Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack.

本文详细解析了在使用Struts2框架时遇到的无法找到输入流错误的原因,并提供了相应的解决办法。通过修改配置参数,解决了Action中输入流名称不匹配的问题。

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1、错误描述

八月 14, 2015 4:22:45 下午 com.opensymphony.xwork2.util.logging.jdk.JdkLogger error
严重: Exception occurred during processing request: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
	at org.apache.struts2.dispatcher.StreamResult.doExecute(StreamResult.java:237)
	at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:369)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:273)
	at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
	at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

八月 14, 2015 4:22:45 下午 com.opensymphony.xwork2.util.logging.jdk.JdkLogger error
严重: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
八月 14, 2015 4:22:45 下午 com.opensymphony.xwork2.util.logging.jdk.JdkLogger error
严重: Exception occurred during processing request: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
	at org.apache.struts2.dispatcher.StreamResult.doExecute(StreamResult.java:237)
	at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:369)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:273)
	at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
	at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

2、错误原因

<action name="download" class="com.you.mail.action.DownloadAction">
			<result name="success" type="stream">
				<param name="contentType">
					application/vnd.ms-powerpoint
				</param>
				<param name="contentDisposition">
					filename="ceshi.ppt"
				</param>
				<param name="inputName">downloadFile</param>
			</result>
		</action>

3、解决办法

在下载Action中,配置参数没有downloadFile,导致报错;查看Action,参数名为fileName,将downloadFile修改成fileName

