我设法从帖子stackoverflow post about GWT获取提示来解决此问题。该帖子告诉我，JDBC不应该在客户端，而应在服务器端。
我正在尝试创建一个简单的Web应用程序，使用GWT RPC和Hibernate，MySql＆amp; eclipse IDE。我已经有一个简单版本的hibernate程序运行＆amp;现在我正在尝试使用GWT RPC做同样的事情。
虽然在使用带有RPC的hibernate时可能存在某些不同的做法。首先，我必须将jar / libs添加到war / web.inf / lib add中，然后再将它们添加到classpath中，同时我在src中创建了一个简单的文件夹，将所有jars / library放到那个＆amp;然后添加到classpath中的简单hibernate应用程序。继续，编译器然后引发了关于cfg.xml＆amp;的不可用性的错误。映射hibernate文件包中的文件（包含pojo文件）。我把它们移到src文件夹＆amp;错误消失了。但现在错误是关于会话创建。这次将Util文件移动到src不起作用。
这是我项目的目录结构：
src
hbm.xml
cfg.xml
hibDomain(hibernate package)
rppctest.client (GWT package)
rppctest.server (GWT package)
我在Windows 7上使用MySQL。 以下是错误消息＆amp;我的代码。
错误
94 [btpool0-2] INFO org.hibernate.cfg.Environment - Hibernate 3.3.1.GA
126 [btpool0-2] INFO org.hibernate.cfg.Environment - hibernate.properties not found
173 [btpool0-2] INFO org.hibernate.cfg.Environment - Bytecode provider name : javassist
282 [btpool0-2] INFO org.hibernate.cfg.Environment - using JDK 1.4 java.sql.Timestamp handling
751 [btpool0-2] INFO org.hibernate.cfg.Configuration - configuring from resource: /hibernate.cfg.xml
751 [btpool0-2] INFO org.hibernate.cfg.Configuration - Configuration resource: /hibernate.cfg.xml
3657 [btpool0-2] INFO org.hibernate.cfg.Configuration - Reading mappings from resource : user.hbm.xml
4018 [btpool0-2] INFO org.hibernate.cfg.HbmBinder - Mapping class: com.hib.User -> users
Initial SessionFactory creation failed.org.hibernate.InvalidMappingException: Could not parse mapping document from resource user.hbm.xml
Starting Jetty on port 8888
[WARN] Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String rpctest.client.RpctestService.addUser(java.lang.String,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:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: java.lang.ExceptionInInitializerError
at hibDomain.HibernateUtil.buildSessionFactory(HibernateUtil.java:16)
at hibDomain.HibernateUtil.<clinit>(HibernateUtil.java:7)
at rpctest.server.RpctestServiceImpl.addUser(RpctestServiceImpl.java:19)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
... 22 more
Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from resource user.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:602)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1621)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1589)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1568)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1542)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1462)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1448)
at hibDomain.HibernateUtil.buildSessionFactory(HibernateUtil.java:11)
... 29 more
Caused by: org.hibernate.MappingException: class com.hib.User not found while looking for property: firstName
at org.hibernate.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:97)
at org.hibernate.mapping.SimpleValue.setTypeUsingReflection(SimpleValue.java:302)
at org.hibernate.cfg.HbmBinder.createProperty(HbmBinder.java:2193)
at org.hibernate.cfg.HbmBinder.createClassProperties(HbmBinder.java:2170)
at org.hibernate.cfg.HbmBinder.createClassProperties(HbmBinder.java:2060)
at org.hibernate.cfg.HbmBinder.bindRootPersistentClassCommonValues(HbmBinder.java:381)
at org.hibernate.cfg.HbmBinder.bindRootClass(HbmBinder.java:295)
at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:166)
at org.hibernate.cfg.Configuration.add(Configuration.java:702)
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:537)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:599)
... 36 more
Caused by: java.lang.ClassNotFoundException: com.hib.User
at java.lang.ClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:352)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:337)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.hibernate.util.ReflectHelper.classForName(ReflectHelper.java:123)
at org.hibernate.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:93)
... 46 more
[ERROR] 500 - POST /rpctest/testService (127.0.0.1) 57 bytes
Request headers
Accept: */*
X-GWT-Permutation: HostedMode
X-GWT-Module-Base: http://127.0.0.1:8888/rpctest/
Content-Type: text/x-gwt-rpc; charset=utf-8
Referer: http://127.0.0.1:8888/Rpctest.html?gwt.codesvr=127.0.0.1:9997
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
Host: 127.0.0.1:8888
Content-Length: 168
Connection: Keep-Alive
Cache-Control: no-cache
Response headers
Content-Type: text/plain
入口点类
package rpctest.client;
import rpctest.shared.FieldVerifier;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyUpEvent;
import com.google.gwt.event.dom.client.KeyUpHandler;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;
/**
* Entry point classes define <code>onModuleLoad()</code>.
