Java 回调函数callback 用法

Posted 2023-01-21 dream_heheda

参考 Java学习之Java实现CallBack功能

 

1.定义回调函数接口

里面包含一个方法

public interface CallBack 
	
	public void execute();

2.定义回调函数的实现 

public class BookCallBack implements CallBack

	private String bookName;  	
	 private String author;
	 
	public String getBookName() 
		return bookName;
	
	public void setBookName(String bookName) 
		this.bookName = bookName;
	
	public String getAuthor() 
		return author;
	
	public void setAuthor(String author) 
		this.author = author;
	

	@Override
	public void execute() 
		this.bookName = "The little prince";
		this.author = "Antoine";
 		System.out.println("---------callback实现类 bookName=="+ this.bookName +"      author==="+this.author);
	

3.定义业务处理类

业务处理类里的方法形参传入CallBack接口。

业务处理类里的方法内容包括：处理业务和执行回调函数。

//业务处理类
public class TestBookCallBack 
	
	public void test(CallBack callBack)
		
		//1.处理业务
		System.out.println("---------业务处理类 TestBookCallBack---------");
		//2.执行回调函数
		callBack.execute(); 
	

4.1 定义主函数-使用匿名内部类 实现callback

import org.junit.Test;

public class Main 

	@Test
	public void main() 

		TestBookCallBack testBookCallBack = new TestBookCallBack();
		testBookCallBack.test(new CallBack() 
			@Override
			public void execute() 
				System.out.println("-------------------Anonymous Inner Class-------------------");
			
		);
	

 执行结果为

---------业务处理类 TestBookCallBack---------
---------Anonymous Inner Class--------- 

4.2定义主函数，使用callback的实现类 实现callback

import org.junit.Test;

public class Main 
 
	@Test
	public void main() 

		TestBookCallBack testBookCallBack = new TestBookCallBack();
		BookCallBack bookCallBack = new BookCallBack();
		testBookCallBack.test(bookCallBack);
		System.out.println("---------main---------在主函数中 获取callback实现类里定义的变量值----------" + bookCallBack.getBookName()+"----"+ bookCallBack.getAuthor());

	
 

执行结果

---------业务处理类 TestBookCallBack---------
---------callback实现类 bookName==The little prince      author===Antoine
---------main---------在主函数中 获取callback实现类里定义的变量值----------The little prince----Antoine