在方法之间 Java 中使用相同的对象实例
Using same object instance in Java between methods
我今天早些时候问了一个类似的问题并选择了一个答案，但我认为我的措辞不正确，无法获得我需要的答案。请考虑下面的代码..
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();
}
}
我程序中的对象 "obj" 是一个 OAuthService 实例，必须在没有 "re-creating" 的情况下在整个过程中使用它（相同的散列，没有变化）。
我用 methodA 调用 "obj"，在 main 中调用一个函数，然后在 methodB 中再次调用 "obj"。当我从 methodA 和 methodB 打印 hashCodes 时，我得到不同的结果，告诉我它是 "re-creating" 实例。
我怎样才能避免这种情况？
我敢肯定，对于更有经验的程序员来说，这听起来像是一个愚蠢的问题，但我才刚刚开始编程，而且我在任何地方都找不到我需要的解决方案。任何帮助将不胜感激。
实际代码
Class "AuthController"，其中 "obj" 是 OAuth10aService "service"，方法 A 是 "handlePinButton"，方法 B 是 "handlePinSubmit"。我已尝试使用其他两个 OAuth 库对 java 进行身份验证，但遇到了类似的错误。 Scribe-java是我现在用的，
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$ValueElement processValue
WARNING: Loading FXML document with JavaFX API of version 8.0.65 by JavaFX runtime of version 8.0.51
960671619
com.github.scribejava.core.model.Verifier@2546ed3b
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1770)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1653)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8390)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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.access00(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$MouseEventNotification.run(GlassViewEventHandler.java:275)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent0(GlassViewEventHandler.java:385)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda6/1959217067.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
使用单例模式。如下定义 class 并在您想要获得唯一一个对象时调用 MyClass.getInstance() 方法而不是 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;
}
}
我今天早些时候问了一个类似的问题并选择了一个答案，但我认为我的措辞不正确，无法获得我需要的答案。请考虑下面的代码..
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();
}
}
我程序中的对象 "obj" 是一个 OAuthService 实例，必须在没有 "re-creating" 的情况下在整个过程中使用它（相同的散列，没有变化）。
我用 methodA 调用 "obj"，在 main 中调用一个函数，然后在 methodB 中再次调用 "obj"。当我从 methodA 和 methodB 打印 hashCodes 时，我得到不同的结果，告诉我它是 "re-creating" 实例。
我怎样才能避免这种情况？
我敢肯定，对于更有经验的程序员来说，这听起来像是一个愚蠢的问题，但我才刚刚开始编程，而且我在任何地方都找不到我需要的解决方案。任何帮助将不胜感激。
实际代码
Class "AuthController"，其中 "obj" 是 OAuth10aService "service"，方法 A 是 "handlePinButton"，方法 B 是 "handlePinSubmit"。我已尝试使用其他两个 OAuth 库对 java 进行身份验证，但遇到了类似的错误。 Scribe-java是我现在用的，
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
com.github.scribejava.core.model.Verifier@2546ed3b
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.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.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.access00(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$handleMouseEvent0(GlassViewEventHandler.java:385)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda6/1959217067.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
使用单例模式。如下定义 class 并在您想要获得唯一一个对象时调用 MyClass.getInstance() 方法而不是 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;
}
}