创建一个转换器以使用 ByteBuddy 从代理添加 class

Question

我正在尝试从使用 ByteBuddy 实现的代理加载类。 我在代理中定义了一个 class 并希望将其加载到目标程序中。 这是我的变压器的样子：

public class ClassLoaderTransformer implements AgentBuilder.Transformer {
    private final Class<?> targetClass;

    public ClassLoaderTransformer(Class<?> targetClass) {
        this.targetClass = targetClass;
    }

    @Override
    public DynamicType.Builder<?> transform(DynamicType.Builder<?> builder, TypeDescription typeDescription, ClassLoader classLoader, JavaModule module) {
        try {
            final Class<?> aClass = Class.forName(typeDescription.getName());

            resolveClassLoadingStrategy(aClass).load(classLoader, singletonMap(
                    new TypeDescription.ForLoadedType(targetClass),
                    ClassFileLocator.ForClassLoader.read(targetClass)
            ));
        } catch (Exception e){
            System.out.println("Something went terribly wrong: " + e.getMessage());
        }

        return builder;
    }

    private static ClassLoadingStrategy<ClassLoader> resolveClassLoadingStrategy(Class<?> targetClass) throws IllegalAccessException {
        if ( !ClassInjector.UsingLookup.isAvailable() ) {
            return new ClassLoadingStrategy.ForUnsafeInjection(targetClass.getProtectionDomain() );
        }

        MethodHandles.Lookup lookup = MethodHandles.lookup();
        MethodHandles.Lookup privateLookup = MethodHandles.privateLookupIn(targetClass, lookup);

        return ClassLoadingStrategy.UsingLookup.of( privateLookup );
    }
}

但是，此代码不起作用。 它抛出以下错误：

tech.ikora.seleniumagent.helpers.SourcePageFetcher must be defined in the same package as org.openqa.selenium.remote.RemoteWebDriver

堆栈跟踪如下所示：

java.lang.IllegalArgumentException: tech.ikora.seleniumagent.helpers.SourcePageFetcher must be defined in the same package as org.openqa.selenium.remote.RemoteWebDriver
        at net.bytebuddy.dynamic.loading.ClassInjector$UsingLookup.injectRaw(ClassInjector.java:1414)
        at net.bytebuddy.dynamic.loading.ClassInjector$AbstractBase.inject(ClassInjector.java:110)
        at net.bytebuddy.dynamic.loading.ClassLoadingStrategy$UsingLookup.load(ClassLoadingStrategy.java:492)
        at tech.ikora.seleniumagent.ClassLoaderTransformer.transform(ClassLoaderTransformer.java:27)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.doTransform(AgentBuilder.java:10364)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:10302)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.access$1600(AgentBuilder.java:10068)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:10761)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:10699)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:389)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:10258)
        at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$ByteBuddy$ModuleSupport.transform(Unknown Source)
        at java.instrument/sun.instrument.TransformerManager.transform(TransformerManager.java:188)
        at java.instrument/sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:563)
        at java.base/java.lang.ClassLoader.defineClass1(Native Method)
        at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
        at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
        at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:515)
        at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:423)
        at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:417)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:689)
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:416)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        at org.apache.maven.surefire.booter.IsolatedClassLoader.loadClass(IsolatedClassLoader.java:97)
        at java.base/java.lang.ClassLoader.defineClass1(Native Method)
        at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
        at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
        at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:515)
        at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:423)
        at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:417)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:689)
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:416)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        at org.apache.maven.surefire.booter.IsolatedClassLoader.loadClass(IsolatedClassLoader.java:97)
        at base.BaseTest.setup(BaseTest.java:31)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:567)
        at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:132)
        at org.testng.internal.MethodInvocationHelper.invokeMethodConsideringTimeout(MethodInvocationHelper.java:61)
        at org.testng.internal.ConfigInvoker.invokeConfigurationMethod(ConfigInvoker.java:366)
        at org.testng.internal.ConfigInvoker.invokeConfigurations(ConfigInvoker.java:320)
        at org.testng.internal.TestMethodWorker.invokeBeforeClassMethods(TestMethodWorker.java:176)
        at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:122)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
        at org.testng.TestRunner.privateRun(TestRunner.java:764)
        at org.testng.TestRunner.run(TestRunner.java:585)
        at org.testng.SuiteRunner.runTest(SuiteRunner.java:384)
        at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:378)
        at org.testng.SuiteRunner.privateRun(SuiteRunner.java:337)
        at org.testng.SuiteRunner.run(SuiteRunner.java:286)
        at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)
        at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)
        at org.testng.TestNG.runSuitesSequentially(TestNG.java:1218)
        at org.testng.TestNG.runSuitesLocally(TestNG.java:1140)
        at org.testng.TestNG.runSuites(TestNG.java:1069)
        at org.testng.TestNG.run(TestNG.java:1037)
        at org.apache.maven.surefire.testng.TestNGExecutor.run(TestNGExecutor.java:77)
        at org.apache.maven.surefire.testng.TestNGDirectoryTestSuite.executeMulti(TestNGDirectoryTestSuite.java:159)
        at org.apache.maven.surefire.testng.TestNGDirectoryTestSuite.execute(TestNGDirectoryTestSuite.java:99)
        at org.apache.maven.surefire.testng.TestNGProvider.invoke(TestNGProvider.java:106)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:567)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
        at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
        at org.apache.maven.plugin.surefire.InPluginVMSurefireStarter.runSuitesInProcess(InPluginVMSurefireStarter.java:80)
        at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeProvider(AbstractSurefireMojo.java:724)
        at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeAllProviders(AbstractSurefireMojo.java:682)
        at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeAfterPreconditionsChecked(AbstractSurefireMojo.java:648)
        at org.apache.maven.plugin.surefire.AbstractSurefireMojo.execute(AbstractSurefireMojo.java:586)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:210)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:156)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:148)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:56)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:305)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:192)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:105)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:957)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:289)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:193)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:567)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:282)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:225)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:406)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:347)

