在java Web应用程序中加载外部库 [英] Load external library in java web application

问题描述

我的方案如下：

我有一个部署到servlet容器的WebApp.war。此WebApp.war在WEB-INF / lib中包含以下库：

I have a WebApp.war that is deployed to a servlet container. This WebApp.war contains in WEB-INF/lib the following libraries:

• lib_a.jar


• lib_b.jar

我有另一个库，比如lib_vendor.jar，我无法在WebApp / WEB-INF / lib中部署因为许可问题所以我让我们的客户在安装应用程序后在tomcat / lib中复制这个库。但由于lib_vendor.jar需要在Web应用程序类加载器中加载lib_a.jar和lib_b.jar，因此我无法使用lib_vendor.jar。

I have one other library, say lib_vendor.jar, that I cannot deploy within WebApp/WEB-INF/lib because of licensing issues so I let our customers to copy this library in tomcat/lib after application installation. But since lib_vendor.jar requires lib_a.jar and lib_b.jar that are loaded in the web application class loader, I cannot use lib_vendor.jar.

如何加载外部库（不在WEB-INF / lib中）在Web应用程序的同一个类加载器中？

How can I load an external library (not in WEB-INF/lib) in the same classloader of a web application?

推荐答案

因为您使用的是Tomcat ，您可以利用 VirtualWebappLoader 。

Since you are using Tomcat, you could leverage the VirtualWebappLoader.

添加 META-INF / context.xml whith

<?xml version="1.0" encoding="UTF-8"?>
<Context path="/somepath/myapp">
    <Loader className="org.apache.catalina.loader.VirtualWebappLoader"
              virtualClasspath="/somedir/*.jar"/>
</Context>

还要记住virtualClasspath属性必须是绝对路径，如下面的注释中所述。

Remember also that the virtualClasspath attribute must be a absolute path, as correctly stated in the comment below.

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