用缓冲字节流，复制一个照片

package d01_TestInput;/*
 * zt
 * 2020/8/7
 * 12:02
 *边读边写
 */

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class CopyFiel {
    public static void main(String[] args) throws Exception {
        //1.创建缓冲流
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream("e:\\aaa\\1.jpg"));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("e:\\aaa\\2.jpg"));
        //2.边读编写
        byte[] buf = new byte[1024];
        int len = 0;
        while((len=bis.read(buf))!=-1){
            //bos.write(buf,0,len); 0 len 保证两个文件大小一样，要不然复制后的文件会超过源文件
            bos.write(buf,0,len);
            bos.flush();
        }
        //关闭
        bis.close();
        bos.close();
        System.out.println("赋值完毕");
    }
}

赋值完毕

Process finished with exit code 0

//bos.write(buf,0,len); 0 len 保证两个文件大小一样，要不然复制后的文件会超过源文件
            bos.write(buf,0,len);