1.类变量 即static
public class Demo{
public static void main(String[] args){
Child ch1 = new Child(3,"妞妞");
ch1.joinGame();
Child ch2 = new Child(4,"小小");
ch2.joinGame();
Child ch3 = new Child(5,"大大");
ch3.joinGame();
System.out.println("共有="+Child.total);
}
}
class Child{
int age;
String name;
static int total=0;
public Child(int age,String name){
this.age=age;
this.name=name;
}
public void joinGame(){
total++;
}
}
2.类方法
public class Demo{
public static void main(String[] args){
Stu stu1 = new Stu(29,"aa",340);
Stu stu2 = new Stu(29,"bb",240);
System.out.println(Stu.getTotalFee());
}
}
class Stu{
int age;
String name;
int fee;
static int totalFee;
public Stu(int age,String name,int fee){
this.age = age;
this.name = name;
totalFee+=fee;
}
public static int getTotalFee(){//这是一个静态方法
return totalFee;
age ++；//错的，
}
}
***static静态方法可以访问static静态变量，不能访问非静态变量，非静态方法可以访问静态和非静态变量。