调用基类的构造函数

Question

public class Animal {
public Animal(String aType) {
type = new String(aType);
}

public String toString() {
return "This is a " + type;
}

private String type;
}

public class Dog extends Animal {
public Dog(String aName) {
super("Dog");
name = aName;
breed = "Unknown";
}
public Dog(String aName, String aBreed) {
super("Dog");
name = aName;
breed = aBreed;
}

private String name;
private String breed;
}

public class TestBerived {
public static void main(String[] args) {
Dog aDog = new Dog("Fido", "Chihuahua");
Dog starDog = new Dog("Lassie");
System.out.println(aDog);
System.out.println(starDog);
}
}

输出结果是：
This is a Dog
This is a Dog

[size=x-small]请问调用基类的构造函数为何会隐含调用基类的toString方法呢？[/size]

Answer 1

[code="java"]
public Dog(String aName) {
super("Dog");
name = aName;
breed = "Unknown";
}
public Dog(String aName, String aBreed) {
super("Dog");
name = aName;
breed = aBreed;
}
[/code]
大哥，你在这里面 就把type赋值为"Dog"，然后System.out.println(aDog)，就会调用toString()方法了