标签:c style class blog code java
子类在继承父类后,创建子类对象会首先调用父类的构造函数,先运行父类的构造函数,然后再运行子类的构造函数,例如以下所看到的:
class Father{
public Father(){
System.out.println("I am father");
}
}
public class Child extends Father{
public Child(){
System.out.println("I am child");
}
public static void main(String[] args) {
Father f=new Father();
Child c=new Child();
}
}当父类有带參数的构造函数时,子类默认是调用不带參数的构造函数,例如以下所看到的:
class Father{
public Father(){
System.out.println("I am father");
}
public Father(String name){
System.out.println("I am father,My name is "+name);
}
}
public class Child extends Father{
public Child(){
System.out.println("I am child");
}
public static void main(String[] args) {
Father f=new Father("Apache");
Child c=new Child();
}
}若想子类调用父类带參数的构造函数,须要用super()函数申明,例如以下:
class Father{
public Father(){
System.out.println("I am father");
}
public Father(String name){
System.out.println("I am father,My name is "+name);
}
}
public class Child extends Father{
public Child(){
super("Apache");
System.out.println("I am child");
}
public static void main(String[] args) {
Father f=new Father("Apache");
Child c=new Child();
}
}java继承时候类的运行顺序问题,布布扣,bubuko.com
标签:c style class blog code java
原文地址:http://www.cnblogs.com/hrhguanli/p/3777254.html