java基础，传参与返回值

一 参数



1,类名作为参数
package com.ma.demo;
 
 
public class People {
  void show() {
    System.out.println("people show");
  }
}
---
package com.ma.demo;
public class PeopleDemo {
  void method(People p) {
    p.show();
  }
}
---
package com.ma.demo;
public class Test {
  public static void main(String[] args) {
    People p = new People();
    PeopleDemo pd = new PeopleDemo();
    pd.method(p);
  }
}
----



2,抽象类做为参数
package com.ma.demo2;
 
 
abstract class People {
  abstract void show();
}
---
package com.ma.demo2;
public class PeopleDemo {
  void method(People p) {
    p.show();
  }
}
---
package com.ma.demo2;
public class Student extends People {
  @Override
  void show() {
    // TODO Auto-generated method stub
    System.out.println("student show");
  }
}
---
package com.ma.demo2;
public class Test {
  public static void main(String[] args) {
    People p = new Student();
    PeopleDemo pd = new PeopleDemo();
    pd.method(p);
  }
}
------


3,接口做为参数
package com.ma.demo3;
 
 
interface People {
  public abstract void show();
}
---
package com.ma.demo3;
 
 
public class PeopleDemo {
  void method(People p) {
    p.show();
  }
}
---
package com.ma.demo3;
public class Student implements People {
  @Override
  public void show() {
    // TODO Auto-generated method stub
    System.out.println("student show");
  }
}
---
package com.ma.demo3;
public class Test {
  public static void main(String[] args) {
    People p = new Student();
    PeopleDemo pd = new PeopleDemo();
    pd.method(p);
  }
}
------





二.返回值



1,类名作为返回值
package com.ma.demo4;
 
 
public class People {
  void show() {
    System.out.println("people show");
  }
}
---
package com.ma.demo4;
public class PeopleDemo {
  People method() {
    return new People();
  }
}
---
package com.ma.demo4;
public class Test {
  public static void main(String[] args) {
    PeopleDemo pd = new PeopleDemo();
    People p = pd.method();
    p.show();
  }
}
------


2,抽象类作为返回值
package com.ma.demo5;
 
 
abstract class People {
  public abstract void show();
}
---
package com.ma.demo5;
public class PeopleDemo {
  Student method() {
    return new Student();
  }
}
---
package com.ma.demo5;
public class Student extends People {
  @Override
  public void show() {
    // TODO Auto-generated method stub
    System.out.println("student show");
  }
}
---
package com.ma.demo5;
public class Test {
  public static void main(String[] args) {
    PeopleDemo pd = new PeopleDemo();
    People p = pd.method();
    p.show();
  }
}
----


3,接口作为返回值
package com.ma.demo6;
 
 
interface People {
  public abstract void show();
}
--
package com.ma.demo6;
 
 
public class PeopleDemo {
  People method() {
    return new Student();
  }
}
--
package com.ma.demo6;
public class Student implements People {
  @Override
  public void show() {
    // TODO Auto-generated method stub
    System.out.println("student show");
  }
}
----
package com.ma.demo6;
public class Test {
  public static void main(String[] args) {
    PeopleDemo pd = new PeopleDemo();
    People p = pd.method();
    p.show();
  }
}
----


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