如何使用 REFLECTION 或任何其他 API 在最终 class 中初始化私有变量？

Question

这可能听起来很尴尬，但我正在尝试在最终 class 中初始化一个私有变量。我已经做过很多次了，我知道使用 Reflection 效果很好，但我从来没有真正用最终的 class 做过。由于我无法实例化 class 我无法传递任何对象来设置变量，这就是我被卡住的地方。

决赛class

public final class LoggingHandler implements ILoggingHandler {

private Log generalLog; 

/**
 * @param log The general log.
 */
private void setGeneralLog(Log log) {
    generalLog = log;
}

/**
 * @return The general log.
 */
private Log getGeneralLog() {
    return generalLog;
}

JUnit

@Test
public void testSendDocuments() throws Exception {
    AppContext.setApplicationContext( applicationContext );
    IClientUserDto iClientUserDto = mock( IClientUserDto.class );

    DocusignRESTProvider docusignRestProvider = new DocusignRESTProvider();
    docusignRestProvider.setLoggingHandler( iloggingHandler );
    docusignRestProvider.setDocumentManager( iDocumentManager );
    docusignRestProvider.setConfiguration( iProviderConfiguration );
    docusignRestProvider.setManager( iManager );

    Field field = LoggingHandler.class.getDeclaredField( "generalLog" );
    field.setAccessible( true );
    field.set( new Object(), log );

    when( iTransformer.transformRequest( any( SendDocumentsTransformerArgs.class ) ) ).thenReturn( iTransformerResult );
    docusignRestProvider.sendDocuments( iClientUserDto, iDocumentSet );
}

log 是模拟对象。

堆栈跟踪：

java.lang.IllegalArgumentException: Can not set org.apache.commons.logging.Log field com.mercuryinsurance.esignature.common.logging.LoggingHandler.generalLog to java.lang.Object
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:164)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:168)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:55)
at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:75)
at java.lang.reflect.Field.set(Field.java:741)
at test.com.mercuryinsurance.esignature.integration.provider.docusign.rest.TestDocusignRESTProvider.testSendDocuments(TestDocusignRESTProvider.java:167)
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.internal.runners.TestMethod.invoke(TestMethod.java:66)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:310)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:86)
at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:94)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:294)
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:84)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:49)
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.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.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)

有人可以让我知道还有什么其他方法可以测试这种情况以及如何测试吗？

谢谢

Answer 1

您误用了 final class 的概念。 Final classes 可以被实例化，它们不能被继承。因此，在您的情况下 LoggingHandler 可以而且应该被实例化，除非它的构造函数是私有的。但是，如果它的构造函数是私有的 - 这样一个 class 实现接口的意义何在？

您应该为 Log 字段创建 public setter 和 getter，实例化一个 LoggingHandler 实例并在测试中传递一个模拟您的 Log 对象。您稍后可以对该模拟进行任何需要的验证。

如何使用 REFLECTION 或任何其他 API 在最终 class 中初始化私有变量？

How to initialize a private variable in a final class using REFLECTION or any other API?

java

reflection

junit

mockito

powermock