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我正在使用GWT的類項目，雖然一切工作之前，我最近重構我的代碼，突然間我跑進入標題錯誤。我四處搜索，看起來GWTBridge問題是由兩個主要原因造成的：a）修正爲2.5.1的錯誤，或者b）嘗試從服務器調用客戶端代碼，反之亦然（classNotFoundException GWTBridge）。GWT錯誤：java.lang.NoClassDefFoundError：com /谷歌/ gwt /核心/客戶端/ GWTBridge
我正在使用GWT 2.5.1，我99％確定我沒有違反b），所以我很茫然。我簡直就是在重構時從工作版本複製粘貼代碼，所以我不確定問題來自哪裏。
我的直覺是，它可能與我在重構時創建的兩個靜態Singleton類有關。重構時的我的目標僅僅是讓RPC更不混亂，因爲它迫使我鏈接一堆異樣的調用，這使得我瘋狂。我基本上做的是創建兩個靜態的Singleton類（PageLoader和UserManager），它們的目的是進行異步調用並返回返回的任何OnSuccess，這樣在onModuleLoad中我可以進行連續的RPC調用而不必處理鏈接（例如，我可以只需進入UserManager.getInstance（）。isLoggedIn（），然後在稍後的RPC調用中使用返回的布爾值，而不必將該調用放入onSuccess函數中。我將這兩個類與我的Async類放在client.services中。
我不知道爲什麼這可能會導致一個問題，但我想不出別的。知道我是否在正確的軌道上？
我已經附加了下面的一個靜態類和部分返回的堆棧跟蹤。
的UserManager類
package com.google.gwt.sample.vendorcouver.client.services;
import com.google.gwt.core.client.GWT;
import com.google.gwt.sample.vendorcouver.client.user.VenUser;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
/*Singleton that simplifies making asynchronous calls to the server side.*/
public class UserManager {
private static UserManager UserManagerInstance = null;
private static LoginServiceAsync LoginServiceInstance = null;
private static VenUserServiceAsync VenUserServiceInstance = null;
private static boolean isLoggedIn = false;
private static boolean isAdmin = false;
private static String UserName = null;
public static UserManager getInstance()
{
if (UserManagerInstance == null)
{
UserManagerInstance = new UserManager();
LoginServiceInstance = GWT.create(LoginService.class);
VenUserServiceInstance = GWT.create(VenUserService.class);
}
return UserManagerInstance;
}
public boolean isLoggedIn()
{
LoginServiceInstance.isLoggedIn(new AsyncCallback<Boolean>() {
public void onFailure(Throwable error) {
Window.alert("Sorry, there seemed to be an error on the server side! You may be unable to log in.");
}
public void onSuccess(Boolean loggedInStatus) {
Window.alert("isLoggedIn is sucessful; will return" + loggedInStatus);
isLoggedIn = loggedInStatus;
}
});
return isLoggedIn;
}
堆棧跟蹤：
SEVERE: javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract boolean com.google.gwt.sample.vendorcouver.client.services.LoginService.isLoggedIn()' threw an unexpected exception: java.lang.NoClassDefFoundError: com/google/gwt/core/client/GWTBridge
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:389)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:579)
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$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at org.mortbay.jetty.servlet.ServletHandler$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$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
at org.mortbay.jetty.servlet.ServletHandler$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$ApiProxyHandler.handle(JettyContainerService.java:487)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$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.NoClassDefFoundError: com/google/gwt/core/client/GWTBridge
at com.google.gwt.user.client.Window.<clinit>(Window.java:504)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
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 com.google.gwt.sample.vendorcouver.server.LoginServiceImpl.isLoggedIn(LoginServiceImpl.java:17)
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.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:115)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:561)
... 40 more
Caused by: java.lang.ClassNotFoundException: com.google.gwt.core.client.GWTBridge
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:216)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 52 more
啊，你是對的！我沒有意識到這會是一個問題。你可以擴展你的第二個評論嗎？我不明白爲什麼isLoggedIn（）總是返回false。爲什麼RPC調用是異步的，首先它總是返回false？ – aquariuz
當你第一次調用'isLoggedIn（）'時，你發出一個異步的RPC請求，並且由於它是異步的，控制在響應返回之前返回'isLoggedIn（）'，所以'return isLoggedIn'返回初始值'isLoggedIn'，它是'false'。然後幾毫秒後，響應從服務器返回並更新'isLoggedIn'（假設爲'true'）。下一次調用'isLoggedIn（）'，你創建一個新的RPC並返回'isLoggedIn'的_previous_值（即'true'），然後幾毫秒後響應到達並更新'isLoggedIn'。 –