*/
public class Rpctest implements EntryPoint {
final TextBox firstName = new TextBox();
final TextBox lastName = new TextBox();
final Button ans = new Button("Add User");
final Label label1 = new Label("First Name");
final Label label2 = new Label("Last Name");
//final Label errorLabel = new Label();
private VerticalPanel mainpanel = new VerticalPanel();
private HorizontalPanel addpanel1 = new HorizontalPanel();
private HorizontalPanel addpanel2 = new HorizontalPanel();
private final RpctestServiceAsync calNumbers = GWT
.create(RpctestService.class);
/**
* This is the entry point method.
*/
public void onModuleLoad() {
addpanel1.add(label1);
addpanel1.add(firstName);
addpanel2.add(label2);
addpanel2.add(lastName);
mainpanel.add(addpanel1);
mainpanel.add(addpanel2);
mainpanel.add(ans);
ans.addClickHandler(new ClickHandler() {
@Override
public void onClick(ClickEvent event) {
String name1 = firstName.getValue();
String name2 = lastName.getValue();
calNumbers.addUser(name1,name2,
new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
// Show the RPC error message to the user
Window.alert("check your inputs");
}
@Override
public void onSuccess(String result) {
// TODO Auto-generated method stub
Window.alert("User is ->"+result);
}
});}
});
// We can add style names to widgets
//sendButton.addStyleName("sendButton");
// Add the nameField and sendButton to the RootPanel
// Use RootPanel.get() to get the entire body element
/*RootPanel.get("nameFieldContainer").add(nameField);
*
RootPanel.get("sendButtonContainer").add(sendButton);
RootPanel.get("errorLabelContainer").add(errorLabel);*/
RootPanel.get().add(mainpanel);
}
}
接口
package rpctest.client;
import com.google.gwt.user.client.rpc.RemoteService;
import com.google.gwt.user.client.rpc.RemoteServiceRelativePath;
@RemoteServiceRelativePath("testService")
public interface RpctestService extends RemoteService {
String addUser(String firstName,String lastName) throws IllegalArgumentException;
}
package rpctest.client;
import com.google.gwt.user.client.rpc.AsyncCallback;
public interface RpctestServiceAsync {
void addUser(String firstName, String lastName,
AsyncCallback<String> callback);
}
实施
package rpctest.server;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
import hibDomain.HibernateUtil;
import org.hibernate.Session;
import org.hibernate.Transaction;
import hibDomain.User;
import hibDomain.Task;
import rpctest.client.RpctestService;
public class RpctestServiceImpl extends RemoteServiceServlet implements RpctestService {
public String addUser(String name1, String name2)
throws IllegalArgumentException {
Transaction trns = null;
Session session = HibernateUtil.getSessionFactory().openSession();
try {
trns = session.beginTransaction();
User user = new User();
user.setFirstName(name1);
user.setLastName(name2);
session.save(user);
session.getTransaction().commit();
} catch (RuntimeException e) {
if(trns != null){
trns.rollback();
}
e.printStackTrace();
} finally{
session.flush();
session.close();
}
return name1;
}
}
Hibernate文件
package hibDomain;
public class User {
private Integer id;
private String firstName;
private String lastName;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
映射文件
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.hib.User" table="users" >
<id name="id" type="int" column="id" >
<generator class="native"/>
</id>
<property name="firstName">
<column name="first_name" />
</property>
<property name="lastName">
<column name="last_name"/>
</property>
</class>
</hibernate-mapping>
cfg文件
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/userdata</property>
<property name="connection.username">root</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<!-- Mapping files -->
<mapping resource="user.hbm.xml"/>
<mapping resource="task.hbm.xml"/>
</session-factory>
</hibernate-configuration>
的Util
package hibDomain;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return 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;
}
}
答案 0 :(得分：0)
您的hibernate类文件（User）位于“hibDomain”包中。你正在制作的地图是“com.hib.User”。将此更改为hibDomain.User，可能工作。