I have a generics class, Foo<T> . In a method of Foo , I want to get the class instance of type T, but I just can't call T.class . What is the preferred way to get around it using T.class ? The short answer is, that there is no way to find out the runtime type of generic type parameters in Java. I suggest reading the chapter about type erasure in the Java Tutorial for more details
我有一个泛型类Foo<T> 。 在Foo一个方法中，我想获得类型T的类实例，但我不能调用T.class 。 什么是使用T.class解决它的首选方法？ 简单的答案是，没有办法找到Java中泛型类型参数的运行时类型。 我建议阅读Java教程中关于类型擦除的章节以获取更多细节。 一个流行的解决方案是将类型参数的Class传递给泛型的构造函数，例如 class Foo<T> { final Class<T> typeParameterClass; public Foo(C
I am trying to post a picture and text to some user's news feed using the Facebook Android SDK (not using the Dialog), but for some reason it posts the picture and text only to the user's own timeline and not to the global news feed where his friends can see it. If I remove the picture param the text is shown in the news feed. Am I missing something? This is my code: //Prepare pictur
我正尝试使用Facebook Android SDK（不使用对话框）将图片和文本发布到某个用户的新闻提要中，但由于某种原因，它仅将图片和文本发布到用户自己的时间轴上，而不是发布到全球新闻提要上他的朋友可以看到它。 如果我删除图片参数，则文本会显示在新闻Feed中。 我错过了什么吗？ 这是我的代码： //Prepare picture data ByteArrayOutputStream baos = new ByteArrayOutputStream(); b.compress(Bitmap.CompressFormat.JPEG,
Following are related to GAE/J local development setup: How do i add/edit entities in local datastore (preferably using some UI)? _ah/admin allows only to view entities. In the local JUnit test cases, how to access the same datastore data that my local web application writes to? I wrote my Test Cases in accordance with http://code.google.com/appengine/docs/java/tools/localunittesting.html b
以下涉及GAE / J本地开发设置： 如何在本地数据存储中添加/编辑实体（最好使用一些用户界面）？ _ah/admin只允许查看实体。 在本地JUnit测试用例中，如何访问与本地Web应用程序写入相同的数据存储区数据？ 我按照http://code.google.com/appengine/docs/java/tools/localunittesting.html编写了测试用例，但测试用例不访问Web应用程序使用的相同数据。 如何在clean-build之间保存本地数据存储数据（现在，local_db.bin被
Is there anyway to get Eclipse to automatically look for static imports? For example, now that I've finally upgraded to Junit 4, I'd like to be able to write: assertEquals(expectedValue, actualValue); hit Ctrl + Shift + O and have Eclipse add: import static org.junit.Assert.assertEquals; Maybe I'm asking too much. I'm using Eclipse Europa, which also has the Favorite prefer
无论如何让Eclipse自动查找静态导入？ 例如，现在我已经升级到Junit 4，我希望能够写出： assertEquals(expectedValue, actualValue); 按Ctrl + Shift + O并让Eclipse添加： import static org.junit.Assert.assertEquals; 也许我问的太多了。 我正在使用Eclipse Europa，它也有收藏偏好部分： 窗口>首选项> Java>编辑器>内容辅助>收藏夹 在我的，我有以下条目（添加时，使用“新类型”，并省略.* ）：
I need to use a cubic B-spline curve but cannot find code for it anywhere. The only curves available in Java API are QuadCurve2D , Path2D and CubicCurve2D . I think they all are Bezier, but I'm not sure about it. If you know where can I find code for cubic B-spline preferably that extends Java Shape class and supports contains(Point p) for onMouseOver please help. Apache has a class to
我需要使用三次B样条曲线，但无法在任何地方找到代码。 Java API中唯一可用的曲线是QuadCurve2D ， Path2D和CubicCurve2D 。 我认为他们都是贝塞尔，但我不确定。 如果您知道哪里可以找到三维B样条代码，最好是扩展Java Shape类，并且支持onMouseOver contains(Point p) ，请大家帮忙。 Apache有一个类来表示样条曲线： http://jmeter.apache.org/api/org/apache/jmeter/visualizers/Spline3.html 但是，它不会扩展Sha
