.dll 是否已经加载到另一个类加载器中? [英] .dll already loaded in another classloader?

问题描述

我有一个在 Tomcat 3.2.1 下运行的 web 应用程序，需要进行 JNI 调用以便访问遗留 C++ 代码中的数据和方法.加载了一个 servlet在webapp 的启动，作为其 init 方法的一部分，导致一个数据集特定于要加载到 C++ 数据中的 webapp 实例结构.

I have a webapp running under Tomcat 3.2.1 that needs to make JNI calls in order to access data and methods in legacy C++ code. A servlet is loaded on startup of the webapp that, as part of its init method, causes a data set specific to that webapp instance to be loaded into the C++ data structures.

此 servlet 的 Java 代码包含以下内容:

This Java code for this servlet contains the following:

static
{
    try {
        System.loadLibrary("JCoreImpl");
        System.out.println("JCoreImpl loaded");
        m_bLibraryLoaded = true;
    } catch (UnsatisfiedLinkError e) {
        m_bLibraryLoaded = false;
        System.out.println("JCoreImpl NOT loaded " + e);
    }
}

如果只有一个 web 应用程序(我们称之为webapps/aaa").

Things work fine if there is only one webapp (let's call it "webapps/aaa").

如果我有第二个与 webapps/aaa 相同的 webapp(webapps/bbb")除了 C++ 数据结构中使用的数据集，然后是 webapps/aaa启动很好，但是当 webapps/bbb 启动时我收到一个错误陈述那个:

If I have a second webapp ("webapps/bbb") that is identical to webapps/aaa except for the data set used in the C++ data structures, then webapps/aaa starts up just fine, but when webapps/bbb is started I get an error stating that:

JCoreImpl NOT loaded java.lang.UnsatisfiedLinkError: Native Library
E:WebStationinDebugJCoreImpl.dll already loaded in another classloader

我需要为每个我的本地库创建一个单独的实例webapps，因为每个实例都需要包含唯一的数据特定的网络应用程序.我已经搜索了邮件档案并阅读了Craig McLanahan 解释类加载器层次结构的电子邮件.但是我有无法找到任何特定于加载唯一实例的每个 Web 应用程序的本机库.

I need to have a separate instance of the native library for each of my webapps as each instance needs to contain data that is unique to that particular webapp. I have searched through the mail archives and read emails by Craig McLanahan explaining the classloader hierarchy. But I have not been able to find anything specific to loading a unique instance of a native library for each webapp.

推荐答案

不能两次加载同一个本机库.

You can't load the same native library twice.

将类放在<tomcat>/lib/下的jar文件中，它将在所有战争中共享.

Put the class in a jar file under <tomcat>/lib/, it will be shared over all wars.

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