使用Java在httpclient中下载文件？

Question

My code is,

import java.io.*;
import java.net.*;

 public class DownloadHttp
 {
public static void main(String a[])
{
    DownloadHttp d  =   new DownloadHttp();
    String addr =   "http://www.gmail.com";
    String file =   "D:/venkatesh/Software/download1.html";
    d.download(addr,file);
}


    public void download(String address, String localFileName) {
   OutputStream out = null;
   URLConnection conn = null;
  InputStream in = null;
   try {
    // Get the URL
    URL url = new URL(address);
    // Open an output stream to the destination file on our local filesystem
    out = new BufferedOutputStream(new FileOutputStream(localFileName));
    conn = url.openConnection();
    in = conn.getInputStream();

    // Get the data
    byte[] buffer = new byte[1024];
    int numRead;
    while ((numRead = in.read(buffer)) != -1) {
        out.write(buffer, 0, numRead);
    }            
    // Done! Just clean up and get out
} catch (Exception exception) {
    exception.printStackTrace();
} finally {
    try {
        if (in != null) {
            in.close();
        }
        if (out != null) {
            out.close();
        }
    } catch (IOException ioe) {
        // Shouldn't happen, maybe add some logging here if you are not 
        // fooling around ;)
    }
  }
 }
 }

Here I wants download specific file using httpClient using java. It produces:

"java.net.ConnectException: Connection timed out: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)" as error.

How to resolve it, help me, thanks in advance.

Answer 1

I believe it is a network problem. Have you tried to access the url directly or are you behind a firewall?

Answer 2

Recompiled your code on my machine, it works perfectly well. I'm able to fetch files from the web.

Check if your web-browser can download the file for you (make sure it's not a network problem)

One thing to notice though, in your finally block you might want to close the streams separately. So if anything goes wrong with the input stream, the output stream will still be closed.

finally {
        try {
            if (in != null) {
                in.close();
            }
        } catch (Exception ignored) {}
        try {
            if (out != null) {
                out.close();
            }
        } catch (Exception ignored) {}
    }

Answer 3

I think you are using a proxy when connecting to internet.

Set these in the code and then retry.

System.setProperty("http.proxyHost", *Proxy-IP*);
System.setProperty("http.proxyPort", *Proxy-Port*);