Spring WebApp中使用Elasticsearch客户端时出现链接错误

我在尝试将 Elasticsearch java 客户端包含在我的 Web 应用程序中时遇到问题。我有所需的依赖项，并且我正在初始化/销毁 Spring bean 中创建客户端（作为一个简单的测试），如下所示：

    @Override
public void afterPropertiesSet() throws Exception {
    try {
        client = new TransportClient();
        InetSocketTransportAddress addr = new InetSocketTransportAddress("localhost", 9300);
        ((TransportClient) client).addTransportAddress(addr);
    } 
    catch(Exception e){
        System.out.println(e.toString());
    }
}

相应的destroy()将关闭客户端。

一切看起来都正常，上下文启动也很好，但是当访问 JSP 时，我收到以下异常：

SEVERE: Servlet.service() for servlet [jsp] in context with path [/Fountain] threw           exception [Filter execution threw an exception] with root cause
java.lang.LinkageError: loader constraint violation in interface itable initialization: when resolving method "javax.servlet.ServletResponseWrapper.getOutputStream()Ljavax/servlet/ServletOutputStream;" the class loader (instance of org/apache/catalina/loader/WebappClassLoader) of the current class, javax/servlet/ServletResponseWrapper, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for interface javax/servlet/ServletResponse have different Class objects for the type vlet/ServletOutputStream; used in the signature
    at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:186)
at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:181)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)

Jan 10, 2014 10:44:46 AM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.LinkageError: loader constraint violation: when resolving method "javax.servlet.jsp.JspFactory.getPageContext(Ljavax/servlet/Servlet;Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/jsp/ajaxerror_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspFactory, have different Class objects for the type t/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext; used in the signature
at org.apache.jsp.jsp.ajaxerror_jsp._jspService(ajaxerror_jsp.java:59)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:489)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:467)
at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:412)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:201)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)

Jan 10, 2014 10:44:46 AM org.apache.catalina.core.StandardHostValve custom
SEVERE: Exception Processing ErrorPage[exceptionType=java.lang.Throwable,      location=/jsp/ajaxerror.jsp]
org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.LinkageError: loader constraint violation: when resolving method "javax.servlet.jsp.JspFactory.getPageContext(Ljavax/servlet/Servlet;Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/jsp/ajaxerror_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspFactory, have different Class objects for the type t/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext; used in the signature
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:489)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:467)
at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:412)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:201)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.servlet.ServletException: java.lang.LinkageError: loader constraint violation: when resolving method    "javax.servlet.jsp.JspFactory.getPageContext(Ljavax/servlet/Servlet;Ljavax/servlet/ServletR equest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/jsp/ajaxerror_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspFactory, have different Class objects for the type t/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext; used in the signature
at org.apache.jsp.jsp.ajaxerror_jsp._jspService(ajaxerror_jsp.java:130)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
... 22 more
Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "javax.servlet.jsp.JspFactory.getPageContext(Ljavax/servlet/Servlet;Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/jsp/ajaxerror_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspFactory, have different Class objects for the type t/ServletRequest;Ljavax/servlet/ServletResponse;Ljava/lang/String;ZIZ)Ljavax/servlet/jsp/PageContext; used in the signature
at org.apache.jsp.jsp.ajaxerror_jsp._jspService(ajaxerror_jsp.java:59)
... 25 more

如果没有这个，上下文就会启动并正确地为 JSP 提供服务。

有谁知道可能是什么原因造成的？我假设 elasticsearch 客户端正在使用网络应用程序所需的类，但在不同的类加载器中实例化它。

我尝试使用 ImmutableSettings 显式设置弹性搜索使用的类加载器，但这似乎没有任何区别：

    ClassLoader contextClassLoader = thread.getContextClassLoader();
    try {
        //thread.setContextClassLoader(ClassLoader.getSystemClassLoader());
        Settings s = ImmutableSettings.settingsBuilder()
                .classLoader(contextClassLoader)
                .build();   

任何帮助，将不胜感激！谢谢！

好的，成功解决了这个问题：

获取 tomcat 'common' 类加载器的引用并将其传递给 Elasticsearch 客户端：

ClassLoader contextClassLoader = thread.getContextClassLoader();
try {
        Settings settings = ImmutableSettings.settingsBuilder().classLoader(contextClassLoader.getParent()).build();            
        client = new TransportClient(settings);

这样做的一个副作用是，names.txt 文件必须从 elasticSearch jar 移动到“公共”类路径上的某个位置。

我仍然没有弄清楚为什么这个问题会影响我的特定堆栈而不是其他堆栈，但目标是这样做并在此处更新。