Question

现在我正在尝试从服务器下载一个文件，使用302将get请求重定向到下载资源。当我使用下面的代码下载文件时服务器响应失败我认为服务器知道我不知道使用浏览器下载文件。当我使用浏览器时，它工作正常，文件是正确的。

你能告诉我我的代码中的问题在哪里。谢谢。

这是我的代码：

@SuppressWarnings("deprecation")
public static void downloadFile(String url, String fileName, String page) throws InterruptedException, IOException {

    httpClient = new DefaultHttpClient(cm);


    // set timeout
    HttpParams httpParams = httpClient.getParams();
    HttpConnectionParams.setSoTimeout(httpParams, TIMEOUT_SECONDS * 1000);

    HttpEntity entity = null;
    HttpGet httpGet = new HttpGet(url);
    Random r=new java.util.Random(UAS.length); 
    //Cookie:AJSTAT_ok_times=7
    String ua = UAS[r.nextInt(UAS.length)];

    httpGet.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
    httpGet.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31 AlexaToolbar/alxg-3.1");
    httpGet.setHeader("Accept-Charset", "UTF-8,utf-8;q=0.7,*;q=0.3");
    httpGet.setHeader("Accept-Encoding", "deflate,sdch");
    httpGet.setHeader("Accept-Language", "zh-CN,zh;q=0.8");
    httpGet.setHeader("Cache-Control", "max-age=0");
    httpGet.setHeader("Connection", "keep-alive");
    httpGet.setHeader("Cookie", "AJSTAT_ok_times=7");
    httpGet.setHeader("Host", "www.test.com");
    httpGet.setHeader("Cookie", "AJSTAT_ok_times=7");


    try {
        HttpContext context = new BasicHttpContext();

        HttpResponse remoteResponse = httpClient.execute(httpGet, context);
        entity = remoteResponse.getEntity();
        if (remoteResponse.getStatusLine().getStatusCode() != 200) {
            System.out.println(remoteResponse.getStatusLine().getStatusCode());
        }
    } catch (Exception e) {
        httpGet.abort();
        e.printStackTrace();
        return;
    }

    // 404返回
    if (entity == null) {
        System.out.println("404");
        return;
    }

    File file = new File(fileOutPutDIR + page + "/" + fileName + ".rar");

    File parent = file.getParentFile();
    if (parent.exists() || parent.mkdirs()) {
        // ...
    } else {
        throw new IOException("Failed to create output directory " + parent);
    }

    System.out.println("downloading..." + file.getName());

    InputStream input = entity.getContent();

    try {
        FileUtils.copyInputStreamToFile(input, file);
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        IOUtils.closeQuietly(input);
    }

}

POM：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.2.3</version>
</dependency>

Answer 1

请查看http文档 http://hc.apache.org/httpclient-legacy/redirects.html 我认为你需要手动处理重定向

手动处理重定向

300和399之间的所有响应代码都是某种形式的重定向响应。最常见的重定向响应代码是：

301 Moved Permanently. HttpStatus.SC_MOVED_PERMANENTLY
302 Moved Temporarily. HttpStatus.SC_MOVED_TEMPORARILY
303 See Other. HttpStatus.SC_SEE_OTHER
307 Temporary Redirect. HttpStatus.SC_TEMPORARY_REDIRECT

注意：3xx范围内有许多响应代码，它们不仅仅指示发送请求的不同URI。下面列出了这些响应代码，它们的处理方式将特定于应用程序。

当您的应用程序收到“简单”重定向响应之一时，它应从HttpMethod对象中提取新URL并从该URL重试下载。此外，在重定向形成递归循环的情况下，限制重定向的数量通常是一个好主意。

可以从Location标题中提取要连接的URL。

    String redirectLocation;
    Header locationHeader = method.getResponseHeader("location");
    if (locationHeader != null) {
        redirectLocation = locationHeader.getValue();
    } else {
        // The response is invalid and did not provide the new location for
        // the resource.  Report an error or possibly handle the response
        // like a 404 Not Found error.
    }

确定新位置后，您可以正常重新尝试连接。有关详细信息，请参阅教程。

从服务器下载文件失败

1 个答案: