如何在Java中从另一个类（非继承）调用一个类？

Question

我不记得当在Java中另一个类的方法（例如在主类中）调用扫描程序类以在用户输入中进行扫描时调用的名称吗？

Answer 1

I think you're looking for the names of associations like aggregation and composition. The terms are used to describe Releationships in UML

Answer 2

If the scan method is an instance (object) method (not static), it would be something like this

Scanner s = new Scanner();
s.scan();

If scan is static (a class method), then

Scanner.scan();

Edit: The name of the relationship is Dependency in UML. You say that Main depends on Scanner or Main uses-a Scanner. I made this UML slideshow and cheatsheet:

http://www.loufranco.com/blog/files/UMLCheatsheet.html

If you have a Scanner member in the main class, then this is usually called has-a, composition, or an association.

Answer 3

Your question is not clear.

but maybe the following example will help:

class Scanner{
  public void scan(){}
}

//use inheritance
class SubScanner extends Scanner{
  public void scan(){}       //overriding
  public void scan(int i){}  //overloading
}

//use aggreagation
class MainClass{
  private final Scanner scanner;
  MainClass(Scanner scanner){
    this.scanner = scanner;
  }
  public void scan(){ 
    scanner.scan();         //delegation call
  }
}

Answer 4

Here is a table of many UML relationships

http://publib.boulder.ibm.com/infocenter/rtnlhelp/v6r0m0/index.jsp?topic=/com.ibm.xtools.modeler.doc/topics/rreltyp.html