spark程序里使用了jackson去做scala对象的json序列化和反序列化。运行时出现java.lang.NoClassDefFoundError和java.lang.AbstractMethodError错误,网上搜了一下发现是jackson/guava和spark本身带的版本冲突。
1.在idea中,通过调整modules中依赖的先后次序,很快解决了问题:
Edit->File Structure->Modules->Dependencies
2.发布到Spark集群上,由于某种原因一开始没有用maven来管理项目,所以还是想通过调整对第3方库的依赖次序来解决:
spark-submit --class noc.train.Train --master yarn-client --num-executors 10 --executor-cores 2 --driver-memory 10g --executor-memory 12g --conf spark.yarn.executor.memoryOverhead=2048 \
--conf spark.executor.extraClassPath=./guava-15.0.jar:./jackson-annotations-2.4.4.jar:./jackson-core-2.4.4.jar:./jackson-databind-2.4.4.jar:./jackson-module-scala_2.10-2.4.4.jar \
--conf spark.driver.extraClassPath=/home/ck/lib/guava-15.0.jar:/home/ck/lib/jackson-annotations-2.4.4.jar:/home/ck/lib/jackson-core-2.4.4.jar:/home/ck/lib/jackson-databind-2.4.4.jar:/home/ck/lib/jackson-module-scala_2.10-2.4.4.jar \
--jars /home/ck/lib/guava-15.0.jar,/home/ck/lib/jackson-annotations-2.4.4.jar,/home/ck/lib/jackson-core-2.4.4.jar,/home/ck/lib/jackson-databind-2.4.4.jar,/home/ck/lib/jackson-module-scala_2.10-2.4.4.jar \
/home/ck/noc_scala.jar
但错误依旧:
18/09/12 09:46:47 INFO scheduler.TaskSetManager: Lost task 198.0 in stage 7.0 (TID 897) on executor host-9-136: java.lang.NoClassDefFoundError (Could not initialize class noc.grid.Grid$) [duplicate 1]
18/09/12 09:46:47 WARN scheduler.TaskSetManager: Lost task 58.0 in stage 7.0 (TID 890, host-9-136): java.lang.AbstractMethodError: noce.grid.Grid$$anon$1.com$fasterxml$jackson$module$scala$experimental$ScalaObjectMapper$_setter_$com$fasterxml$jackson$module$scala$experimental$ScalaObjectMapper$$typeCache_$eq(Lorg/spark-project/guava/cache/LoadingCache;)V
at com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper$class.$init$(ScalaObjectMapper.scala:50)
只好求助maven
3.使用maven的shade插件:
首先增加依赖项,使用默认的compile scope
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-scala_2.10</artifactId>
<version>2.4.4</version>
</dependency>
然后增加maven-shade-plugin
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.1.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<relocations>
<relocation>
<pattern>com.fasterxml.jackson</pattern>
<shadedPattern>noc.com.fasterxml.jackson</shadedPattern>
</relocation>
<relocation>
<pattern>com.google.guava</pattern>
<shadedPattern>noc.com.google.guava</shadedPattern>
</relocation>
</relocations>
</configuration>
</execution>
</executions>
Done!