在Java中使用相同的对象实例

我今天早些时候提出了一个类似的问题，并选择了一个答案，但我认为我没有正确地写出它来得到我需要的答案。请考虑下面的代码..在Java中使用相同的对象实例

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(); 
    } 
}

对象“OBJ”在我的计划是，必须在整个过程中不使用“再创造”它（相同的散列，没有变化）的OAuthService实例。

我用methodA调用“obj”，调用main函数，然后再在methodB中调用“obj”。当我从methodA和methodB打印hashCode时，我得到了不同的结果，告诉我它正在“重新创建”实例。

我该如何避免这种情况？

我敢肯定，这听起来像是一个愚蠢的问题，更有经验的程序员，但我只是开始编程，我找不到我需要的任何解决方案。任何帮助将不胜感激。

实际代码

类 “AuthController”，其中 “OBJ” 是OAuth10aService “服务”，是了methodA “handlePinButton”，并且是的methodB “handlePinSubmit”。我已经尝试与其他两个OAuth库进行身份验证，并得到类似的错误。划线Java是我使用的是什么，现在，

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); 


    } 
}

输出如下：

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

来源

2016-02-12 Shane

可以显示为'someFunction'和'someOtherFunction'相关的代码？很难根据你的描述找出问题的根源 –

是的，我刚刚添加了它。我尝试了两个不同的OAuth库，得到类似的错误，所以我猜测问题不在Scribe-java中，而是在会话实例中。 – Shane

使用Singleton模式。如下所示定义您的班级，并在想要获取唯一的一个对象时，请拨打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; 
    } 
}

来源

2016-02-13 06:15:48

非常感谢。我之前读过关于Singleton的内容，但没有简单地解释它。 – Shane

在Java中使用相同的对象实例

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