从另一个java类调用静态方法
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Calling static method from another java class
提问by LeDoc
I've recently switched from working in PHP to Java and have a query. Want to emphasise I'm a beginner in Java.
我最近从 PHP 工作切换到 Java 并有一个查询。想强调一下我是 Java 的初学者。
Essentially I am working in File A (with class A) and want to refer to a static method saved in File B (class B). Do I need to make any reference to File B when working with class A? (I'm thinking along the lines of require_once in PHP) My code in Class A is as follows:
本质上，我在文件 A（类 A）中工作，并希望引用保存在文件 B（类 B）中的静态方法。使用 A 类时是否需要引用文件 B？（我正在考虑 PHP 中的 require_once ）我在 A 类中的代码如下：
Public class A{
String[] lists = B.staticMethod();
}
Eclipse is not recognising B as a class. Do I need to create an instance of B in order to access the static method. Feel like I'm really overlooking something and would appreciate any input.
Eclipse 没有将 B 识别为一个类。我是否需要创建 B 的实例才能访问静态方法。感觉我真的忽略了一些东西，并且希望得到任何输入。
采纳答案by cmd
Ensure you have proper access to B.staticMethod. Perhaps declare it as
确保您可以正确访问 B.staticMethod。也许将其声明为
public static String[] staticMethod() {
//code
}
Also, you need to import class B
此外，您需要导入 B 类
import foo.bar.B; // use fully qualified path foo.bar.B
public class A {
String[] lists = B.staticMethod();
}
回答by BlakeP
You don't need to create an instance of the class to call a static method, but you do need to import the class.
您不需要创建类的实例来调用静态方法，但确实需要导入类。
package foo;
//assuming B is in same package
import foo.B;
Public class A{
String[] lists = B.staticMethod();
}
回答by Joni
Java has classloader mechanism that is kind of similar to PHP's autoloader. This means that you don't need anything like a includeor requirefunction: as long as the classes that you use are on the "classpath" they will be found.
Java 有类加载器机制，有点类似于 PHP 的自动加载器。这意味着你不需要像 ainclude或require函数这样的东西：只要你使用的类在“类路径”上，它们就会被找到。
Some people will say that you have to use the importstatement. That's not true; importdoes nothing but give you a way to refer to classes with their short names, so that you don't have to repeat the package name every time.
有些人会说你必须使用import语句。这不是真的; import除了给你一种用它们的短名称来引用类的方法之外什么都不做，这样你就不必每次都重复包名。
For example, code in a program that works with the ArrayListand Dateclasses could be written like this:
例如，与ArrayList和Date类一起工作的程序中的代码可以这样编写：
java.util.ArrayList<java.util.Date> list = new java.util.ArrayList<>();
list.add(new java.util.Date());
Repeating the package name gets tiring after a while so we can use importto tell the compiler we want to refer to these classes by their short name:
重复包名一段时间后会很累，所以我们可以import用来告诉编译器我们想通过它们的短名称来引用这些类：
import java.util.*;
....
ArrayList<Date> list = new ArrayList<>();
list.add(new Date());
