자바 제4 절 류 의 계승 / 추상 / 인터페이스 / 다 형 성
11084 단어 자바
/*
java ，
， ， B A, C B
C A
， ，
super( )
， this ，
1 ， new
3.1
2 ， new Person( )
3 this() ， ( 2 )
， ， 6
4 ( Ojbect ，Object java )
， 2 ， ， ，
5 ，
6
1): super() this() ？
this() ， super()
， super() ， ，
2): super() this()
,
， this super()
this, this super()
，
， super
，
final
1 java ， ， final
2 final
3 final
4 final ( ) ，
5 final
final ，
final ，
6 public static final ，
java ，
，
1 abstract ， abstract
2 ， new
3 ，
4 ， ，
*/
//final class Person
class Person
{
//protected final String name = "unknown"; final
protected String name = "unknown";
//public final String x = "abc"; //
public final String x;
//public static final String x;
public static final String y = "abc";
public int age = -1;
public Person()
{
this.x = "cde";
}
public Person(String name, int age)
{
this.name = name;
this.age = age;
//
this.x = "abc";
}
//public void getInfo(){}
public void getInfo()
{
//this.x = "abc"; // final
System.out.println("name:"+name+", age:"+age);
}
};
class Student extends Person
{
public String school = "unknown";
public Student()
{
//super("xlc",15);
super();
}
public Student(String name, int age, String school)
{
this(name,age); //
this.school = school;
//this(name,age); //
}
public Student(String name, int age)
{
super(name, age);
}
public void getInfo()
{
System.out.println("school:"+school+"name:"+name+", age:"+age);
super.getInfo();
}
public void study()
{
}
};
class TestStudent
{
public static void main(String[] args)
{
//Student st = new Student();
//st.name = "xlc";
//st.age = 34;
//st.getInfo();
Student st = new Student("xlc",22," ");
st.getInfo();
System.out.println(Float.MAX_VALUE);
}
};
/*
(interface)
， ，
， ，
，
1 public ， public static final
2 extends
3 implements ， implements
4 ， ，extneds implements
1
2
3 instanceof
4 Object equals
*/
/*abstract class A
{
abstract int aa(int x, int y);
//
};
class B extends A
{
int aa(int x, int y)
{
return 1;
}
};*/
interface Runner
{
int ID = 1;
void run();
}
interface Animal extends Runner
{
void breathe();
}
class Fish implements Animal
{
public void run()
{
System.out.println("fish is swimming");
}
//public void breathe()
public void breathe()
{
System.out.println("fish is bubbling");
}
public static void main(String[] args)
{
Fish f = new Fish();
int j=0;
j = Runner.ID;
j = f.ID;
//f.ID = 2; //
}
};
abstract class LandAnimal implements Animal
{
public void breathe()
{
}
};
interface dog
{
void uaau();
}
interface Flyer
{
void fly();
}
class Bird implements Runner, Flyer
{
public void run()
{
}
public void fly()
{
}
};
// ，
//
class Student extends Person implements Runner, dog
// ，extends implements
{
public void run()
{
}
public void uaau()
{
}
};
interface A
{
//public static final int ID=1;
//int ID = 1; // ， ， ,
//
public static final int ID=1;
int aa(int x, int y);
void bb();
}
/*class
{
public static void main(String[] args)
{
System.out.println("Hello World!");
}
}*/
/*
1): （ ）
， " "，
2): ， ，
， ( callA ) ( A ， D)
*/
class A
{
public void func1()
{
System.out.println("A func1 is calling");
}
public void func2()
{
func1();
}
};
class B extends A
{
public void func1()
{
System.out.println("B func1 is calling");
}
public void func3()
{
System.out.println("B func3 is calling");
}
};
class C
{
public static void main(String[] args)
{
B b = new B();
callA(b);
//A aa = b;
//callA(new A());
}
public static void callA(A a)
{
/*if(a instanceof B)
{
B b = (B)a; //
b.func1();
b.func2();
b.func3();
}else{
a.func1();
a.func2();
}*/
a.func1();
a.func2();
//a.func1();
//a.func2();
//a.func3();
}
};
class Student extends Object
{
private String name;
private int age;
public Student(String name, int age)
{
this.name = name;
this.age = age;
}
/*public boolean equals(Object obj)
{
Student st = null;
if(obj instanceof Student)
{
st = (Student)obj;
if(st.name == name && st.age == age)
{
return true;
} else{
return false;
}
}else{
return false;
}
}*/
// equals ，
//
public static void main(String[] args)
{
Student st1 = new Student(" ",20);
Student st2 = new Student(" ",20);
if(st1.equals(st2))
{
System.out.println(" ");
}else{
System.out.println(" ");
}
}
};
/*class
{
public static void main(String[] args)
{
System.out.println("Hello World!");
}
}*/
interface PCI
{
void start();
void stop();
}
class NetWrokCard implements PCI
{
public void start()
{
System.out.println("Send...");
}
public void stop()
{
System.out.println("stop...");
}
};
class SoundCard implements PCI
{
public void start()
{
System.out.println("du...");
}
public void stop()
{
System.out.println("sound stop...");
}
};
class MainBoard
{
public void usePCICard(PCI p)
{
p.start();
p.stop();
}
};
class Assembler
{
public static void main(String[] args)
{
MainBoard mb = new MainBoard();
NetWrokCard nc = new NetWrokCard();
SoundCard sc = new SoundCard();
mb.usePCICard(nc);
mb.usePCICard(sc);
//
/*mb.usePCICard(
new PCI()
{
public void start()
{
System.out.println("test start...");
}
public void stop()
{
System.out.println("test end...");
}
}
);*/
//
class A implements PCI
{
public void start()
{
System.out.println("test start...");
}
public void stop()
{
System.out.println("test end...");
}
};
mb.usePCICard(new A());
}
};
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