头歌Java实验面向对象高级

第1关：类的继承和super关键字

java">package step1;class Animal{String name;public void shout(){System.out.println(this.name + "发出叫声");}public Animal(String name) {this.name = name;}
}// ---------------------Begin------------------------
//编写Dog类继承Animal类，重写shout方法，增加superShout方法
class Dog extends Animal{public Dog(String name) {super(name);}public void shout(){System.out.println(this.name+"发出汪汪叫");}public void superShout(){super.shout();}
}// ---------------------End------------------------

第2关：final关键字改错

java">package step2;// ---------------------Begin------------------------class Person{int age;String name;public void sayHello(){System.out.println("nice to meet you.");}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}
}
class  Student extends Person{@Overridepublic void sayHello() {System.out.println(String.format("Hey nice to meet you. I am a student, my name is %s. I am %d years old.", this.name, this.age));}}// ---------------------End------------------------
public class FinalKeyWord {public static void main(String[] args) {Student student = new Student();student.setAge(18);student.setName("张三");student.sayHello();}
}

第3关：抽象类

java">package step3;// ---------------------Begin------------------------abstract class Studenta {abstract void sayHello();
}
class Student extends Person {String name="jack";int age=18;public Student(int age,String name){super(age,name);}public  void sayHello() {System.out.println(String.format("大家好，我叫%s，今年%d岁，很高兴认识大家", this.name,this.age));}public static void main(String[] args) {
Student s=new Student();
s.sayHello();}
}// ---------------------End------------------------

第4关：接口

java">package step4;// ---------------------Begin------------------------interface MyInterface{void sayHi();}class InterfaceDemo implements Demo{public void show(){System.out.println("实现了接口中的show方法");}
}// ---------------------End------------------------

第5关：多态

java">package step5;// ---------------------Begin------------------------
class Cat extends Animal{public void shout(){System.out.println("小花猫喵喵叫");}
}
class Dog extends Animal{public void shout(){System.out.println("大黄狗汪汪叫");}
}class Pig extends Animal{public void shout(){System.out.println("大胖猪喊喊叫");}
}// ---------------------End------------------------class polymorphicDemo{public static void main(String[] args){Cat c = new Cat();Dog d = new Dog();method(c);method(d);method(new Pig());}public static void method(Animal a){a.shout();}}

第6关：匿名内部类

java">package step6;abstract class Demo{abstract void show();
}// ---------------------Begin------------------------class Outer{public void show(){System.out.println("外部类调用show方法");}void method(){new Demo(){void show(){System.out.println("内部类调用show方法");} }.show();}
}// ---------------------End------------------------

第7关：Lambda表达式

java">package step7;
import java.util.Scanner;interface Mycaculator{int add(int a, int b);
}public class LambdaTest {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int a = scanner.nextInt();int b = scanner.nextInt();// ---------------------Begin------------------------//lambad表达式实现Mycaculator接口完成两数相加并打印输出结果Mycaculator calculator = (x,y)->x+y;int result = calculator.add(a,b);System.out.print(result);// ---------------------End------------------------}
}

第8关：异常处理

java">package step8;public class ErrorHandle {public static void main(String[] args) {ErrorHandle errorHandle = new ErrorHandle();// ---------------------Begin------------------------//捕获errorSrc对象中divideTest方法中的除零异常（ArithmeticException）,获取异常信息可以使用getMessage方法try{errorHandle.divideTest();}catch (ArithmeticException e){System.out.println("Exception Messaage:"+e.getMessage());}finally {System.out.println("/ by zero");System.out.println("成功捕获除零异常");}}
public void divideTest() {try {int result = 0 / 1; } catch (ArithmeticException e) {System.out.println("Exception Message: " + e.getMessage());throw e; }}
}