Java OOP在公共方法定义上定义特定的方法定义

Question

假设我有一个CommonClass类，它显示所有其他类文件的公共内容：

public class CommonClass {
   public static void displayFoo() {
      ... // printlns here
      displaySpecific(); // Among all files made common by this method, I
                         // want to display something different among the other files
      ... // printlns here
   }
}

我打算这样称呼：

// Filename: fileA.java

public class FileA {
    public static void myFunc() {
         CommonClass.displayFoo();
         // however, I should have a specific definition
         // for the displaySpecific()
         // method. Should I use interfaces? How should it be structured.
    }
    // displaySpecific method here
}

另一个文件：

// Filename: fileB.java

public class FileB {
    public static void myFunc() {
         CommonClass.displayFoo();
         // however, I should have a specific definition
         // for the displaySpecific()
         // method. Should I use interfaces? How should it be structured.
    }
    // displaySpecific method here
}

等等

主要可能是这个

public class MyMain {
   public static void main(String[] args) {
      FilaA.myfunc();
      System.out.println("");
      FileB.myfunc();
      System.out.println("");
      ... and so on...
   }
}

这是预期输出：

Common String Common String Common Common Common Common Common 
Common Common Common Common Common Common Common 
This is File A
Common String Common String Common Common Common Common Common 
Common Common Common Common Common Common Common 

Common String Common String Common Common Common Common Common 
Common Common Common Common Common Common Common 
This is File B
Common String Common String Common Common Common Common Common 
Common Common Common Common Common Common Common 

我该怎么做

Answer 1

如果每个类需要不同的displayFoo()定义，那么它们应该是类函数。你对界面的想法可能就是你想要的方式

public class FileB implements Displayable {
    public static display() {
        // Implementation-specific display
// etc.

然后，只需在可显示的对象上调用display()：

for (Displayable d : displayables) {
    d.display();
}

然而，在您的示例中，您实际上并不需要接口或其他任何东西，因为您正在调用myfunc()，而这反过来又会调用类自己的display()

你可以创建这样的东西：

public class DisplayUtil {
    public static void display(FileA f) {
        // etc.
    }

    public static void display(FileB f) {
        // etc.
    }
}

不太喜欢这种模式，但如果你没有访问原始源代码的权限，或者它们是最终类（我在看你，java.lang.String），它可能是更方便的选择