java - 下载/保存可直接从给定 URL 获取的文件

Question

我有类似 this link 的链接，直接询问保存的文件名，然后在浏览器中开始下载。

如何以编程方式下载或保存此文件？

我尝试了以下方法:

static void DownloadFile(String url, String fileName) throws MalformedURLException, IOException
{
    url = "http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=DESCRIBE+<"+ url +">&format=text%2Fcsv";
    URL link = new URL(url); //The file that you want to download

    InputStream in = new BufferedInputStream(link.openStream());
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    byte[] buf = new byte[1024];
    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(fileName);
    fos.write(response);
    fos.close();
    System.out.println("Finished");
}

但这会将仅第一行的文件保存为““主语”，“谓语”，“宾语”“而不是完整的文件。

编辑:

按照答案中的建议，我尝试了以下操作，但这也只给出了文件的第一行:

static void DownloadFile(String s_url, String fileName) throws MalformedURLException, IOException
{
    s_url = "http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=DESCRIBE+<"+ s_url +">&format=text%2Fcsv";
    //url = "http://dbpedia.org/data/Sachin_Tendulkar.rdf";
    try {   
        URL url = new URL(s_url); //The file that you want to download

        // read text returned by server
        BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
        PrintWriter out = new PrintWriter(fileName);

        String line;
        while ((line = in.readLine()) != null) {
            out.println(line);
        }
        in.close();
        out.close();
    }
    catch (MalformedURLException e) {
        System.out.println("Malformed URL: " + e.getMessage());
    }
    catch (IOException e) {
        System.out.println("I/O Error: " + e.getMessage());
    }
    System.out.println("Finished");
}

编辑:

我也尝试过使用 Apache FileUtils，但这也只给出了文件的第一行。

static void DownloadFile(String s_url, String fileName) throws MalformedURLException, IOException
{
    s_url = "http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=DESCRIBE+<"+ s_url +">&format=text%2Fcsv";
    URL url = new URL(s_url); //The file that you want to download
    FileUtils.copyURLToFile(url, new File(fileName));
    System.out.println("Finished");
}

Answer 1

如果您想下载文件，Apache Commons 正是您想要的东西，效果非常好!

org.apache.commons.io.FileUtils.copyURLToFile(new URL("URL")), new File("path/to/file"));

如果 url 返回文本，您可以尝试如下操作:

 try {   
        URL url = new URL("http://www.google.com:80/");

        // read text returned by server
        BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
        PrintWriter out = new PrintWriter("filename.txt");

        String line;
        while ((line = in.readLine()) != null) {
            out.println(line);
        }
        in.close();
        out.close();
    }
    catch (MalformedURLException e) {
        System.out.println("Malformed URL: " + e.getMessage());
    }
    catch (IOException e) {
        System.out.println("I/O Error: " + e.getMessage());
    }