我使用AvroCoder.class来序列化我的数据结构。我的代码如下：
@DefaultCoder(AvroCoder.class)
public class LogEntry {
public String sessionId;
public String status;
// time of the log entry.
public long timeStamp;
public LogEntry() {
}
}
当我尝试运行我的管道时，我得到以下例外：
java.lang.RuntimeException: Failed to construct instance from factory method com.google.cloud.dataflow.sdk.coders.AvroCoder#of
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:226)
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.build(InstanceBuilder.java:159)
at com.google.cloud.dataflow.sdk.coders.CoderRegistry.getDefaultCoder(CoderRegistry.java:605)
at com.google.cloud.dataflow.sdk.coders.CoderRegistry.getDefaultCoder(CoderRegistry.java:575)
at com.google.cloud.dataflow.sdk.coders.CoderRegistry.getDefaultCoder(CoderRegistry.java:556)
at com.google.cloud.dataflow.sdk.coders.CoderRegistry.getDefaultCoder(CoderRegistry.java:230)
at com.google.cloud.dataflow.sdk.transforms.Create.getElementCoder(Create.java:286)
at com.google.cloud.dataflow.sdk.transforms.Create.getDefaultOutputCoder(Create.java:308)
at com.google.cloud.dataflow.sdk.transforms.PTransform.getDefaultOutputCoder(PTransform.java:389)
at com.google.cloud.dataflow.sdk.values.TypedPValue.inferCoderOrFail(TypedPValue.java:149)
at com.google.cloud.dataflow.sdk.values.TypedPValue.getCoder(TypedPValue.java:44)
at com.google.cloud.dataflow.sdk.values.PCollection.getCoder(PCollection.java:105)
at com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner$Evaluator.ensureElementEncodable(DirectPipelineRunner.java:789)
at com.google.cloud.dataflow.sdk.transforms.Create.evaluateHelper(Create.java:384)
at com.google.cloud.dataflow.sdk.transforms.Create.access$200(Create.java:89)
at com.google.cloud.dataflow.sdk.transforms.Create$2.evaluate(Create.java:367)
at com.google.cloud.dataflow.sdk.transforms.Create$2.evaluate(Create.java:362)
at com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner$Evaluator.visitTransform(DirectPipelineRunner.java:619)
at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:200)
at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:196)
at com.google.cloud.dataflow.sdk.runners.TransformHierarchy.visit(TransformHierarchy.java:109)
at com.google.cloud.dataflow.sdk.Pipeline.traverseTopologically(Pipeline.java:204)
at com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner$Evaluator.run(DirectPipelineRunner.java:592)
at com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner.run(DirectPipelineRunner.java:328)
at com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner.run(DirectPipelineRunner.java:70)
at com.google.cloud.dataflow.sdk.Pipeline.run(Pipeline.java:145)
at sessions.SessionsDataflowTest.testComputeSessions(SessionsDataflowTest.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:219)
... 49 more
Caused by: java.lang.NoClassDefFoundError: org/apache/avro/reflect/AvroSchema
at com.google.cloud.dataflow.sdk.coders.AvroCoder$AvroDeterminismChecker.recurse(AvroCoder.java:354)
at com.google.cloud.dataflow.sdk.coders.AvroCoder$AvroDeterminismChecker.check(AvroCoder.java:347)
at com.google.cloud.dataflow.sdk.coders.AvroCoder.<init>(AvroCoder.java:164)
at com.google.cloud.dataflow.sdk.coders.AvroCoder.of(AvroCoder.java:117)
... 54 more
Caused by: java.lang.ClassNotFoundException: org.apache.avro.reflect.AvroSchema
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 58 more
如何修复此异常？我试图在测试中运行我的管道。我使用TestPipeline创建并运行我的测试。
答案 0 :(得分：1)
问题是我使用的旧版Avro（1.7.3）与Dataflow使用的Avro版本相冲突。我通过将我的pom文件更改为：
将我的管道中的Avro版本升级到最新版本<dependency>
<groupId>org.apache.avro</groupId>
<artifactId>avro</artifactId>
<version>[1.7.7,)</version>
</dependency>