GWT +冬眠集成：HSQLDialect类转换异常

Question

我配置GWT 2.4.0 +休眠4.x的

我使用利用数据传输对象（DTO），其集成策略继GWT教程： https://developers.google.com/web-toolkit/articles/using_gwt_with_hibernate

但是当我运行该项目作为Web应用程序（使用谷歌eclipse插件）时，抛出了这个异常：

引起：java.lang.NoClassDefFoundError：java.net.Socket是一个受限制的类。有关更多详细信息，请参阅Google App Engine开发人员指南。

完整例外：

Initial SessionFactory creation failed.java.lang.NoClassDefFoundError: java.net.Socket is a restricted class. Please see the Google App Engine developer's guide for more details. 
01/04/2012 22:11:39 com.google.appengine.tools.development.ApiProxyLocalImpl log 
GRAVE: javax.servlet.ServletContext log: Exception while dispatching incoming RPC call 
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String web.reg.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:60) 
    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.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:363) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at org.mortbay.jetty.Server.handle(Server.java:326) 
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) 
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) 
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 
Caused by: java.lang.ExceptionInInitializerError 
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:17) 
    at web.reg.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:36) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:104) 
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569) 
    ... 34 more 
Caused by: java.lang.NoClassDefFoundError: java.net.Socket is a restricted class. Please see the Google App Engine developer's guide for more details. 
    at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51) 
    at org.hsqldb.HsqlSocketFactory.createSocket(Unknown Source) 
    at org.hsqldb.HSQLClientConnection.openConnection(Unknown Source) 
    at org.hsqldb.HSQLClientConnection.initConnection(Unknown Source) 
    at org.hsqldb.HSQLClientConnection.<init>(Unknown Source) 
    at org.hsqldb.jdbc.jdbcConnection.<init>(Unknown Source) 
    at org.hsqldb.jdbcDriver.getConnection(Unknown Source) 
    at org.hsqldb.jdbcDriver.connect(Unknown Source) 
    at java.sql.DriverManager.getConnection(DriverManager.java:582) 
    at java.sql.DriverManager.getConnection(DriverManager.java:154) 
    at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:173) 
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcServicesImpl.java:242) 
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:117) 
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131) 
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71) 
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2273) 
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2269) 
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1738) 
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778) 
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:13) 

我读过在这个论坛：http://www.mail-archive.com/google-web-toolkit@googlegroups.com/msg44312.html 我应该取消对日食“使用谷歌应用程序引擎”选项，并且还删除此谷歌应用程序引擎的罐子引用。

好吧，我做到了。

但是当我运行通过Eclipse插件GWT的，当我启动应用程序，并发送一些数据存储在服务器上抛出此异常：

Caused by: org.hibernate.HibernateException: Could not instantiate dialect class 
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:82) 
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:64) 
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:170) 
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131) 
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71) 
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2273) 
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2269) 
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1738) 
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778) 
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:13) 
    ... 28 more 
Caused by: java.lang.ClassCastException: org.hibernate.dialect.HSQLDialect cannot be cast to org.hibernate.dialect.Dialect 
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:73) 

我的hibernate.cfg.xml是真的使用有机 org.hibernate.dialect.HSQLDialect

the .jar files I'm using are: 

on GWT structure: 


war/WEB-INF/lib: 
|- antlr-2.7.7.jar 
|- dom4j-1.6.1.jar 
|- gwt-servlet.jar 
|- hibernate-commons-annotations-4.0.1.Final.jar 
|- hibernate-core-4.1.1.Final.jar 
|- hibernate-entitymanager-4.1.1.Final.jar 
|- hibernate-jpa-2.0-api-1.0.1.Final.jar 
|- hsqldb.jar 
|- javassist-3.15.0-GA.jar 
|- jboss-logging-3.1.0.GA.jar 
|- jboss-transaction-api_1.1_spec-1.0.0.Final.jar 
|- jsr107cache-1.1.jar 

缺少什么：由酒店.hibernate.dialect.HSQLDialect？或者有什么我不应该放？

Answer 1

这是一个Jetty Classloader问题。我自己没有得到这个特定的错误，但是这个问题在Hibernate Bug Report中有详细描述。

Vladimir Konkov建议更改ClassLoaderServiceImpl.java以向构造函数传递null值应该可以解决此问题。

this.classClassLoader = new ClassLoader(null) { 
     @Override 
     protected Class<?> findClass(String name) throws ClassNotFoundException { 
      for (ClassLoader loader : classLoadingClassLoaders) { 
       try { 
        return loader.loadClass(name); 
       } 
       catch (Exception ignore) { 
       } 
      } 
      throw new ClassNotFoundException("Could not load requested class : " + name); 
     } 
}; 

Answer 2

我认为@Strelok是正确的，似乎你有兼容性问题之间的罐子HSQLDB和hibernate.4x。如果你已经从谷歌网站下载了集成gwt + hibernate的例子，最好检查一下这个例子使用的jar版本，并且你应该检查你是否添加了一些不兼容的jar。