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返回值问题

迎月兮 2022-01-16 阅读 67

1.具体类

class Demo{
  
    public boolean compare(int a,int b ){
        return  a==b ;
    }
}
//Student类
class Student{
    public void study(){
        System.out.println("Good Good Study,Day Day Up!!");
    }
}
//StudentDemo
class StudentDemo{
    public Student method(){

        return  new Student() ;
    }
}

public class ReturnDemo1 {
    public static void main(String[] args) {
        
        Demo d =new Demo() ;
        boolean flag = d.compare(10,10 );
        System.out.println(flag) ;
        System.out.println("--------------------------") ;

        StudentDemo sd = new StudentDemo() ;
        Student student = sd.method(); 
        student.study() ;

    }

2.抽象类

abstract  class Teacher{ 
   public abstract  void teach() ;
}

//TeacherDemo
class TeacherDemo{
    public Teacher function(){
        return  new EnglishTeacher() ;
    }
}

//抽象类的子类存在
class EnglishTeacher extends  Teacher{

    @Override
    public void teach() {
        System.out.println("英语老师教英语...");
    }
}

//测试类
public class ReturnDemo2 {
    public static void main(String[] args) {
        //访问的TeacherDemo类的function方法,返回值是什么?
        TeacherDemo td = new TeacherDemo() ;
        Teacher teacher = td.function();//function方法的本质就是new 子类对象();
        teacher.teach();
    }
}

3.接口

interface Love{
    void love() ;
}
class LoveDemo{
    public Love show(){
        return  new LoveImpl() ;
    }
}
//定义子实现类
class LoveImpl implements  Love{

    @Override
    public void love() {
        System.out.println("爱生活,爱Java");
    }
}

//测试类
public class ReturnDemo3 {
    public static void main(String[] args) {
      
        LoveDemo ld = new LoveDemo() ;
        Love love = ld.show();//show()方法的本质就是new  接口的子实现类对象() ; 接口多态
        love.love();
    }
}
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