先说下版本情况：
Spark 2.4.3
Scala 2.11.12
Flume-1.6.0
Flume 配置文件：
simple-agent.sources = netcat-source
simple-agent.sinks = spark-sink
simple-agent.channels = memory-channel
#Describe/configure the source
simple-agent.sources.netcat-source.type = netcat
simple-agent.sources.netcat-source.bind =centos
simple-agent.sources.netcat-source.port= 44444
# Describe the sink
simple-agent.sinks.spark-sink.type=org.apache.spark.streaming.flume.sink.SparkSink
simple-agent.sinks.spark-sink.hostname= centos
simple-agent.sinks.spark-sink.port= 41414
simple-agent.channels.memory-channel.type = memory
simple-agent.sources.netcat-source.channels = memory-channel
simple-agent.sinks.spark-sink.channel = memory-channel启动脚本：
flume-ng agent --name simple-agent --conf $FLUME_HOME/conf --conf-file $FLUME_HOME/conf/flume_pull.conf -Dflume.root.logger=INFO,console 到以上步骤均没有出现问题。但是将本地测试代码启动，尝试与 Flume 的 sink 进行连接时，崩了 …
Flume 控制台报错：
2019-10-16 16:42:35,364 (New I/O worker #1) [WARN - org.apache.avro.ipc.Responder.respond(Responder.java:174)] system error
org.apache.avro.AvroRuntimeException: Unknown datum type: java.lang.Exception: java.lang.NoClassDefFoundError: Could not initialize class org.apache.spark.streaming.flume.sink.EventBatch
at org.apache.avro.generic.GenericData.getSchemaName(GenericData.java:593)
at org.apache.avro.generic.GenericData.resolveUnion(GenericData.java:558)
at org.apache.avro.generic.GenericDatumWriter.resolveUnion(GenericDatumWriter.java:144)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:71)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:58)
at org.apache.avro.ipc.specific.SpecificResponder.writeError(SpecificResponder.java:74)
at org.apache.avro.ipc.Responder.respond(Responder.java:169)
at org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.messageReceived(NettyServer.java:188)
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
at org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:173)
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:558)
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:786)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:296)
at org.jboss.netty.handler.codec.frame.FrameDecoder.unfoldAndFireMessageReceived(FrameDecoder.java:458)
at org.jboss.netty.handler.codec.frame.FrameDecoder.callDecode(FrameDecoder.java:439)
at org.jboss.netty.handler.codec.frame.FrameDecoder.messageReceived(FrameDecoder.java:303)
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:558)
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:553)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:84)
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.processSelectedKeys(AbstractNioWorker.java:471)
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:332)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:35)
at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:102)
at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
2019-10-16 16:42:35,380 (New I/O worker #1) [WARN - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.exceptionCaught(NettyServer.java:201)] Unexpected exception from downstream.
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:192)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:59)
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.processSelectedKeys(AbstractNioWorker.java:471)
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:332)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:35)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecuto本地 IDE 控制台：
10/16 16:56:38 ERROR Requestor: Error in callback handler: java.lang.IllegalAccessError: tried to access method org.apache.avro.specific.SpecificData.<init>()V from class org.apache.spark.streaming.flume.sink.EventBatch
java.lang.IllegalAccessError: tried to access method org.apache.avro.specific.SpecificData.<init>()V from class org.apache.spark.streaming.flume.sink.EventBatch解决思路
既然都有这个 org.apache.spark.streaming.flume.sink.EventBatch, 所幸就看看代码吧
package org.apache.spark.streaming.flume.sink;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.message.BinaryMessageEncoder;
import org.apache.avro.message.BinaryMessageDecoder;
import org.apache.avro.message.SchemaStore;
@SuppressWarnings("all")
@org.apache.avro.specific.AvroGenerated
public class EventBatch extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
private static final long serialVersionUID = -2739787017790252011L;
public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"EventBatch\",\"namespace\":\"org.apache.spark.streaming.flume.sink\",\"fields\":[{\"name\":\"errorMsg\",\"type\":\"string\",\"default\":\"\"},{\"name\":\"sequenceNumber\",\"type\":\"string\"},{\"name\":\"events\",\"type\":{\"type\":\"array\",\"items\":{\"type\":\"record\",\"name\":\"SparkSinkEvent\",\"fields\":[{\"name\":\"headers\",\"type\":{\"type\":\"map\",\"values\":\"string\"}},{\"name\":\"body\",\"type\":\"bytes\"}]}}}]}");
public static org.apache.avro.Schema getClassSchema() { return SCHEMA$;}
private static SpecificData MODEL$ = new SpecificData();
private static final BinaryMessageEncoder<EventBatch> ENCODER =
new BinaryMessageEncoder<EventBatch>(MODEL$, SCHEMA$);
private static final BinaryMessageDecoder<EventBatch> DECODER =
new BinaryMessageDecoder<EventBatch>(MODEL$, SCHEMA$); 在 IDEA 中可以看到 org.apache.avro.message.BinaryMessageEncoder; 这行是红色的，没有找到该方法。然后我就搜索了一下，
果然是我用的 avro 版本过旧。
解决方案
1. 在代码的 pom.xml 中添加以下依赖。
<!-- https://mvnrepository.com/artifact/org.apache.avro/avro -->
<dependency>
<groupId>org.apache.avro</groupId>
<artifactId>avro</artifactId>
<version>1.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.avro/avro-ipc -->
<dependency>
<groupId>org.apache.avro</groupId>
<artifactId>avro-ipc</artifactId>
<version>1.8.2</version>
</dependency>2. 将以上两个 jar 包上传至 $FLUME_HOME/lib 下，并删除旧的 avro jar 包。
欢迎关注我的公号：彪悍大蓝猫，持续分享大数据、SpringCloud 干货~