java实现下载器（以及创建一个URL对象)

package DownLoadDemo;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.RandomAccess;

public class DownLoaderTest {
    private static final int MAX_SIZE_BUFF = 1024 * 1024 * 10;     //1MB大小
    //网络视频路径
    private static String path = "https://www.iqiyi.com/v_uggavqs43w.html";
    private static String writePath = "111.mp4";
    public static void main(String[] args) throws IOException {
        //网络协议对象（远程对象）
        HttpURLConnection urlConnection = null;
        //定位网络资源
        URL url = new URL(path);
        //调用url的openConnection（）连接远程对象
        urlConnection = (HttpURLConnection) url.openConnection();
        //设置远程对象的参数和属性:"Range" : 范围，" 0-":没有终止字节数，支持断点续传 
        urlConnection.setRequestProperty("Range", "bytes=0-");
        //发送连接请求，实现真正的连接
        urlConnection.connect();
        //通过返回码，判断是否连接成功(200以内是成功的)
        int code = urlConnection.getResponseCode();
        if(code / 100 != 2) {    //请求失败
            throw new RuntimeException("请求失败，返回码:" + code + "错误");
        }
        //远程对象连接成功后，创建远程对象输入流
        InputStream inputStream = urlConnection.getInputStream();
        //创建bufferedInputStream
//        BufferedInputStream bInStream = new BufferedInputStream(inputStream);
//        //使用RandomAccess工具类
//        RandomAccessFile randomAccess = new RandomAccessFile(path, "rw");
        //创建缓冲字节数组buff
        byte[] buff = null;
        //开始读写
        //1、添加（小技术）打印下载进度（下载的"每块字节"字节数/时间）
        //获取文件大小
        int fileSize = urlConnection.getContentLength();
        System.out.println(fileSize);
        int downloadedCount = 0;
        while(downloadedCount < fileSize) {
            //分块，处理一下最后剩余不足MAX_SIZE_BUFF量
            if(fileSize - downloadedCount > MAX_SIZE_BUFF) {
                buff = new byte[MAX_SIZE_BUFF];
            }else {
                buff = new byte[fileSize - downloadedCount];
            }
            
            int currCount = 0;
            int read = -1;
            long startTime = System.currentTimeMillis();            
//            //读取
//            bInStream.read(buff);
            while(currCount < buff.length) {
                read = inputStream.read();
                if(read == -1) {
                    break;
                }
                buff[currCount++] = (byte)read;
            }
            if(read == -1) {
                break;
            }
            long endTime = System.currentTimeMillis();
            double speed = currCount / ((endTime - startTime) / 1000.0);    //速度b/s
            System.out.println("读取速度:" + speed);
            downloadedCount += currCount;
        }
    
    }
}