [thrd:localhost:9092/bootstrap]: localhost:9092/bootstrap: Connect to ipv4#127.0.0.1:9092 failed: Connection refused
%3|1529395526.480|ERROR|rdkafka#producer-1| [thrd:localhost:9092/bootstrap]: 1/1 brokers are down

docker-compose.yml 文件内容如下：

version: '2'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper:latest
    network_mode: host
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
    extra_hosts:
      - "moby:127.0.0.1"

  kafka:
    image: confluentinc/cp-kafka:latest
    network_mode: host
    depends_on:
      - zookeeper
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: localhost:2181
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092
      KAFKA_ADVERTISED_HOSTNAME: kafka
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
    extra_hosts:
      - "moby:127.0.0.1"

  schema_registry:
    image: confluentinc/cp-schema-registry
    hostname: schema_registry
    depends_on:
      - zookeeper
      - kafka
    ports: …

我在 Scala 中有以下代码：

val FilteredPSPDF = PSPDF.select("accountname","amount", "currency", "datestamp","orderid","transactiontype")

但是，我在“金额”列中有一些值为负的值，我需要将它们更改为正值。是否可以在 Select 语句中执行此算术函数？我该怎么做？