如何使用Java流从Web获取PDF文件 [英] How to get PDF file from web using java streams

问题描述

我需要从网上下载PDF文件，例如http://www.math.uni-goettingen.de/zirkel/loesungen/blatt15/loes15.pdf此链接.我必须使用Streams做到这一点.有了图片，它对我来说效果很好:

I need to download PDF file from web, for example http://www.math.uni-goettingen.de/zirkel/loesungen/blatt15/loes15.pdf this link. I have to do it using Streams. With images it works fine by me :

public static void main(String[] args) {
        try {           
                //get the url page from the arguments array
                String arg = args[0];
                URL url = new URL("https://cs7065.vk.me/c637923/v637923205/25608/AD8WhOSx1ic.jpg");

                try{
                    //jpg
                    InputStream in = new BufferedInputStream(url.openStream());
                    ByteArrayOutputStream out = new ByteArrayOutputStream();
                    byte[] buf = new byte[131072];
                    int n = 0;
                    while (-1!=(n=in.read(buf)))
                    {
                       out.write(buf, 0, n);
                    }
                    out.close();
                    in.close();
                    byte[] response = out.toByteArray();
                    FileOutputStream fos = new FileOutputStream("borrowed_image.jpg");
                    fos.write(response);
                    fos.close();
                 }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

但是使用PDf则不起作用.可能是什么问题?

But with PDf it does not work. What could be the problem ?

推荐答案

我对您的代码进行了较小的编辑，以修复语法错误，这似乎可行(如下).考虑将close()语句放在finally块中.

I made minor edits to your code to fix syntax errors and, this seems to work (below). Consider placing your close() statements in a finally block.

package org.snb;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;

public class PdfTester {
    public static void main(String[] args) {
        //get the url page from the arguments array

        try{
            //String arg = args[0];
            URL url = new URL("http://www.pdf995.com/samples/pdf.pdf");
            //jpg
            InputStream in = new BufferedInputStream(url.openStream());
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            byte[] buf = new byte[131072];
            int n = 0;
            while (-1!=(n=in.read(buf)))
            {
               out.write(buf, 0, n);
            }
            out.close();
            in.close();
            byte[] response = out.toByteArray();
            FileOutputStream fos = new FileOutputStream("/tmp/bart.pdf");
            fos.write(response);
            fos.close();
         }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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