expression是需要评估的表达式,value1、value2等是可能的常量值,当expression的值与某个case标签匹配时,执行相应的代码块。break语句用于跳出switch语句,防止执行后续的case代码块(即所谓的“贯穿”现象)。default标签是可选的,当没有case匹配时执行default代码块。 2. switch语句中case标签的要求 在Java中,switch语句的...
It throws a “Constant expression required” error when it’s compiled and it points to the case p: line, however, it also throws it for f: if I switch them so I must be doing something completely off. 解决方案 Yes, a case expression has to be a constant (or an enum constant name...
然后,我想要一种基于常量获得相关字符串的方法: public static String lookup(int constant) { switch (constant) { case Foo.BAR: return "bar"; case Foo.BAZ: return "baz"; case Foo.BAM: return "bam"; default: return "unknown"; }} 但是,当我编译时,我会得到一个constant expression required三个...
public static String lookup(int constant) { switch (constant) { case Foo.BAR: return "bar"; case Foo.BAZ: return "baz"; case Foo.BAM: return "bam"; default: return "unknown"; } } 但是,当我编译时,我在 3 个案例标签中的每一个上都收到 constant expression required 错误。 我知道编译...
You can't apply logical complement ! to a numeric expression, nor can you apply a negation operator - to a boolean expression. int x = -5; booean y = !true; 2) Increment ++ and Decrement Operators -- pre-increment and pre-decrement operators:new value returned; ...
Over time, optional packages may become required in an edition as the marketplace requires them. ORB Object Request Broker. A library than enables CORBA objects to locate and communicate with one another. OS principal A principal native to the operating system on which the Java platform is execu...
安全问题其实是很多程序员想了解又容易忽略的问题,但需要我们重视起来,提高应用程序的安全性。常出现的安全问题包括,程序接受数据可能来源于未经验证的用...
The minimum version of Java required for Java Plugin and Java Webstart is now Java 5. Applets that do not run in Java 5 or later must be ported to a later version of Java to continue to function. Applets written for earlier versions but able to run in at least Java 5 will continue ...
Create objects early, when there is spare time in the application, and hold those objects until required. Use lazy initialization when there are objects or variables that may never be used, or when you need to distribute the load of creating objects. Use lazy initialization only when there is...
If a line terminator is not required at the end of the string, then the closing delimiter can be placed on the last line of content. For example, the text block: """ line 1 line 2 line 3""" is equivalent to the string literal: ...