在Java Web中使用Jena Api ...未知异常 [英] Using Jena Api in Java Web... Unknown Exception
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问题描述
有人在Java Web应用程序中使用Jena时遇到过此异常吗?请帮助我..
Did anyone encountered this exception while using Jena in Java Web Application... Please Kindly help me ..
这是我的servlet代码
Here is my servlet code
package com.mycompany.servlet;
import java.io.IOException;
import java.util.Iterator;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.hp.hpl.jena.query.QueryExecution;
import com.hp.hpl.jena.query.QueryExecutionFactory;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.ontology.*;
/**
* Servlet implementation class GreetingServlet
*/
@WebServlet("/GreetingServlet")
public class GreetingServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public GreetingServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
String SOURCE ="file:E:\\healthcare.owl";
OntModel base = ModelFactory.createOntologyModel( OntModelSpec.OWL_MEM );
base.read( SOURCE );
for (Iterator<OntClass> i = base.listClasses(); i.hasNext(); )
{
OntClass c = i.next();
//System.out.println( "Class" + c.getLocalName());
}
}
}
例外是 HTTP状态500-
Exception is HTTP Status 500 -
类型异常报告
消息
description The server encountered an internal error () that prevented it from fulfilling this request.
例外
javax.servlet.ServletException: Error instantiating servlet class com.mycompany.servlet.GreetingServlet
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
java.lang.Thread.run(Unknown Source)
根本原因
java.lang.NoClassDefFoundError: com/hp/hpl/jena/rdf/model/Model
java.lang.Class.getDeclaredConstructors0(Native Method)
java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
java.lang.Class.getConstructor0(Unknown Source)
java.lang.Class.newInstance0(Unknown Source)
java.lang.Class.newInstance(Unknown Source)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
java.lang.Thread.run(Unknown Source)
根本原因
java.lang.ClassNotFoundException: com.hp.hpl.jena.rdf.model.Model
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
java.lang.Class.getDeclaredConstructors0(Native Method)
java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
java.lang.Class.getConstructor0(Unknown Source)
java.lang.Class.newInstance0(Unknown Source)
java.lang.Class.newInstance(Unknown Source)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
java.lang.Thread.run(Unknown Source)
note可以在Apache Tomcat/7.0.11日志中找到根本原因的完整堆栈跟踪.
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.11 logs.
推荐答案
root cause
java.lang.ClassNotFoundException: com.hp.hpl.jena.rdf.model.Model
这意味着tomcat找不到Jena库.确保在正确的位置放置所有正确的罐子.
That means that tomcat can't find the Jena libraries. Make sure you have all the right jars in the right place.
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