GWT RequestFactory 与 Objectify：触发请求时返回 ServerFailure 错误

Question

我正在尝试在 Eclipse 上自定义 App Engine Connected Android 项目。我使用 Objectify 代替 JPA，并一直遵循 Turbocharge 示例设置我的基本框架（使用 DAO 层）。

我目前正在处理 Web 方面的工作，但我无法让我的实体保留在开发服务器上：我的请求在接收器的 onFailure() 方法上返回 ServerFailure 错误。但并没有真正提供任何关于原因的线索（所有变量均为空）。

任何帮助将不胜感激！

这是我的 EntryPoint 类：

public class Manager implements EntryPoint {
private static final Logger log = Logger.getLogger(Manager.class.getName());
private final EventBus eventBus = new SimpleEventBus();
private ManagerRequestFactory rf = GWT.create(ManagerRequestFactory.class);

@Override
public void onModuleLoad() {
    GWT.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {

        @Override
        public void onUncaughtException(Throwable e) {
            log.finest("uncaught exception: ");
            e.printStackTrace();
        }
    });

    rf.initialize(eventBus);
    log.setLevel(Level.FINE);   
    PersonRequest personRequest = rf.personRequest();

    // Populate the database with sample data
    PersonProxy person = personRequest.create(PersonProxy.class);

    person.setFirstName("John1");
    person.setLastName("Doe");
    person.setEmail("[email protected]");
    person.setMainPhone("215-555-1212");
    personRequest.saveAndReturn(person).fire(new Receiver<PersonProxy>(){

        @Override
        public void onSuccess(PersonProxy response) {
            log.info("got response: " + response.getFirstName());

        }

        @Override
        public void onFailure(ServerFailure error) {
            log.info("Server Failure type: " + error.getExceptionType());
            log.info("Failure message: " + error.getMessage());
            log.info("Stack Trace: " + error.getStackTraceString());
            log.info(error.isFatal() ? "error is fatal" : "error is not fatal");
            super.onFailure(error);
        }
    });

我在调试模式下跟踪代码通过堆栈直到它返回错误的位置。这是堆栈

守护线程 [来自 Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.7 (KHTML，如 Gecko) Chrome/16.0.912.75 Safari/535.7 的管理器代码服务器 http://127.0.0.1:8888/manager/hosted.html?manager @ d6:JVCMo.q:W,$wW]（已暂停（异常 UmbrellaException））

AbstractRequestContext$StandardPayloadDialect.processPayload(Receiver<Void>, String) line: 387  
AbstractRequestContext$5.onTransportSuccess(String) line: 1108  
DefaultRequestTransport$1.onResponseReceived(Request, Response) line: 136   
Request.fireOnResponseReceived(RequestCallback) line: 287   
RequestBuilder$1.onReadyStateChange(XMLHttpRequest) line: 395   
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
NativeMethodAccessorImpl.invoke(Object, Object[]) line: not available   
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: not available   
Method.invoke(Object, Object...) line: not available    
MethodAdaptor.invoke(Object, Object...) line: 103   
MethodDispatch.invoke(JsValue, JsValue[], JsValue) line: 71 
OophmSessionHandler.invoke(BrowserChannelServer, BrowserChannel$Value, int, BrowserChannel$Value[]) line: 172   
BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer$SessionHandlerServer) line: 337  
BrowserChannelServer.invokeJavascript(CompilingClassLoader, JsValueOOPHM, String, JsValueOOPHM[], JsValueOOPHM) line: 218   
ModuleSpaceOOPHM.doInvoke(String, Object, Class<?>[], Object[]) line: 136   
ModuleSpaceOOPHM(ModuleSpace).invokeNative(String, Object, Class<?>[], Object[]) line: 561  
ModuleSpaceOOPHM(ModuleSpace).invokeNativeObject(String, Object, Class<?>[], Object[]) line: 269    
JavaScriptHost.invokeNativeObject(String, Object, Class<?>[], Object[]) line: 91    
Impl.apply(Object, Object, Object) line: not available  
Impl.entry0(Object, Object, Object) line: 213   
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
NativeMethodAccessorImpl.invoke(Object, Object[]) line: not available   
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: not available   
Method.invoke(Object, Object...) line: not available    
MethodAdaptor.invoke(Object, Object...) line: 103   
MethodDispatch.invoke(JsValue, JsValue[], JsValue) line: 71 
OophmSessionHandler.invoke(BrowserChannelServer, BrowserChannel$Value, int, BrowserChannel$Value[]) line: 172   
BrowserChannelServer.reactToMessages(BrowserChannelServer$SessionHandlerServer) line: 292   
BrowserChannelServer.processConnection() line: 546  
BrowserChannelServer.run() line: 363    
Thread.run() line: not available    

在这里我有响应和错误变量的快照：

response    ResponseMessageAutoBean$1  (id=566) 
    this$0  ResponseMessageAutoBean  (id=581)   
        data    JsonSplittable  (id=583)    
            array   null    
            bool    null    
            isNull  false   
            number  null    
            obj JSONObject  (id=597)    
            reified HashMap<K,V>  (id=598)  
            string  null    
        factory MessageFactoryImpl  (id=584)    
            creatorMap  JavaScriptObject$  (id=608) 
            enumToStringMap HashMap<K,V>  (id=609)  
            stringsToEnumsMap   HashMap<K,V>  (id=610)  
        frozen  false   
        shim    ResponseMessageAutoBean$1  (id=566) 
            this$0  ResponseMessageAutoBean  (id=581)   
                data    JsonSplittable  (id=583)    
                factory MessageFactoryImpl  (id=584)    
                frozen  false   
                shim    ResponseMessageAutoBean$1  (id=566) 
                tags    null    
                usingSimplePeer true    
                wrapped ResponseMessageAutoBean$2  (id=587) 
        tags    null    
        usingSimplePeer true    
        wrapped ResponseMessageAutoBean$2  (id=587) 

causes  HashSet<E>  (id=570)    
    [0] RuntimeException  (id=576)  
        cause   RuntimeException  (id=576)  
        detailMessage   "Server Error: null" (id=579)   
        stackTrace  null    

Answer 1

此错误表明服务器出现错误，因此“服务器错误：null” - 引发了异常，但没有与之关联的消息发送到客户端。根据您的代码，它可能位于服务器上的 saveAndReturn 方法中。尝试单步执行该步骤，或者使用 try/catch 围绕方法主体以获取错误。如果发生错误时使用了足够的日志记录，您的服务器日志可能会更清楚地说明该问题。