Java 回调callback举例详解【java面试】

目录

• 前言
• 1、什么是回调
• 2、例子
• 第一章.故事的缘起
• 第二章.幼师的找茬
• 第三章.幼师回来了
• 第四章.门口的婆婆

public class Student
{
	private String name=null;
	public Student(String name)
	{
		this.name=name;
	}
	public void setName(String name)
	{
		this.name=name;
	}
	private int calcADD(int a,int b)
	{
		return a+b;
	}
	public void fillBlank(int a,int b)
	{
		int result=calcADD(a,b);
		System.out.println(name+"心算:"+a+"+"+b+"="+result);
	}
}

public class Test
{
	public static void main(String[] args)
	{
		int a=1;
		int b=1;
		Student s=new Student("小明");
		s.fillBlank(a,b);
	}
}

public class Calculator
{
	public int add(int a,int b)
	{
		return a+b;
	}
}

public class Student
{
	private String name=null;
	public Student(String name)
	{
		this.name=name;
	}
	public void setName(String name)
	{
		this.name=name;
	}
	private int calcADD(int a,int b)
	{
		return a+b;
	}
	private int useCalculator(int a,int b)
	{
		return new Calculator().add(a,b);
	}
	public void fillBlank(int a,int b)
	{
		int result=useCalculator(a,b);
		System.out.println(name+"使用计算器:"+a+"+"+b+"="+result);
	}
}

public class Test
{
	public static void main(String[] args)
	{
		int a=168;
		int b=291;
		Student s=new Student("小明");
		s.fillBlank(a,b);
	}
}

public class SuperCalculator
{
	public void add(int a,int b,Student xiaoming)
	{
		int result=a+b;
		xiaoming.fillBlank(a,b,result);
	}
}

public class Student
{
	private String name=null;
	public Student(String name)
	{
		this.name=name;
	}
	public void setName(String name)
	{
		this.name=name;
	}
	public void callHelp(int a,int b)
	{
		new SuperCalculator().add(a,b,this);
	}
	public void fillBlank(int a,int b,int result)
	{
		System.out.println(name+"求助小红计算:"+a+"+"+b+"="+result);
	}
}

public class Test
{
	public static void main(String[] args)
	{
		int a=26549;
		int b=16487;
		Student s=new Student("小明");
		s.callHelp(a,b);
	}
}

public interface doJob
{
	public void fillBlank(int a,int b,int result);
}

public class SuperCalulator
{
	public void add(int a,int b doJob customer)
	{
		int result=a+b;
		customer.fillBlank(a,b,result);
	}
}

public class Student
{
	private String name=null;
	public Student(String name)
	{
		this.name=name;
	}
	public class doHomeWork implements doJob
	{
		@Override
		public void fillBlank(int a,int b,int result)
		{
			System.out.println(name+"求助小红计算:"+a+"+"+b+"="+result);
		}
	}
	public void callHelp(int a,int b)
	{
		new SuperCalculator().add(a,b,new doHomeWork());
	}
}

public class Seller
{
	private String name=null;
	public Seller(String name)
	{
		this.name=name;
	}
	public setName(String name)
	{
		this.name=name;
	}
	public class doHomeWork implements doJob
	{
		@Override
		public void fillBlank(int a,int b,int result)
		{
			System.out.println(name+"求助小红算账:"+a+"+"+b+"="+result+"元"；)
		}
	}
	public void callHelp(int a,int b)
	{
		new SuperCalculator().add(a,b,new doHomeWork());
	}
}

public class Test
{
	public static void main(String[] args)
	{
		int a=56;
		int b=31;
		int c=26497;
		int d=11256;
		Student s1=new Student("小明")；
		Seller s2=new Seller("老婆婆")；

		s1.callHelp(a,b);
		s2.callHelp(c,d);
	}
}