如何在命令行上使用-javaagent来设置Spring和Tomcat的加载时织法 [英] how to setup load-time weaving with Spring and Tomcat WITHOUT using the -javaagent on the command line

问题描述

我正在使用Spring 3.2.9，Tomcat 6.0.44

I am using Spring 3.2.9, Tomcat 6.0.44

我正在尝试将应用程序的Spring工具提供程序(例如spring-instrumentation.jar)配置为在Tomcat上部署时进行加载时编织.

I am trying to configure my application's Spring instrumentation provider (e.g. spring-instrumentation.jar) for load-time weaving, when it is deployed on Tomcat.

我有一个要求不要使用: 在命令行上"-javaagent:/path/path/spring-instrument.jar"进行配置.

I have a requirement to NOT use: "-javaagent:/path/path/spring-instrument.jar" on the command line to do the configuration.

我已阅读到可以通过修改< Context>配置Spring工具.应用程序的Tomcat配置的元素(在Tomcat的server.xml或Web应用程序的context.xml中).添加适当的< Context> server.xml的元素导致我的应用程序被正确配置为与Spring的工具提供程序一起运行.将其添加到context.xml(请参见下文)不会导致工作设置正常.

I've read that I can configure the Spring instrumentation by modifying the <Context> element of my application's Tomcat configuration (in either Tomcat's server.xml or my web app's context.xml). Adding the appropriate <Context> element to the server.xml results in my application being correctly configured to run with Spring's instrumentation provider. Adding it to the context.xml (see below) does NOT result in a working setup.

我有一个META-INF/aop.xml文件，看起来像这样:

I have a META-INF/aop.xml file, looks like this:

    <aspectj>
        <weaver options="-verbose -showWeaveInfo -debug">
            <include within="com.mv.xx.services..*"/>
            <exclude within="com.mv.xx.aop..*"/>
        </weaver>
        <aspects>
            <aspect name="com.mv.xx.aop.MyAspect"/>
        </aspects>
    </aspectj>

我还通过将其添加到我的Spring上下文配置中来指定要使用加载时编织:

I also specify that I want to use load-time weaving by adding this to my Spring context config:

 <context:load-time-weaver />

然后将这个jar添加到我的应用程序的类路径中: spring-instrument-tomcat.jar

And I add this jar to my application's classpath: spring-instrument-tomcat.jar

我尝试过的内容:

启动Tomcat时，如果我使用-javaagent参数像这样在命令行上标识spring-instrument.jar的位置:

When starting Tomcat, If I identify the location of the spring-instrument.jar on the command line using the -javaagent parameter like this:

-javaagent:/path/path2/spring-instrument-3.2.9.RELEASE.jar

一切正常.

接下来，我从命令行中删除了"-javaagent:/path/path2/spring-instrument-3.2.9.RELEASE.jar". 在Tomcat的server.xml文件(位于$ CATALINE_HOME/conf中)中，我添加了一个< Context> < Host>元素的元素元素，像这样:

Next I removed "-javaagent:/path/path2/spring-instrument-3.2.9.RELEASE.jar" from the command line. In Tomcat's server.xml file (located in $CATALINE_HOME/conf), I added a a <Context> element to the <Host> element, like this:

<Context path="/myApp" docBase="myApp">
    <Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"/>
</Context>

使用此配置，所有行为均正常运行.但是我有一个要求不要修改Tomcat的server.xml，因为我无法控制server.xml(DevOps可以，并且不愿对其进行修改).

With this configuration everything behaves properly. However I have a requirement to not modify Tomcat's server.xml, since I don't have control over the server.xml (DevOps does, and is reluctant to modify it).

接下来，我删除了< Context> Tomcat的server.xml中的元素. 根据

Next I removed the <Context> element from Tomcat's server.xml. According to the Spring docs, I can add a /META-INF/context.xml to my webapp, and put the <Context> element that used to be in Tomcat's server.xml into the context.xml, like so:

        <Context>
            <Context path="/myApp" docBase="myApp">
                <Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"/>
            </Context>
        </Context>

但是，当我重新启动Tomcat时，我在日志中收到一条错误消息，内容为:

However when I restart Tomcat, I get an error message in the logs saying:

    SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.context.weaving.AspectJWeavingEnabler#0': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loadTimeWeaver': Initialization of bean failed; nested exception is java.lang.IllegalStateException: ClassLoader [org.apache.catalina.loader.WebappClassLoader] does NOT provide an 'addTransformer(ClassFileTransformer)' method. Specify a custom LoadTimeWeaver or start your Java virtual machine with Spring's agent: -javaagent:org.springframework.instrument.jar

深入研究之后，我读到一些建议，建议修改Spring配置中的<context:load-time-weaver/>元素，如下所示:

After digging around, I read something that suggested that I modify the <context:load-time-weaver/> element in my Spring config, like this:

        <context:load-time-weaver weaver-class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />

然后将包含InstrumentationLoadTimeWeaver.class的jar添加到我的类路径中.

And add the jar containing InstrumentationLoadTimeWeaver.class to my classpath.

但是，当我这样做时，我会在日志中收到以下错误消息:

However when I do that, I get this error message in the logs:

        SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
        java.lang.IllegalStateException: Must start with Java agent to use InstrumentationLoadTimeWeaver. See Spring documentation.
    etc....

任何人都可以解释如何在命令行中使用-javaagent来设置Spring和Tomcat的加载时织法，而无需修改server.xml吗?

Can anyone explain how to setup load-time weaving with Spring and Tomcat WITHOUT using the -javaagent on the command line, and WITHOUT modifying the server.xml?

推荐答案

这是我设法使用的代码，用于删除您提到的异常. 基本上，您必须实现LoadTimeWeavingConfigurer并重写方法getLoadTimeWeaver().

This is the code that I managed to use in order to removed the exception that you mentioned. Basically you have to implement the LoadTimeWeavingConfigurer and override the method getLoadTimeWeaver().

@Configuration
@ComponentScan(basePackages = "org.myproject")
@EnableAspectJAutoProxy
@EnableSpringConfigured
@EnableLoadTimeWeaving(aspectjWeaving = EnableLoadTimeWeaving.AspectJWeaving.AUTODETECT)
public class Config implements LoadTimeWeavingConfigurer {

    @Override
    public LoadTimeWeaver getLoadTimeWeaver() {
        return new ReflectiveLoadTimeWeaver();
    }

    @Bean
    public InstrumentationLoadTimeWeaver loadTimeWeaver()  throws Throwable {
        InstrumentationLoadTimeWeaver loadTimeWeaver = new InstrumentationLoadTimeWeaver();
        return loadTimeWeaver;
    }

}

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