我正在构建一个登录应用程序。每次单击按钮后，我都会收到Umbrella Exception......无法找到根本原因。我提供代码和错误列表。请向我提供修复程序。使用GWT-RPC
<小时/>客户端 1.VinLog.java
package com.login.vinayak.client;
import com.google.gwt.core.client.EntryPoint;
public class VinLog implements EntryPoint {
private GreetingServiceAsync GreetingService = (GreetingServiceAsync) GWT.create(GreetingService.class);
public void onModuleLoad() {
GWT.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
public void onUncaughtException(Throwable e) {
Window.alert("uncaught: " +e.getMessage());
Window.alert("uncaught: " + e.getMessage());
String s = buildStackTrace(e, "RuntimeExceotion:\n");
Window.alert(s);
e.printStackTrace();
System.out.println(e.getCause());
}
});
RootPanel rootPanel = RootPanel.get();
SimplePanel simplePanel = new SimplePanel();
rootPanel.add(simplePanel, 0, 0);
simplePanel.setSize("450px", "19px");
Label lblLoginForm = new Label("LOGIN");
lblLoginForm.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
simplePanel.setWidget(lblLoginForm);
lblLoginForm.setSize("544px", "41px");
Label lblUserName = new Label("User Name");
rootPanel.add(lblUserName, 10, 124);
Label lblPassword = new Label("Password");
rootPanel.add(lblPassword, 10, 183);
final TextBox textBox = new TextBox();
textBox.setAlignment(TextAlignment.CENTER);
rootPanel.add(textBox, 112, 114);
textBox.setSize("139px", "18px");
final PasswordTextBox passwordTextBox = new PasswordTextBox();
rootPanel.add(passwordTextBox, 112, 173);
passwordTextBox.setSize("139px", "18px");
Button btnClickToEnter = new Button("Click to Enter");
btnClickToEnter.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
String j=textBox.getText();
String k=passwordTextBox.getText();
GreetingService.loginuser(j, k, new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
Window.alert("welcome");
}
public void onSuccess(String result) {
Window.alert("try again");
}
});
}
});
rootPanel.add(btnClickToEnter, 10, 229);
final ListBox comboBox = new ListBox();
comboBox.addChangeHandler(new ChangeHandler() {
public void onChange(ChangeEvent event) {
Object ob=comboBox.getElement();
if(ob=="Guest") {
Window.alert("Username and Passowrd is: Guest007");
}
}
});
comboBox.addItem("User");
comboBox.addItem("Admin");
comboBox.addItem("Guest");
rootPanel.add(comboBox, 10, 51);
comboBox.setSize("85px", "22px");
Image image = new Image("home.gif");
rootPanel.add(image, 310, 98);
image.setSize("182px", "155px");
}
protected String buildStackTrace(Throwable t, String log) {
if (t != null) {
log += t.getClass().toString();
log += t.getMessage();
StackTraceElement[] stackTrace = t.getStackTrace();
if (stackTrace != null) {
StringBuffer trace = new StringBuffer();
for (int i = 0; i < stackTrace.length; i++) {
trace.append(stackTrace[i].getClassName() + "." + stackTrace[i].getMethodName() + "("
+ stackTrace[i].getFileName() + ":" + stackTrace[i].getLineNumber());
}
log += trace.toString();
}
Throwable cause = t.getCause();
if (cause != null && cause != t) {
log += buildStackTrace(cause, "CausedBy:\n");
}
}
return log;
}
}
2.GreetingService.java
package com.login.vinayak.client;
import com.google.gwt.user.client.rpc.RemoteService;
import com.google.gwt.user.client.rpc.RemoteServiceRelativePath;
@SuppressWarnings("unused")
public interface GreetingService extends RemoteService {
public String loginuser(String username, String password);
}
3.GreetinServiceAsync.java
package com.login.vinayak.client;
import com.google.gwt.user.client.rpc.AsyncCallback;
public interface GreetingServiceAsync {
public void loginuser(String username, String password, AsyncCallback<String> callback);
}
服务器端 ==> GreetingServiceImpl.java
package com.login.vinayak.server;
import com.login.vinayak.client.GreetingService;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
import java.sql.DriverManager;
import java.sql.ResultSet;
import com.google.gwt.dev.generator.ast.Statement;
public class GreetingServiceImpl extends RemoteServiceServlet implements GreetingService{
private static final long serialVersionUID = 1L;
public String loginuser(String username,String password) {
try {
java.sql.Connection con = null;
Class.forName("org.hsqldb.jdbcDriver");
con = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/", "SA", "");
Statement st=(Statement) con.createStatement();
ResultSet rs=((java.sql.Statement) st).executeQuery("select username,password from lgfrm");
String user=rs.getString(1);
String pass=rs.getString(2);
boolean b1=username.equals(user);
boolean b2= password.equals(pass);
if(b1==b2==true) {
return "success";
}
}
catch (Exception ae) {}
return "Success";
}
}
web.xml
> <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE web-app PUBLIC
> "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
> "http://java.sun.com/dtd/web-app_2_3.dtd">
>
> <web-app> <servlet>
> <servlet-name>GreetingServiceImpl</servlet-name>
> <servlet-class>com.login.vinayak.server.GreetingServiceImpl</servlet-class>
> </servlet> <servlet-mapping>
> <servlet-name>GreetingServiceImpl</servlet-name>
> <url-pattern>/Login</url-pattern> </servlet-mapping> <!-- Default page to serve --> <welcome-file-list>
> <welcome-file>VinLog.html</welcome-file> </welcome-file-list>
>
> </web-app>
错误列表
com.google.gwt.event.shared.UmbrellaException: One or more exceptions caught, see full set in UmbrellaException#getCauses at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:129) at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:129) at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116) at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:177) at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351) at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307) at sun.reflect.GeneratedMethodAccessor33.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172) at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337) at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218) at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136) at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269) at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91) at com.google.gwt.core.client.impl.Impl.apply(Impl.java) at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213) at sun.reflect.GeneratedMethodAccessor31.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
********* *其他错误原因列表********* *
<小时/>Caused by: com.google.gwt.user.client.rpc.ServiceDefTarget$NoServiceEntryPointSpecifiedException: Service implementation URL not specified at com.google.gwt.user.client.rpc.impl.RemoteServiceProxy.doPrepareRequestBuilderImpl(RemoteServiceProxy.java:430) at com.google.gwt.user.client.rpc.impl.RemoteServiceProxy.doInvoke(RemoteServiceProxy.java:368) at com.google.gwt.user.client.rpc.impl.RemoteServiceProxy$ServiceHelper.finish(RemoteServiceProxy.java:74) at com.login.vinayak.client.GreetingService_Proxy.loginuser(GreetingService_Proxy.java:34) at com.login.vinayak.client.VinLog$2.onClick(VinLog.java:82) at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:54) at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:1) at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1) at com.google.web.bindery.event.shared.EventBus.dispatchEvent(EventBus.java:40) at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193) at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88) at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
请帮我解决问题...TY
最佳答案
...就这样:未指定服务实现 URL...
您需要以某种方式告诉 GWT RPC 调用应该在后端的哪个位置。您可以使用服务接口(interface)上的注释 @RemoteServiceRelativePath 或以编程方式在 ServiceDefTarget 实例(实际上是您的异步服务实例)上执行此操作。
干杯，
关于java - 无法找到错误的根本原因(GWT-Umbrella 异常)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12816777/