公共静态变量和私有静态变量的区别 [英] Difference between public static and private static variables

问题描述

class Employee{
 // salary  variable is a private static variable
private static double salary;

// DEPARTMENT is a constant
 public static final String DEPARTMENT = "Development";

public static void main(String args[]){
   salary = 1000;
  System.out.println(DEPARTMENT+  "  average salary:"+salary);
}
}

这个java程序包含一个静态变量.但我无法理解公共静态变量和私有静态变量之间的区别.

This java program contains a static variable. But I cannot understand the difference between public and private static variables.

推荐答案

公共变量可以在代码中任何地方访问 - 私有变量只能在类本身内访问.在这种情况下，您在 Employee 类中使用了 Employee.salary，所以没问题.

A public variable is accessible everywhere in the code - a private variable is only accessible within the class itself. In this case you're using Employee.salary within the Employee class, so that's fine.

请注意，静态变量是完全独立的事情 - 方法和类具有与变量相同的可访问性.

Note that the variable being static is a completely separate matter - and methods and classes have accessibility in the same way as variables.

还有其他可用的访问级别 - protected 和默认的包"访问(无法明确指定).请参阅 Java 语言规范的 第 6.6 节了解更多详情.

There are other levels of access available too - protected and the default "package" access (which can't be specified explicitly). See section 6.6 of the Java Language Specification for more details.

(作为一个附带问题，还值得了解 static 的含义 - 您几乎肯定不希望这些变量是静态变量，因为它们适用于 each Employee 而不是一般的 Employee 概念.DEPARTMENT 在这里也是一个常量，这很奇怪.)

(As a side matter, it's also worth learning about what static means - you almost certainly don't want these variables to be statics, as they apply to each Employee rather than the Employee concept in general. It's odd for DEPARTMENT to be a constant here, too.)

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