java - URLConnection inputStream 未被完全读取

Question

我编写了以下代码来从服务器下载一些文件，但问题是这段代码没有读取完整的响应(inputStream)。文件大小为 7.5 MB，而我每次都获得 5.5 MB，当然 adobe reader 提示文件已损坏。这是代码

import java.net.URLConnection;
public class Downloader {
URL url;
public Downloader(){
    try {

        url = new URL("https://d396qusza40orc.cloudfront.net/algs4partI/slides%2F13StacksAndQueues.pdf");
        FileOutputStream outStream;
        ObjectOutputStream oStream;
        try {
            URLConnection con = url.openConnection();
            InputStream inStream = con.getInputStream();
            outStream = new FileOutputStream("data.pdf");
            oStream = new ObjectOutputStream(outStream);
            int bytesRead;
            int totalBytesRead = 0;
            byte[] buffer = new byte[100000];
            while((bytesRead = inStream.read(buffer)) > 0){

                //outStream.write(buffer, 0 , bytesRead);
                oStream.write(buffer, 0, bytesRead);
                buffer = new byte[100000];
                totalBytesRead += bytesRead;
            }
            System.out.println("Total Bytes read are = " + totalBytesRead);
            oStream.close();
            outStream.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}
public static void main(String[] args){
    Downloader d = new Downloader();
}

知道我在这里做错了什么吗？提前致谢。

Answer 1

当您不序列化 Java 对象时，您不希望使用 ObjectOutputStream。

取消注释行

//outStream.write(buffer, 0 , bytesRead);

并删除

oStream.write(buffer, 0, bytesRead);

所以:

while((bytesRead = inStream.read(buffer)) > 0){

    outStream.write(buffer, 0 , bytesRead);           
    buffer = new byte[100000]; // this line is useless
    totalBytesRead += bytesRead;
}

完全摆脱 ObjectOutputStream。您的文件长 5.25 MB(5,511,685 字节)，而不是 7.5 MB。