java - JDO - Google Web 应用程序中的 java.lang.NoClassDefFoundError

Question

我正在尝试做一个Google Web Application。Java我有一个名为 的 servlet Get.java，一个EMF.java负责存储的 servlet 和一个 Java Bean Person.java，.

获取.java：

package no.nordnes;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.jdo.PersistenceManager;
import javax.jdo.Query;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;



public class Get extends HttpServlet {
    /**
     * 
     */
    private static final long serialVersionUID = -3326161721516453994L;

    @SuppressWarnings("unchecked")
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {
        List<Person> persons = new ArrayList<Person>();


        PersistenceManager pm = PMF.get().getPersistenceManager();
        Query qur = pm.newQuery("Select * FROM " + Person.class.getName());
        persons = (List<Person>) qur.execute();

        HttpSession ses = req.getSession();
        ses.setAttribute("persons", persons);   
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String navn = req.getParameter("name");
        String alder = req.getParameter("age");
        Person per = new Person(navn,alder);
        PersistenceManager pm = PMF.get().getPersistenceManager();

        pm.makePersistent(per);
        pm.close();

        resp.sendRedirect("index.jsp");
    }
}

PMF.java：

package no.nordnes;


import javax.jdo.JDOHelper;
import javax.jdo.PersistenceManagerFactory;

public class PMF {


    private static final PersistenceManagerFactory pmfInstance = 
            JDOHelper.getPersistenceManagerFactory("transactions-optional");

    private PMF(){

    }

    public static PersistenceManagerFactory get(){

        return pmfInstance; 
    }
}

人.java：

package no.nordnes;


import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;


@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Person {

    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Long id;

    @Persistent
    private String name;
    @Persistent
    private String age;

    public Person(String name,String age){
        this.age = age;
        this.name = name;       
    }


    public String getName() {
        return name;
    }


    public void setName(String name) {
        this.name = name;
    }


    public String getAge() {
        return age;
    }


    public void setAge(String age) {
        this.age = age;
    } 
}

我的jdoconfig.xml样子是这样的：

<?xml version="1.0" encoding="utf-8"?>
<jdoconfig xmlns="http://java.sun.com/xml/ns/jdo/jdoconfig"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="http://java.sun.com/xml/ns/jdo/jdoconfig">

    <persistence-manager-factory name="transactions-optional">
        <property name="javax.jdo.PersistenceManagerFactoryClass"
            value="org.datanucleus.api.jdo.JDOPersistenceManagerFactory"/>
        <property name="javax.jdo.option.ConnectionURL" value="appengine"/>
        <property name="javax.jdo.option.NontransactionalRead" value="true"/>
        <property name="javax.jdo.option.NontransactionalWrite" value="true"/>
        <property name="javax.jdo.option.RetainValues" value="true"/>
        <property name="datanucleus.appengine.autoCreateDatastoreTxns" value="true"/>
        <property name="datanucleus.appengine.singletonPMFForName" value="true"/>
    </persistence-manager-factory>
</jdoconfig>

当我运行时doGet-method，我得到了这个错误：

HTTP ERROR 500

Problem accessing /Get. Reason:

    Could not initialize class no.nordnes.PMF
Caused by:

java.lang.NoClassDefFoundError: Could not initialize class no.nordnes.PMF
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:186)
    at com.google.appengine.tools.development.agent.runtime.RuntimeHelper.checkRestricted(RuntimeHelper.java:70)
    at com.google.appengine.tools.development.agent.runtime.Runtime.checkRestricted(Runtime.java:64)
    at no.nordnes.Get.doGet(Get.java:28)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.DevAppServerServersFilter.doDirectRequest(DevAppServerServersFilter.java:369)
    at com.google.appengine.tools.development.DevAppServerServersFilter.doDirectServerRequest(DevAppServerServersFilter.java:352)
    at com.google.appengine.tools.development.DevAppServerServersFilter.doFilter(DevAppServerServersFilter.java:115)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:97)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:438)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
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当我尝试该doPost方法时，我得到几乎相同的错误

我不知道为什么会这样。