Take this for example (excerpt from Java regex checker not working): while(!checker) { matcher = pattern.matcher(number); if(matcher.find()) checker = true; else year++; } Would it matter if .equals(false) was used to check for the value of the Boolean checker ? I know that there is this which is rather similar. However, obviously the question deals with primitive
以此为例（摘自Java正则表达式检查器不起作用）： while(!checker) { matcher = pattern.matcher(number); if(matcher.find()) checker = true; else year++; } 如果使用.equals(false)来检查Boolean checker的值，它会影响吗？ 我知道这有些相似。 然而，显然这个问题涉及原始boolean而不是对象包装器， Boolean ; 因此.equals()将不适用。 另外， Boolean应该处理不同于boolean ？ 从您
I would like to know if it was possible to detect the double-click in JavaFX 2 ? and how ? I would like to make different event between a click and a double click. Thanks Yes you can detect single, double even multiple clicks: myNode.setOnMouseClicked(new EventHandler<MouseEvent>() { @Override public void handle(MouseEvent mouseEvent) { if(mouseEvent.getButton().equa
我想知道是否有可能检测到JavaFX 2中的双击？ 如何 ？ 我想在点击和双击之间做出不同的事件。 谢谢 是的，您可以检测单个，双击甚至多个点击： myNode.setOnMouseClicked(new EventHandler<MouseEvent>() { @Override public void handle(MouseEvent mouseEvent) { if(mouseEvent.getButton().equals(MouseButton.PRIMARY)){ if(mouseEvent.getClickCount() == 2){ Sy
This question already has an answer here: Comparing Java enum members: == or equals()? 15 answers Both are correct, .equals() defers to ==. == would avoid NullPointerException
这个问题在这里已经有了答案： 比较Java枚举成员：==或equals（）？ 15个答案 两者都是正确的，.equals（）推迟到==。 ==会避免NullPointerException
This question already has an answer here: Understanding Enums in Java 6 answers Life span of a Java enum instance 2 answers Comparing Java enum members: == or equals()? 15 answers Enums in java are classes with several constant instances of themselves. These are created like static final variables. Accessing an enum constant returns a reference to the enum constant. It does not create
这个问题在这里已经有了答案： 了解Java 6中的枚举答案 Java枚举实例2的生命周期应答 比较Java枚举成员：==或equals（）？ 15个答案 java中的枚举类是包含多个常量实例的类。 这些被创建为static final变量。 访问枚举常量返回对枚举常量的引用。 它不创建枚举常量的新实例。
This question already has an answer here: Comparing Java enum members: == or equals()? 15 answers == should work fine with enums because there aren't multiple references of a given enum item; there's just one. The Java Language Specification section on enum types, 8.9 states that they are implicitly static and final and so can only be created once. You are comparing enum constant
这个问题在这里已经有了答案： 比较Java枚举成员：==或equals（）？ 15个答案 ==应该对枚举工作正常，因为没有给定枚举项的多个引用; 只有一个。 关于枚举类型的Java语言规范部分，8.9声明它们是隐式静态和最终的，因此只能创建一次。 您正在比较枚举常量 。 这意味着对于每个枚举常量，都会创建一个实例。 这个 enum Drill{ ATTENTION("Attention!"), AT_EASE("At Ease"); ... } 或多或少相当于 final c
This question already has an answer here: Comparing Java enum members: == or equals()? 15 answers Use == . There cannot be multiple instances of the same enum constant (within the context of a classloader, but let's ignore that point) so it's always safe. That said, using equals() is safe too, and will perform reference equality as well. It's pretty much a style choice. Per
这个问题在这里已经有了答案： 比较Java枚举成员：==或equals（）？ 15个答案 使用== 。 不能有多个相同枚举的实例（在类加载器的上下文中，但让我们忽略该点），所以它总是安全的。 也就是说，使用equals()也是安全的，并且也会执行引用平等。 这几乎是一种风格选择。 就我个人而言，我很少发现自己使用if语句来完成枚举。 我喜欢switch块。 switch (c1) { case Brown: //is brown break;
The wikipedia article on Singletons mentions a few thread safe ways to implement the structure in Java. For my questions, let's consider Singletons that have lengthy initialization procedures and are acccessed by many threads at once. Firstly, is this unmentioned method thread-safe, and if so, what does it synchronize on? public class Singleton { private Singleton instance; priva
关于Singletons的维基百科文章提到了几种线程安全的方式来实现Java中的结构。 对于我的问题，让我们考虑具有冗长的初始化过程并且一次被许多线程共享的单例。 首先，这是未提及的方法是否是线程安全的，如果是这样，它在什么时候同步呢？ public class Singleton { private Singleton instance; private Singleton() { //lots of initialization code } public static synchronized Singleton getI
I am using Renjin to use R code in Java. when I am running R code with syntax: "engine.eval(new java.io.FileReader("Forecast_temp.R"));" where "Forecast_temp.R" is the R code file. Renjin is showing some messages as given below Loading required package: stats Loading required package: graphics Loading required package: zoo Loading required package: stats
我使用Renjin在Java中使用R代码。 当我使用语法运行R代码时：“engine.eval（new java.io.FileReader（”Forecast_temp.R“））;” 其中“Forecast_temp.R”是R代码文件。 人人正在显示如下所示的一些消息 加载所需的软件包：统计 加载需要的软件包：图形 加载所需的软件包：动物园 加载所需的软件包：统计 加载需要的包：timeDate 加载需要的软件包：图形 加载所需的软件包：utils 加载所需的软件包：统计 加载
Since I use streams a great deal, some of them dealing with a large amount of data, I thought it would be a good idea to pre-allocate my collection-based collectors with an approximate size to prevent expensive reallocation as the collection grows. So I came up with this, and similar ones for other collection types: public static <T> Collector<T, ?, Set<T>> toSetSized(int init
由于我使用流很多，其中一些处理大量的数据，我认为这是一个好主意，预先分配我的基于收集器的收集器大致的大小，以防止收集增长时的昂贵的重新分配。 所以我想出了这个，其他类型的集合类似： public static <T> Collector<T, ?, Set<T>> toSetSized(int initialCapacity) { return Collectors.toCollection(()-> new HashSet<>(initialCapacity)); } 像这样使用 Set<Foo> fooSet = my
I'm building a java application with tomcat embedded and jersey REST. What i need to do is to implement a VERY simple (and single) file upload inside this application but i can't find anywhere a guide for my context...i just found a file upload solution but NOT with embedded tomcat. Any suggestions? Thanks everyone in advice and sorry for my English If you are using Spring Boot fo
我正在用tomcat嵌入式和JEST REST构建一个Java应用程序。 我需要做的是在这个应用程序内部实现一个非常简单的（和单一的）文件上传，但是我找不到任何指向我的上下文的地方......我刚刚找到了一个文件上传解决方案，但没有嵌入tomcat。 有什么建议么？ 感谢大家的建议并为我的英语感到难过 如果你使用嵌入式Tomcat的Spring Boot，那么下面的代码示例会帮助你。 @Controller public class FileUploadController { @R