I am trying to get a context specific security Realm in Tomcat 6.0, but when I start Tomcat I get the following error: 09-Dec-2010 16:12:40 org.apache.catalina.startup.ContextConfig validateSecurityRoles INFO: WARNING: Security role name myrole used in an <auth-constraint> without being defined in a <security-role> I have created the following context.xml file: <Context debug="0
我试图在Tomcat 6.0中获得上下文特定的安全领域，但是当我启动Tomcat时，出现以下错误： 09-Dec-2010 16:12:40 org.apache.catalina.startup.ContextConfig validateSecurityRoles INFO: WARNING: Security role name myrole used in an <auth-constraint> without being defined in a <security-role> 我创建了以下的context.xml文件： <Context debug="0" reloadable="true"> <Resource name="MyUse
This question is an exact duplicate of: Java: StreamCorruptedException occur when Decrypt object with DES 1 answer This doesn't make sense. You don't need both the Cipher streams and the SealedObject , and if you consider the actual order of execution of all of these with respect to the Cipher you will see that it isn't symmetrical as between writing and reading. Lose the Seale
这个问题是完全重复的： Java：使用DES 1答案解密对象时发生StreamCorruptedException 这没有意义。 您不需要Cipher流和SealedObject ，如果考虑到所有这些Cipher相对于Cipher的实际执行顺序，您会发现它在写入和读取之间并不对称。 丢失SealedObject ，或丢失Cipher流。
When I try to download Java from Oracle I instead end up downloading a page telling me that I need agree to the OTN license terms. Sorry! In order to download products from Oracle Technology Network you must agree to the OTN license terms. Be sure that... Your browser has "cookies" and JavaScript enabled. You clicked on "Accept License" for the product you wish to do
当我尝试从Oracle下载Java时，我最终下载了一个页面，告诉我需要同意OTN许可条款。 抱歉! 为了从Oracle Technology Network下载产品，您必须同意OTN许可条款。 确保... 您的浏览器具有“cookies”并启用了JavaScript。 您点击了“接受许可证”以查看您想要下载的产品。 您在接受许可证后30分钟内尝试下载。 我如何下载和安装Java？ 对JDK 9进行更新它看起来像现在可以直接从java.net下载它，而无需发送头文件 wget h
I'm trying to decipher the encfs volume key in Java. I ran encfs with the standard settings (ie, 192 bit aes encryption). Is there any way to do this? This is not really a Java question, more an issue of cryptography. A brief investigation into EncFS suggests that the volume key is encrypted by a key derived from a user password. It's probable that this represents the best attack ve
我试图破译Java中的encfs卷密钥。 我用标准设置运行encfs（即192位aes加密）。 有没有办法做到这一点？ 这不是真正的Java问题，更多的是密码学问题。 对EncFS的简要调查表明，音量密钥是由用户密码派生的密钥加密的。 这很可能代表了最好的攻击媒介：一种对希望是弱密码的强力攻击。 然而，我不会抱太大的希望。 对于它的价值， javax.crypto的Java JCE类将是您在Java中执行对称加密的途径。 以下代码片段显示了如何使
I am new to Java and was trying to use Hybrid cryptography using AES-128 Symmetric encryption and then RSA-1024 Asymmetric encryption on the generated symmetric key. Can someone help why I am getting this exception. I have already followed the other posts, and downloaded the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files version 6 in the appropriate folder. Code
我是Java新手，尝试使用AES-128 Symmetric加密的混合加密技术，然后在生成的对称密钥上使用RSA-1024非对称加密。 有人可以帮助我为什么得到这个例外。 我已经关注了其他文章，并在适当的文件夹中下载了Java加密扩展（JCE）无限强度管辖权策略文件版本6。 Code snippet: import java.io.BufferedReader; import java.io.InputStreamReader; import java.security.Key; import java.security.InvalidKeyException; import java.s