我正在尝试编写自定义接收器，但收到以下错误 -
错误： -
Exception in thread "dispatcher-event-loop-1" java.lang.NoClassDefFoundError: scala/runtime/AbstractPartialFunction$mcVL$sp
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
pom文件
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.bnr</groupId>
<artifactId>oos_detction</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>oos_detction</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<scalaVersion>2.11.0</scalaVersion><!-- -->
</properties>
<dependencies>
<!-- Import Spark -->
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.11</artifactId>
<version>2.0.2</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.microsoft.azure</groupId>
<artifactId>azure-storage</artifactId>
<version>5.5.0</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming_2.10</artifactId>
<version>2.0.2</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
这是我的代码： -
import com.google.common.io.Closeables;
import org.apache.spark.SparkConf;
import org.apache.spark.storage.StorageLevel;
import org.apache.spark.streaming.Duration;
import org.apache.spark.streaming.api.java.JavaDStream;
import org.apache.spark.streaming.api.java.JavaPairDStream;
import org.apache.spark.streaming.api.java.JavaReceiverInputDStream;
import org.apache.spark.streaming.api.java.JavaStreamingContext;
import org.apache.spark.streaming.receiver.Receiver;
import scala.Tuple2;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.ConnectException;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.regex.Pattern;
/**
* Custom Receiver that receives data over a socket. Received bytes is interpreted as
* text and \n delimited lines are considered as records. They are then counted and printed.
*
* Usage: JavaCustomReceiver <master> <hostname> <port>
* <master> is the Spark master URL. In local mode, <master> should be 'local[n]' with n > 1.
* <hostname> and <port> of the TCP server that Spark Streaming would connect to receive data.
*
* To run this on your local machine, you need to first run a Netcat server
* `$ nc -lk 9999`
* and then run the example
* `$ bin/run-example org.apache.spark.examples.streaming.JavaCustomReceiver localhost 9999`
*/
public class JavaCustomReceiver extends Receiver<String> {
private static final Pattern SPACE = Pattern.compile(" ");
public static void main(String[] args) throws Exception {
// if (args.length < 2) {
// System.err.println("Usage: JavaCustomReceiver <hostname> <port>");
// System.exit(1);
// }
// StreamingExamples.setStreamingLogLevels();
// Create the context with a 1 second batch size
SparkConf sparkConf = new SparkConf().setAppName("JavaCustomReceiver").setMaster("local[*]");
JavaStreamingContext ssc = new JavaStreamingContext(sparkConf, new Duration(30000));
// Create an input stream with the custom receiver on target ip:port and count the
// words in input stream of \n delimited text (eg. generated by 'nc')
JavaReceiverInputDStream<String> lines = ssc.receiverStream(
new JavaCustomReceiver("localhost", 9999));
System.out.println("This is a test message");
// JavaDStream<String> words = lines.flatMap(x -> Arrays.asList(SPACE.split(""))).iterator();
JavaDStream<String> words = lines.flatMap(x -> Arrays.asList(SPACE.split(" ")).iterator());
JavaPairDStream<String, Integer> wordCounts = words.mapToPair(s -> new Tuple2<>(s, 1))
.reduceByKey((i1, i2) -> i1 + i2);
System.out.println("WordCounts == " + wordCounts);
wordCounts.print();
ssc.start();
ssc.awaitTermination();
}
// ============= Receiver code that receives data over a socket ==============
String host = null;
int port = -1;
public JavaCustomReceiver(String host_ , int port_) {
super(StorageLevel.MEMORY_AND_DISK_2());
host = host_;
port = port_;
}
@Override
public void onStart() {
// Start the thread that receives data over a connection
new Thread(this::receive).start();
}
@Override
public void onStop() {
// There is nothing much to do as the thread calling receive()
// is designed to stop by itself isStopped() returns false
}
/** Create a socket connection and receive data until receiver is stopped */
private void receive() {
try {
Socket socket = null;
BufferedReader reader = null;
try {
// connect to the server
socket = new Socket(host, port);
reader = new BufferedReader(
new InputStreamReader(socket.getInputStream(), StandardCharsets.UTF_8));
// Until stopped or connection broken continue reading
String userInput;
while (!isStopped() && (userInput = reader.readLine()) != null) {
System.out.println("Received data '" + userInput + "'");
store(userInput);
}
} finally {
Closeables.close(reader, /* swallowIOException = */ true);
Closeables.close(socket, /* swallowIOException = */ true);
}
// Restart in an attempt to connect again when server is active again
restart("Trying to connect again");
} catch(ConnectException ce) {
// restart if could not connect to server
restart("Could not connect", ce);
} catch(Throwable t) {
restart("Error receiving data", t);
}
}
}
答案 0 :(得分：2)
问题是库版本不匹配。
请注意，后缀_2.10（用于spark-streaming_2.10模块）或2.11（用于spark-core_2.11模块）告诉sbt下载不同版本的Scala（以及其他传递依赖项） ）这可能导致像你这样的错误。
要解决您的问题，请使用spark-streaming_2.11（请注意_2.11后缀）。