<think>好的,我现在需要解决用户提到的JNI报错问题:“JNI DETECTED ERROR IN APPLICATION: can't call java.io.InputStream in call to CallObjectMethodV”。首先,我得理解这个错误的具体原因和可能的情况。 用户可能在JNI代码中调用了某个Java对象的CallObjectMethodV方法,但参数类型不匹配。错误信息指出无法调用java.io.InputStream,可能是在调用某个返回InputStream的方法时出了问题。常见的情况可能有以下几种: 1. **方法签名错误**:JNI调用方法时,需要准确的方法签名。如果方法签名与实际Java方法不匹配,JNI会找不到正确的方法,导致调用失败。比如,假设Java方法返回的是InputStream,但签名写成了其他类型,如Ljava/lang/Object;,或者参数类型不正确,就会出问题。 2. **对象引用问题**:可能调用方法的对象不是正确的Java实例。比如,如果获取实例的方法有误,或者对象已经被回收,导致调用时对象不存在,进而引发错误。 3. **JNIEnv的使用错误**:在多线程环境下,JNIEnv是每个线程独有的,如果在错误的线程中使用,或者JNIEnv指针被错误使用,可能导致问题。 接下来,我需要逐步分析可能的解决步骤。首先,用户应该检查他们调用的方法签名是否正确。可以使用javap -s命令获取准确的签名。例如,假设Java类中有一个方法public InputStream getInputStream(String path),其签名应该是类似(Ljava/lang/String;)Ljava/io/InputStream;。用户需要确保在JNI代码中使用的是这个正确的签名。 然后,检查在JNI中是否正确获取了方法ID。例如,调用GetMethodID时,传入的类对象、方法名和签名是否正确。如果方法名拼写错误,或者类名不正确(如使用了错误的包路径),GetMethodID会返回NULL,这时候继续调用CallObjectMethodV就会导致崩溃。 另外,需要确认调用CallObjectMethodV时传入的对象是否是该方法所属的实例。例如,如果调用的是一个实例方法,必须确保传入的jobject参数是该类的有效实例;如果是静态方法,则需要使用CallStaticObjectMethod,并且传入jclass而不是jobject。 还有可能是在调用方法时参数不匹配,例如方法需要参数但未正确传入,或者参数类型不对。例如,方法需要一个jstring参数,但实际传入的是其他类型,或者没有正确转换本地字符串到jstring。 另外,考虑JNI异常处理的问题。在调用JNI方法时,如果有异常抛出,应该检查异常并处理,否则后续的JNI调用可能会导致未定义行为。用户可以在调用JNI方法后使用ExceptionCheck或ExceptionOccurred来检查是否有异常发生,并及时处理。 可能还需要检查是否在正确的上下文中使用JNIEnv。比如,在异步回调或者不同线程中调用JNI时,需要确保每个线程都正确获取了JNIEnv指针,否则会导致错误。 总结一下,解决步骤可能包括: 1. 检查方法签名是否正确,使用javap工具确认。 2. 确保正确获取方法ID,并且方法ID不为NULL。 3. 确认调用方法的对象实例是否正确有效。 4. 检查参数类型和数量是否与方法签名匹配。 5. 处理JNI异常,避免异常未捕获导致后续错误。 6. 确保在多线程环境下正确使用JNIEnv。 此外,用户可能需要注意内存管理问题,比如局部引用是否溢出,或者没有正确释放局部引用导致的内存泄漏,这些也可能间接引发问题。不过这个错误更可能直接与方法调用相关。 最后,建议用户提供一个代码片段,这样能更具体地分析问题所在。例如,展示JNI中获取方法ID和调用CallObjectMethodV的部分代码,以便检查是否有明显的错误。</think>--- ### 逐步解析:`JNI DETECTED ERROR IN APPLICATION: can't call java.io.InputStream in call to CallObjectMethodV` 这个错误通常是由于 **JNI代码调用Java方法时,方法签名不匹配** 或 **对象类型错误** 导致的。以下是具体原因和解决方案: --- #### 1. **检查方法签名是否正确** - **问题根源**:JNI调用Java方法时,需通过方法签名(Method Signature)匹配目标方法。如果签名错误,JNI会调用错误的方法,导致类型不兼容。 - **解决方法**: 1. 使用 `javap -s` 获取方法的准确签名。例如,对于以下Java方法: ```java public class MyClass { public InputStream getInputStream(String path) { ... } } ``` 执行 `javap -s MyClass`,输出结果中会显示签名: ``` descriptor: (Ljava/lang/String;)Ljava/io/InputStream; ``` 2. 在JNI代码中使用此签名: ```c jmethodID methodID = env->GetMethodID( cls, "getInputStream", "(Ljava/lang/String;)Ljava/io/InputStream;" ); ``` --- #### 2. **确认方法ID获取成功** - **问题根源**:如果 `GetMethodID()` 返回 `NULL`,调用 `CallObjectMethodV()` 会崩溃。 - **解决方法**: - 检查方法名和签名是否与Java代码完全一致(包括大小写)。 - 确保 `jclass` 参数 `cls` 是目标类的正确引用(例如通过 `FindClass("com/example/MyClass")` 获取)。 --- #### 3. **验证对象实例有效性** - **问题根源**:如果调用方法的Java对象(`jobject`)无效(如已被释放或未正确初始化),会导致错误。 - **解决方法**: - 确保 `jobject` 是通过合法途径获得的实例(如构造函数调用或其他方法返回)。 - 使用 `env->IsSameObject(obj, NULL)` 检查对象是否为 `null`。 --- #### 4. **参数类型匹配** - **问题根源**:调用方法时传入的参数类型与签名不匹配,例如: - Java方法需要一个 `String`,但JNI传入了一个 `jint`。 - 参数数量错误(如方法需要1个参数,但传入了0个)。 - **解决方法**: - 对照签名检查参数类型和数量: ```c // 正确示例:传入一个jstring参数 jstring path = env->NewStringUTF("/data/file.txt"); jobject inputStream = env->CallObjectMethod( obj, methodID, path ); ``` --- #### 5. **处理JNI异常** - **问题根源**:Java代码可能抛出未处理的异常,导致后续JNI调用失败。 - **解决方法**: - 在关键JNI操作后检查异常: ```c if (env->ExceptionCheck()) { env->ExceptionDescribe(); // 打印异常信息 env->ExceptionClear(); // 清除异常 return; } ``` --- ### 示例代码对比(错误 vs 正确) #### ❌ 错误代码 ```c // 假设方法签名错误写成了 (I)Ljava/io/InputStream; jmethodID methodID = env->GetMethodID(cls, "getInputStream", "(I)Ljava/io/InputStream;"); jobject inputStream = env->CallObjectMethod(obj, methodID, 123); // 传入int而非String ``` #### ✅ 正确代码 ```c // 正确签名 (Ljava/lang/String;)Ljava/io/InputStream; jmethodID methodID = env->GetMethodID(cls, "getInputStream", "(Ljava/lang/String;)Ljava/io/InputStream;"); jstring path = env->NewStringUTF("/data/file.txt"); jobject inputStream = env->CallObjectMethod(obj, methodID, path); ``` --- ### 总结 - **关键点**:方法签名、对象有效性、参数匹配、异常处理。 - **调试建议**:使用 `adb logcat` 查看完整堆栈,定位JNI调用位置。 - **扩展阅读**:参考Oracle官方JNI文档中的 [Type Signatures](https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/types.html#type_signatures)。
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