重载构造函数：具有两个构造函数的类，一个不带参数，一个带字符串参数

/*时 代 J a v a - N o w J a v a . c o m 提供*/

public class Main {

  public static void main(String[] args) {

    Dog d1 = new Dog();         // Uses Constructor #1

    Dog d2 = new Dog ("Canis"); // Uses Constructor #2

  }

}

class Dog {

  // Constructor #1

  public Dog() {

    System.out.println("A dog is created.");

  }


  // Constructor #2

  public Dog(String nam