在此示例中， SourcePageFetcher是 targetClass， RemoveWebDriver是TypeDescription提供的 class。

这个 class 加载器的目标是加载类，这些类将成为我为检测我的代码而创建的一些Advice的助手。 我应该尝试以其他方式使用ClassInjector吗？ 还是我以错误的方式看到了问题，还是应该只使用另一个 ClassLoadingStrategy？

Answer 1

正如错误消息所示：查找仅允许您在指定查找的 class 的包中定义类。 如果 package 与您的不同：

tech.ikora.seleniumagent.helpers 
org.openqa.selenium.remote

JVM 不允许这样做。 但是，您也可以从代理使用UsingUnsafe策略，因为Instrumentation实例可以授予您对 JVM 内部的访问权限。 否则，您需要将您的注入连接到右侧 package 中的 class。

请注意，您可以直接使用ClassInjector而不是使用ClassLoadingStrategy 。

Answer 2

按照@RafaelWinterhalter 的建议，对我有用的解决方案是将ClassInjector 与UsingUnsafe 一起使用。 这导致以下工作代码：

public class ClassLoaderTransformer implements AgentBuilder.Transformer {
    private final Class<?> targetClass;

    public ClassLoaderTransformer(Class<?> targetClass) {
        this.targetClass = targetClass;
    }

    @Override
    public DynamicType.Builder<?> transform(DynamicType.Builder<?> builder, TypeDescription typeDescription, ClassLoader classLoader, JavaModule module) {
        try {
            ClassInjector.UsingUnsafe.ofBootLoader().inject(singletonMap(
                    new TypeDescription.ForLoadedType(targetClass),
                    ClassFileLocator.ForClassLoader.read(targetClass)
            ));
        } catch (Throwable e){
            System.out.println("Something went terribly wrong: " + e.getMessage());
        }

        return builder;
    }
}

请注意，在这种情况下，class 正在引导 class 加载程序中加载，因此我们应该尽量保持加载的类尽可能简单。 此外，这里加载的类似乎无法访问由子 class 加载器加载的类，所以我不得不再次将这些类保持在最低限度。