java.lang.LinkageError：加载器约束冲突：解析方法“org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor时

java.lang.LinkageError: loader constraint violation: when resolving method "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor

提问by My-Name-Is

A JSF web application tries to retrieve resource from a Java EE web service. The JSF web app works fine. Since I added the Http client source to retrive web service resources the JBoss instance claims about:

JSF Web 应用程序尝试从 Java EE Web 服务检索资源。JSF Web 应用程序运行良好。由于我添加了 Http 客户端源来检索 Web 服务资源，因此 JBoss 实例声称：

15:29:47,689 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (http--0.0.0.0-443-1) Error Rendering View[/index.xhtml]: javax.el.ELException: /surfaceParts/sideBarLeft.xhtml @14,79 value="#{categories.cats}": java.lang.LinkageError: loader constraint violation: when resolving method "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, at/fhj/ase/ssl/SSLClientHelper, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, org/jboss/resteasy/client/core/executors/ApacheHttpClient4Executor, have different Class objects for the type xecutors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V used in the signature
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIData.getValue(UIData.java:731) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIData.getDataModel(UIData.java:1798) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIData.setRowIndex(UIData.java:473) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIData.encodeBegin(UIData.java:1118) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1777) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:125) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:489) [jbossweb-7.0.13.Final.jar:]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Unknown Source) [rt.jar:1.7.0_25]
Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, at/fhj/ase/ssl/SSLClientHelper, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, org/jboss/resteasy/client/core/executors/ApacheHttpClient4Executor, have different Class objects for the type xecutors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V used in the signature
    at at.fhj.ase.ssl.SSLClientHelper.getSSLClientRequest(SSLClientHelper.java:71) [classes:]
    at at.fhj.ase.beans.Categories.getCats(Categories.java:39) [classes:]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_25]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:302) [jboss-el-api_2.2_spec-1.0.0.Final.jar:1.0.0.Final]
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at org.apache.el.parser.AstValue.getValue(AstValue.java:169) [jbossweb-7.0.13.Final.jar:]
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189) [jbossweb-7.0.13.Final.jar:]
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) [jsf-impl-2.1.7-jbossorg-2.jar:]
    ... 36 more

I'm pretty sure that the HttpClient source is fine, since it's the same what is used at the web service side for JUnit tests.

我很确定 HttpClient 源是好的，因为它与在 Web 服务端用于 JUnit 测试的源相同。

ProjectSetup:The web service is deployed on JBoss AS7.1 (works fine so far) The JSF web client is deployed on the same JBoss instance. Both are started via Eclipse. The Deployment assembly for of the JSF web client looks like:

ProjectSetup：Web 服务部署在 JBoss AS7.1 上（目前工作正常） JSF Web 客户端部署在同一个 JBoss 实例上。两者都是通过 Eclipse 启动的。JSF Web 客户端的部署程序集如下所示：

I assume that the linkage error is caused by the external (BuildPath & DeploymentAssembly) added apache http client library. But how do I resolve this?

我假设链接错误是由外部（BuildPath & DeploymentAssembly）添加的 apache http 客户端库引起的。但是我该如何解决这个问题？

Please tell me if you need further details. I am very grateful for any help!

如果您需要更多详细信息，请告诉我。我非常感谢任何帮助！

采纳答案by CoolBeans

The reason why you are seeing the error is because RestEasy has a dependency on httpclient jars which is provided as a jboss module. The version you provided is conflicting with the one provided by JBoss .

您看到错误的原因是 RestEasy 依赖于作为 jboss 模块提供的 httpclient jar。您提供的版本与 JBoss 提供的版本冲突。

Why do you need to package the HTTPClient jars with your web app? Is it for some rest client call? In that case you should use RestEasy which is the default JAX-RS implementation on JBoss AS7. It will be a better framework to use for that purpose.

为什么需要将 HTTPClient jar 与 Web 应用程序一起打包？是为了一些休息的客户电话吗？在这种情况下，您应该使用 RestEasy，它是 JBoss AS7 上的默认 JAX-RS 实现。这将是一个更好的框架用于该目的。

Your other option is to add a dependency on the org.apache.httpcomponentsmodule in your WEB-INF\jboss-deployment-structure.xmland remove the http-client jars from WEB-INF\lib.

您的另一个选择是org.apache.httpcomponents在您的模块中添加依赖项，WEB-INF\jboss-deployment-structure.xml并从WEB-INF\lib.