尝试在junit中模拟X500Principal时出现LinkageError答案

【问题标题】：LinkageError when try to mock X500Principal in junit尝试在junit中模拟X500Principal时出现LinkageError
【发布时间】：2016-06-09 12:04:44
【问题描述】：

我正在尝试通过使用 PowerMockRunner 模拟 java.security.cert.X509Certificate、javax.security.auth.x500.X500Principal 来编写测试用例。当我尝试为 X500Principal 导入类时，IDE 显示 2 个导入选项（javax.security.auth.x500.X500Principal、com.sun.security.auth.X500Principal）。我仍然使用了正确的导入它显示以下错误。另一个导入也被弃用了。

Exception in thread "main" java.lang.LinkageError: loader constraint violation: when resolving overridden method "$java.security.cert.X509Certificate$$EnhancerByMockitoWithCGLIB$$887d20cf.getSubjectX500Principal()Ljavax/security/auth/x500/X500Principal;" the class loader (instance of org/powermock/core/classloader/MockClassLoader) of the current class, $java/security/cert/X509Certificate$$EnhancerByMockitoWithCGLIB$$887d20cf, and its superclass loader (instance of <bootloader>), have different Class objects for the type javax/security/auth/x500/X500Principal used in the signature
    at sun.reflect.GeneratedSerializationConstructorAccessor13.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
    at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.newInstance(SunReflectionFactoryInstantiator.java:40)
    at org.objenesis.ObjenesisBase.newInstance(ObjenesisBase.java:59)
    at org.mockito.internal.creation.jmock.ClassImposterizer.createProxy(ClassImposterizer.java:128)
    at org.mockito.internal.creation.jmock.ClassImposterizer.imposterise(ClassImposterizer.java:63)
    at org.powermock.api.mockito.internal.mockcreation.MockCreator.createMethodInvocationControl(MockCreator.java:109)
    at org.powermock.api.mockito.internal.mockcreation.MockCreator.mock(MockCreator.java:57)
    at org.powermock.api.mockito.PowerMockito.mock(PowerMockito.java:203)
    at org.powermock.api.extension.listener.AnnotationEnabler.standardInject(AnnotationEnabler.java:106)
    at org.powermock.api.extension.listener.AnnotationEnabler.beforeTestMethod(AnnotationEnabler.java:54)
    at org.powermock.tests.utils.impl.PowerMockTestNotifierImpl.notifyBeforeTestMethod(PowerMockTestNotifierImpl.java:90)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:292)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:127)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:282)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:207)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:146)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:120)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:122)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:106)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
    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:483)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

Process finished with exit code 1

【问题讨论】：

查看导致此异常的 Java 代码会很有帮助。然而，根本问题是同一个类 (javax/security/auth/x500/X500Principal) 是由两个不同的类加载器加载的，正如错误消息所述，它与 Mockito 的工作方式有关（虽然我对 Mockito 不是特别熟练)

标签： java unit-testing junit powermock x509

【解决方案1】：

使用@PowerMockIgnore({"java.net.ssl", "javax.security.auth.x500.X500Principal"}) 发现它在 PowerMockRunner 本身中工作。我做错的事情是我只忽略了 X500Principal。

使用 MockitoJunitRunner 也可以正常工作，没有任何错误。

【讨论】：

我遇到了同样的错误。用 @PowerMockIgnore("javax.security.auth.x500.X500Principal") 注释我的测试类对我有用
@PowerMockIgnore({ "javax.management.*", "javax.net.ssl.*", "javax.crypto.*" }) 为我们工作。