Hibernate + GWT異常

Question

我正在慢慢地使用GWT + Hibernate來解決我的代碼異常，我的服務器端類如下......

public class GreetingServiceImpl extends RemoteServiceServlet implements
    GreetingService {

public String greetServer(String input) throws IllegalArgumentException {
    // Verify that the input is valid. 
    if (!FieldVerifier.isValidName(input)) {
        // If the input is not valid, throw an IllegalArgumentException back to
        // the client.
        throw new IllegalArgumentException(
                "Name must be at least 4 characters long");
    }

    // Escape data from the client to avoid cross-site script vulnerabilities.
    input = escapeHtml(input);
    User user = new User();
    user.setFirstName(input);
    DaoFactory factory = new DaoFactory();
    try {
        factory.create(user);
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return "User : " + input + " added";
}

/**
 * Escape an html string. Escaping data received from the client helps to
 * prevent cross-site script vulnerabilities.
 * 
 * @param html the html string to escape
 * @return the escaped string
 */
private String escapeHtml(String html) {
    if (html == null) {
        return null;
    }
    return html.replaceAll("&", "&amp;").replaceAll("<", "&lt;")
            .replaceAll(">", "&gt;");
}

這會收到一個字符串，將用戶firstname設置為此字符串並將其提交給db，但是我收到以下錯誤...

[ERROR] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String com.behaviour.app.client.GreetingService.greetServer(java.lang.String) throws java.lang.IllegalArgumentException' threw an unexpected exception: java.lang.ExceptionInInitializerError
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:385)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:588)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    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$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58)
    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:122)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
    at org.mortbay.jetty.servlet.ServletHandler$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.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:351)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
    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)
Caused by: java.lang.ExceptionInInitializerError
    at com.behaviour.hibernate.HibernateUtil.<clinit>(HibernateUtil.java:21)
    at com.behaviour.hibernate.DaoFactory.create(DaoFactory.java:9)
    at com.behaviour.app.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
    ... 34 more
Caused by: java.lang.ExceptionInInitializerError
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
    at java.sql.DriverManager.getConnection(DriverManager.java:620)
    at java.sql.DriverManager.getConnection(DriverManager.java:169)
    at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:113)
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2863)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2859)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1870)
    at com.behaviour.hibernate.HibernateUtil.<clinit>(HibernateUtil.java:15)
    ... 42 more
Caused by: java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)
    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:393)
    at java.security.AccessController.checkPermission(AccessController.java:553)
    at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
    at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166)
    at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkAccess(DevAppServerFactory.java:191)
    at java.lang.ThreadGroup.checkAccess(ThreadGroup.java:315)
    at java.lang.Thread.init(Thread.java:353)
    at java.lang.Thread.<init>(Thread.java:437)
    at java.util.TimerThread.<init>(Timer.java:478)
    at java.util.Timer.<init>(Timer.java:100)
    at java.util.Timer.<init>(Timer.java:146)
    at com.mysql.jdbc.Connection.<clinit>(Connection.java:201)
    ... 51 more

我不確定如何處理這個問題。 涉及的課程如下......

public class HibernateUtil 
{
  private static final SessionFactory sessionFactory;

   static 
   {
    try 
      {
       // Create the SessionFactory from hibernate.cfg.xml
       sessionFactory = new Configuration().configure().buildSessionFactory();
       } 
       catch (Throwable ex)
       {
         // Make sure you log the exception, as it might be swallowed
         System.err.println("Initial SessionFactory creation failed." + ex);
         throw new ExceptionInInitializerError(ex);
       }
    }

    public static SessionFactory getSessionFactory()
    {
     return sessionFactory;
    }
 }

和

public class DaoFactory
{
   public void create(Object obj)throws Exception
   {
     Session session = HibernateUtil.getSessionFactory().getCurrentSession();
     session.beginTransaction();
     session.save(obj);
     session.getTransaction().commit();
   }
}

謝謝，

抱歉沒有真正解釋，但我是GWT和Hibernate的新手。

Answer 1

您似乎在Google App Engine的開發服務器中運行您的應用程序。

如果您的服務器應用程序是Google App Engine應用程序，則可能不會使用Hibernate。 在GAE應用程序中保留數據的唯一方法是使用App Engine DataStore。 App Engine開發服務器有一個安全管理器，可以復制在實際的Google App Engine服務器上執行的操作，並禁止MySQL驅動程序創建和修改線程組，如堆棧跟蹤所示。

如果您的服務器應用程序是旨在部署在標准Java EE應用程序服務器（Tomcat，Jetty，GlassFish等）中的傳統Web應用程序，則將其設置為Web應用程序並將其部署在其中一個服務器中。