Jackson："Conflicting setter definitions for property" 在 JUnit 测试中

Question

我有一个使用 Amazon 的 AWS SDK for Java 查询 EC2 Instance 数据的应用程序。使用 AWS SDK 中包含的 Jackson 包装器 class 将实例序列化为 JSON 字符串。稍后，我可以使用 Jackson.fromJsonString(String, Class) 方法将 JSON 字符串反序列化回 EC2 Instance 对象。

这一切在我的应用程序代码中都非常有效。但是，当运行来自 Eclipse 中的 JUnit 测试时，它每次都会失败。我使用的是完全相同的数据和完全相同的反序列化代码。但是，当我从 JUnit 测试中运行它时，我得到以下异常：

com.amazonaws.SdkClientException: Unable to parse Json String.
    at com.amazonaws.util.json.Jackson.fromJsonString(Jackson.java:66)
    at com.myapp.filters.test.AbstractResourceFilterCriteriaTest.testMeetsCriteria_Fail(AbstractResourceFilterCriteriaTest.java:166)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access[=11=]0(ParentRunner.java:58)
    at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    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:678)
    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: com.fasterxml.jackson.databind.JsonMappingException: Conflicting setter definitions for property "instanceType": com.amazonaws.services.ec2.model.Instance#setInstanceType(1 params) vs com.amazonaws.services.ec2.model.Instance#setInstanceType(1 params)
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:269)
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:244)
    at com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:142)
    at com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:461)
    at com.fasterxml.jackson.databind.ObjectMapper._findRootDeserializer(ObjectMapper.java:3838)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3732)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2726)
    at com.amazonaws.util.json.Jackson.fromJsonString(Jackson.java:64)
    ... 26 more
Caused by: java.lang.IllegalArgumentException: Conflicting setter definitions for property "instanceType": com.amazonaws.services.ec2.model.Instance#setInstanceType(1 params) vs com.amazonaws.services.ec2.model.Instance#setInstanceType(1 params)
    at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder.getSetter(POJOPropertyBuilder.java:300)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.filterBeanProps(BeanDeserializerFactory.java:619)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.addBeanProps(BeanDeserializerFactory.java:515)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.buildBeanDeserializer(BeanDeserializerFactory.java:256)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.createBeanDeserializer(BeanDeserializerFactory.java:169)
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer2(DeserializerCache.java:403)
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:352)
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:264)
    ... 33 more

知道这里到底出了什么问题吗？为什么它在主应用程序代码中工作得很好，但在运行作为 JUnit 测试时却失败了？由于我不拥有 Instance 对象（它是亚马逊 SDK 的一部分），所以我无法修改任何 Jackson 注释。知道如何在我的单元测试中解决这个问题吗？

Answer 1

我想说您可能在测试和生产之间遇到 SDK 的版本问题。查看他们的源代码 class:

https://github.com/aws/aws-sdk-java/blob/master/aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/Instance.java

他们似乎在两个 setter 之一上对 jackson 进行了注释，指定这是用于序列化/反序列化的那个。这是最新版本，我没有回溯历史查看旧版本是否缺少此版本。

Jackson："Conflicting setter definitions for property" 在 JUnit 测试中

Jackson: "Conflicting setter definitions for property" in JUnit Tests

eclipse

junit

json

jackson

aws-java-sdk