Java基础类Class使用指南

public class Test {
  
  public static void main(String[] args) {
    //通过new实例化一个对象
    Foo foo = new Foo();
    //通过实例化对象的getClass()方法得到Class类的实例
    Class c1 = foo.getClass();
    //任何一个类都有一个隐含的静态变量class
    Class c2 = Foo.class;
    //c1、c2表示了Foo类的类类型(class type)
    System.out.println(c1 == c2);
    
    Class c3 = null;
    try {
      //第三种获得类的类类型的方法
      c3 = Class.forName("com.edu.hpu.Foo");
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
    System.out.println(c1 == c3);
    
    try {
      //通过类的类类型来创建类的实例对象
      Foo c4 = (Foo) c1.newInstance();
      c4.start();
    } catch (InstantiationException e) {
      e.printStackTrace();
    } catch (IllegalAccessException e) {
      e.printStackTrace();
    }
  }

}

class Foo{
  public void start(){
    System.out.println("Foo类");
  }
}

class Offices{
  public static void main(String [] args){
    if("Word".equals(args[0])){
      Word w = new Word();
      w.start();
    }
    if("Excel".equals(args[0])){
      Excel e = new Excel();
      e.start();
    }
  }
}

class Office{
  public static void main(String [] args){
    try{
      Class c = Class.forName(args[0]);
      OfficeAble oa = (OfficeAble)c.newInstance();
      oa.Write();
    }catch(Exception e){e.printStackTrace();}
  }
}

interface OfficeAble{
  public void Write();
}
class Word implements OfficeAble{
  public void Write(){
    System.out.println("Word...start...");
  }
}
class Excel implements OfficeAble{
  public void Write(){
    System.out.println("Excel..Write..");
  }
}