在Java中使用相同的對象實例

我今天早些時候提出了一個類似的問題，並選擇了一個答案，但我認爲我沒有正確地寫出它來得到我需要的答案。請考慮下面的代碼..在Java中使用相同的對象實例

public class ClassA { 

    private Main main; 
    Object obj = new Object; 

    public void setMain(Main main) { 
     this.main = main; 
    } 
    methodA() { //called first 
     obj.someFunction(); 
     main.someFunction(); 
    } 
    methodB() { //called second 
     obj.someOtherFunction(); 
    } 
}

對象「OBJ」在我的計劃是，必須在整個過程中不使用「再創造」它（相同的散列，沒有變化）的OAuthService實例。

我用methodA調用「obj」，調用main函數，然後再在methodB中調用「obj」。當我從methodA和methodB打印hashCode時，我得到了不同的結果，告訴我它正在「重新創建」實例。

我該如何避免這種情況？

我敢肯定，這聽起來像是一個愚蠢的問題，更有經驗的程序員，但我只是開始編程，我找不到我需要的任何解決方案。任何幫助將不勝感激。

實際代碼

類「AuthController」，其中「OBJ」是OAuth10aService 「服務」，是了methodA 「handlePinButton」，並且是的methodB 「handlePinSubmit」。我已經嘗試與其他兩個OAuth庫進行身份驗證，並得到類似的錯誤。劃線Java是我使用的是什麼，現在，

public class AuthController { 

private final String CONSUMER_KEY = "asdbfsdfbsdf"; 
private final String CONSUMER_SECRET = "asdfsdbvbvfsdsd"; 


final OAuth10aService service = new ServiceBuilder() 
     .apiKey(CONSUMER_KEY) 
     .apiSecret(CONSUMER_SECRET) 
     .build(TwitterApi.instance()); 
final Token requestToken = service.getRequestToken(); 

Desktop desktop = Desktop.getDesktop(); 

@FXML 
public JFXTextField enterPinField; 
@FXML 
public JFXButton submitPinButton; 

private Main main; 

public void setMain(Main main) { 
    this.main = main; 
} 

public void handlePinButton() throws Exception { //call first 

    System.out.println(service.hashCode()); 
    String authUrl = service.getAuthorizationUrl(requestToken); 
    desktop.browse(new URI(authUrl)); 
    main.secondWindow(); 

} 

public void handlePinSubmit() throws Exception { //call second 

    System.out.println(service.hashCode()); 

    Verifier verifier = new Verifier(enterPinField.getText()); 
    System.out.println(verifier); 

    Token accessToken = service.getAccessToken(requestToken, verifier); 
    System.out.println(accessToken); 


    } 
}

輸出如下：

WARNING: Loading FXML document with JavaFX API of version 8.0.65 by JavaFX runtime of version 8.0.51 
722985119 
Feb 12, 2016 4:47:05 PM javafx.fxml.FXMLLoader$ValueElement processValue 
WARNING: Loading FXML document with JavaFX API of version 8.0.65 by JavaFX runtime of version 8.0.51 
960671619 
[email protected] 
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException 
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1770) 
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1653) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Node.fireEvent(Node.java:8390) 
    at javafx.scene.control.Button.fire(Button.java:185) 
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89) 
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3758) 
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3486) 
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762) 
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2495) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:350) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$350(GlassViewEventHandler.java:385) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda$166/1959217067.get(Unknown Source) 
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:404) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:384) 
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555) 
    at com.sun.glass.ui.View.notifyMouse(View.java:927) 
Caused by: java.lang.reflect.InvocationTargetException 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:497) 
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1767) 
    ... 46 more 
Caused by: com.github.scribejava.core.exceptions.OAuthException: Response body is incorrect. Can't extract token and secret from this: 'Error processing your OAuth request: Invalid oauth_verifier parameter' 
    at com.github.scribejava.core.extractors.TokenExtractorImpl.extract(TokenExtractorImpl.java:39) 
    at com.github.scribejava.core.extractors.TokenExtractorImpl.extract(TokenExtractorImpl.java:29) 
    at com.github.scribejava.core.oauth.OAuth10aService.getAccessToken(OAuth10aService.java:86) 
    at controller.AuthController.handlePinSubmit(AuthController.java:65) 
    ... 56 more

來源

2016-02-12 Shane

可以顯示爲'someFunction'和'someOtherFunction'相關的代碼？很難根據你的描述找出問題的根源 –

是的，我剛剛添加了它。我嘗試了兩個不同的OAuth庫，得到類似的錯誤，所以我猜測問題不在Scribe-java中，而是在會話實例中。 – Shane

使用Singleton模式。如下所示定義您的班級，並在想要獲取唯一的一個對象時，請撥打MyClass.getInstance()而不是new MyClass()。

public class MyClass 
{ 
    /** 
    * Create the only one instance of this class. 
    */ 
    private static final MyClass sInstane = new MyClass(); 

    /** 
    * This is the only one constructor in this class. 
    * Because this is 'private', no others can create 
    * instances of this class. 
    */ 
    private MyClass() 
    { 
    } 

    /** 
    * Get the only one instance of this class. 
    */ 
    public static MyClass getInstance() 
    { 
     return sInstance; 
    } 
}

來源

2016-02-13 06:15:48

非常感謝。我之前讀過關於Singleton的內容，但沒有簡單地解釋它。 – Shane

在Java中使用相同的對象實例

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