[JAVA][从0开始的JAVA随笔]静态(static)属性的使用方法及注意事项

class Static_test{
    
    Static_test(){
        s_int = 1;
    }
    
    public static int s_int;
    
    public static void s_func(){
        System.out.println("s_int = "+s_int);
    }
}

public class Hello{
    
    Hello(){

    }
    
    public void seta(int num){
        a = num;
    }
    
    public void setb(int num){
        b = num;
    }
    public void showa(){
        System.out.println("a = "+a);
    }
    public void showb(){
        System.out.println("b = "+b);
    }
    
    public static int a;
    public int b;
    
    static class Static_class{
        
        Static_class(){
            s_int = 2;
        }
        
        public static int s_int;
        
        public static void s_func(){
            System.out.println("s_int = "+s_int);
        }
    }

    public static void main(String[] args){
        Hello h1 = new Hello();
        Hello h2 = new Hello();
        System.out.println("h1:");
        h1.showa();
        h1.seta(4);
        h1.setb(2);
        h1.showb();
        System.out.println("h2:");
        h2.showa();
        h2.setb(3);
        h2.showb();
        System.out.println("h:");
        System.out.println("a = "+Hello.a);
        
        Static_test st = new Static_test();
        
        Static_class sc = new Static_class();
        
        Static_test.s_func();
        
        Static_class.s_func();
    }
}