Tomcat自定义classLoader

时间：2018-10-10 08:13:52

标签： tomcat classloader

我试图将tomcat切换到我的自定义类加载器，但出现了一些我无法理解的异常。 这是我的步骤： 在“ apache-tomcat-9.0.12 \ conf \ context.xml”中添加了字符串：

<Loader className="com.example.CustomClassLoader"/>

创建下一个课程：

package com.example;

import org.apache.catalina.loader.WebappClassLoader;

public class CustomClassLoader extends WebappClassLoader {
    static
    {
        System.out.println("mylog static init");
    }


    public CustomClassLoader() {
        super();
        System.err.println("mylog constructor");
    }

    public CustomClassLoader(ClassLoader parent) {
        super(parent);
        System.err.println("mylog constructor + " + parent);
    }
}

使用Maven将其构建到cl.jar中，然后将其放入apache-tomcat-9.0.12 \ lib目录中。

所以日志是：

mylog static init
mylog constructor
mylog constructor
10-Oct-2018 14:55:15.474 SEVERE [RMI TCP Connection(3)-127.0.0.1] org.apache.tomcat.util.digester.Digester.endElement End event threw exception
 java.lang.IllegalArgumentException: argument type mismatch
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:373)
    at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:145)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:944)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:609)
    at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1339)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2784)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1439)
    at org.apache.catalina.startup.ContextConfig.processContextConfig(ContextConfig.java:527)
    at org.apache.catalina.startup.ContextConfig.contextConfig(ContextConfig.java:465)
    at org.apache.catalina.startup.ContextConfig.init(ContextConfig.java:728)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:310)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
    at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:424)
    at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:137)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:173)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:743)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:719)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
    at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1737)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:457)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:406)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
    at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
    at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
    at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
    at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

10-Oct-2018 14:56:08.388 SEVERE [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.startup.ContextConfig.processContextConfig Parse error in context.xml for [/platez]
 org.xml.sax.SAXParseException; systemId: file:/C:/Users/Sergey/.IntelliJIdea2018.1/system/tomcat/Unnamed_softlogictest/conf/context.xml; lineNumber: 26; columnNumber: 53; Error at (26, 53) : argument type mismatch
    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:1862)
    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:1894)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:947)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:609)
    at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1339)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2784)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1439)
    at org.apache.catalina.startup.ContextConfig.processContextConfig(ContextConfig.java:527)
    at org.apache.catalina.startup.ContextConfig.contextConfig(ContextConfig.java:465)
    at org.apache.catalina.startup.ContextConfig.init(ContextConfig.java:728)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:310)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
    at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:424)
    at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:137)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:173)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:743)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:719)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
    at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1737)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:457)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:406)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
    at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
    at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
    at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
    at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:373)
    at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:145)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:944)
    ... 62 more

10-Oct-2018 14:56:26.995 SEVERE [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.startup.ContextConfig.processContextConfig Occurred at line [26] column [53]
  1. 我清楚地知道tomcat成功加载了我的自定义类加载器，因为我在日志中看到了初始化行。

  2. 问题未与我的类加载器连接，因为当我将加载器声明更改为：

    Loader className =“ org.apache.catalina.loader.WebappClassLoader”

我仍然看到相同的异常。 我在做什么错了？

1 个答案:

答案 0 :(得分：0)

我发现了问题。 Tomcat期望此xml中的org.apache.catalina.Loader实现为 IS WebappLoader，而不是WebappClassLoaderBase，WebappClassLoader，ParallelWebappClassLoader。因此，我应该扩展WebappLoader以便实现我的自定义类加载器逻辑。

也许还有另一个xml arg可以插入WebappClassLoaderBase继承者，但我在文档中看不到

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