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我在外部服务器上有两台虚拟机。 VM1是Tomcat服务器，VM2是MySQL服务器。我在tomcat服务器上有一个web应用程序，我可以通过在我的家用计算机的浏览器中输入ip来访问该应用程序，以便它可以正常工作。无法获得外部MySQL服务器以使用Java Web应用程序+ Hibernate。 （无法构建EntityManagerFactory）
例如，如果IP到VM1是111.22.33.44，那么我就可以从任何地方输入这一点，并能够访问网页：http://111.22.33.44:8080/WebApplication1
但在那之后，我尝试在我的web应用程序登录，我得到一个异常：
javax.persistence.PersistenceException：[PersistenceUnit：WebApplication1PU]无法建立的EntityManagerFactory
我只能假设，这已经是与我的外部数据库服务器。
的persistence.xml（XXXX为VM2的IP）：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="WebApplication1PU" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>bo.User</class>
<class>bo.LogMessage</class>
<class>bo.PrivateMessage</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="hibernate.connection.username" value="root"/>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.connection.password" value="root"/>
<property name="hibernate.connection.url" value="jdbc:mysql://x.x.x.x:3306/community"/>
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/>
</properties>
</persistence-unit>
</persistence>
我试图做修复它：对VM1 IP +用户名MySQL服务器上
- 授予权限。
- 嗯，这是我现在所能记得的，我会编辑这个。
我也可以在堆栈跟踪中编辑，如果有帮助的话。
另外：两个虚拟机有完全不同的IP地址。我读了一些关于将RESOURCE_LOCAL更改为JTA的方法，是否可以解决任何问题？
编辑1 traceroute给了2行（跳？） 我评论了my.conf文件中的绑定127.0.0.1行。仍然不起作用。 尝试在Web应用程序的主页上登录时出现异常。 （堆栈跟踪）：
javax.faces.el.EvaluationException: javax.persistence.PersistenceException: [PersistenceUnit: WebApplication1PU] Unable to build EntityManagerFactory
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:185)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:151)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:269)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:679)
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: WebApplication1PU] Unable to build EntityManagerFactory
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:677)
at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:126)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:51)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:33)
at db.UserDB.getUserByUsername(UserDB.java:49)
at bo.UserHandler.UserLogin(UserHandler.java:30)
at ui.UserBean.login(UserBean.java:56)
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 org.apache.el.parser.AstValue.invoke(AstValue.java:262)
at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
... 24 more
Caused by: org.hibernate.HibernateException: Hibernate Dialect must be explicitly set
at org.hibernate.dialect.DialectFactory.determineDialect(DialectFactory.java:57)
at org.hibernate.dialect.DialectFactory.buildDialect(DialectFactory.java:39)
at org.hibernate.cfg.SettingsFactory.determineDialect(SettingsFactory.java:426)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:128)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2009)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1292)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:669)
... 38 more
编辑2 netstat的-anltp |对VM2（MySQL服务器）
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN -
tcp6 0 0 :::22 :::* LISTEN -
tcp6 0 0 ::1:631 :::* LISTEN -
编辑3 netstat的-anltp grep的 “听” | grep的“听”上VM2（MySQL服务器） 现在听的外部连接到MySQL（要做到这一点请参见本指南的第4步：link
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN -
tcp6 0 0 :::22 :::* LISTEN -
tcp6 0 0 ::1:631 :::* LISTEN -
我很抱歉，如果这很难理解，我只是很累这个东西整天工作。 – 2012-01-12 20:18:46
您是否能够使用其他数据库运行应用程序？ Hibernate无法构建EntityManagerFactory可能意味着很多事情：错误的类映射，无法连接，防火墙阻止端口等... – clmarquart 2012-01-12 20:47:10
如果您确定已授予“VM1 ip + username”的mysql访问权限， VM2上的mysql侦听端口3306并接受非本地主机连接？ – 2012-01-12 20:48:57