Tomcat中的OpenCV出现UnsatisfiedLinkError [英] UnsatisfiedLinkError with OpenCV in Tomcat

问题描述

首先，我有一个在主要方法中运行的OpenCV的基本示例. 但是，如果我在Spring Web Controller中使用OpenCV，则会引发错误.

First of all, I have a basic example of OpenCV running in a main method. However, if I use OpenCV in a Spring Web Controller, an error is thrown.

在STS(Spring Tool Suite)的 Tomcat 服务器中运行以下代码时，出现UnsatisfiedLinkError异常，并将问题归结为以下代码:

I am getting an UnsatisfiedLinkError when running the following code inside a Tomcat Server, within STS (Spring Tool Suite), and have boiled the problem down to the following code:

System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
CascadeClassifier cascadeClassifier = new CascadeClassifier();

服务器和主"应用程序的运行配置都包含指向OpenCV DLL的VM参数:

The run configurations of both the server and the "main" application contain the VM Arguments pointing to the OpenCV DLLs:

-Djava.library.path="C:\opencv\build\java\x64;C:\opencv\build\x64\vc10\bin"

作为参考，我还包括了以下堆栈跟踪的相关位:

For reference, I have also included the pertinent bits of the stacktrace below:

org.springframework.web.util.NestedServletException: Handler processing failed;
nested exception is
java.lang.UnsatisfiedLinkError: org.opencv.objdetect.CascadeClassifier.CascadeClassifier_0()J
...
Caused by: java.lang.UnsatisfiedLinkError:
org.opencv.objdetect.CascadeClassifier.CascadeClassifier_0()J
    at org.opencv.objdetect.CascadeClassifier.CascadeClassifier_0(Native Method)
    at org.opencv.objdetect.CascadeClassifier.<init>(CascadeClassifier.java:38)
    at com.immersion.test.controllers.SimpleController.createClassifier(SimpleController.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

注意:我已经阅读了几个 StackOverflow线程，其中缺少UnsatisfiedLinkError的主要原因System.loadLibrary(Core.NATIVE_LIBRARY_NAME)呼叫.显然这里不是这种情况，因为它是在引发异常的上方调用的.

Note: I have read in several StackOverflow threads that the main cause of the UnsatisfiedLinkError is the missing System.loadLibrary(Core.NATIVE_LIBRARY_NAME) call. This is clearly not the case here, since it is being called just above where the exception is thrown.

推荐答案

事实证明，用于在STS/Eclipse中启动Tomcat服务器的默认运行配置实际上只是Tomcat的启动器. 这意味着添加到Tomcat运行配置"的任何VM Args都不会传输到实际的Tomcat实例.

It turns out that the default run configuration to start a Tomcat server within STS/Eclipse is essentially just a launcher for Tomcat. This means that any VM Args that are added to the Tomcat 'run configuration' will not be transferred to the actual Tomcat instance.

在Tomcat目录中的tcruntime-instance.bat中查找(这最终创建了tomcat Java实例)，我们可以看到，只需将我们想要的VM Args添加到JAVA_OPTS环境变量中，这些dll就可以使用了.到Tomcat.

On looking in tcruntime-instance.bat within the Tomcat directory (this is what ends up creating the tomcat java instance), we can see that simply by adding our intended VM Args to the JAVA_OPTS environment variable, the dlls will be available to Tomcat.

TL; DR:

所以.只需将OpenCV二进制文件的位置添加到您的JAVA_OPTS环境变量中:

So.. Simply add the the locations of the OpenCV binaries to your JAVA_OPTS environment variable:

-Djava.library.path="C:\opencv\build\java\x64;C:\opencv\build\x64\vc10\bin"

有关为Tomcat设置JAVA_OPTS的更多信息，请参见此这样的问题.

For more information on setting JAVA_OPTS for Tomcat, see this SO question.

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