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Android 文件下载302的问题，下载地址重定向
在安卓开发中经常需要用到文件下载功能，很多的时候会用基础的写法去写，比如
URL httpUrl = new URL(url.replaceAll(" ", "%20"));
HttpURLConnection http = (HttpURLConnection) httpUrl.openConnection();
http.setConnectTimeout(5 * 1000);
http.setRequestMethod("GET");
http.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); //设置客户端可以接受的返回数据类型
http.setRequestProperty("Accept-Language", "zh-CN"); //设置客户端使用的语言问中文
http.setRequestProperty("Charset", "UTF-8"); //设置通信编码为UTF-8
http.setRequestProperty("Accept-Connection", "identity");
http.setRequestProperty("Range", "bytes=" + startPos + "-");
http.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); //客户端用户代理
http.setRequestProperty("Connection", "Keep-Alive"); //使用长连接
inStream = http.getInputStream();
用这种写法，在url是文件的直接地址时没有问题。但是，当url是带有统计或者其他功能的地址，在我们访问时被转发了之后。
http.getResponseCode()就会返回302。并且http.getContentLength()为0。
这是因为我们没有访问到文件的真正地址。
所以需要url重定向，
inStream = http.getInputStream();
if(http.getResponseCode() == 302){
inStream = reconnection(http.getHeaderField("Location"),startPos, infoBean);
}
private InputStream reconnection(String url,long startPos, DownloadGameInfoBean infoBean){
try {
URL httpUrl = new URL(url.replaceAll(" ", "%20"));
HttpURLConnection http = (HttpURLConnection) httpUrl.openConnection();
http.setConnectTimeout(5 * 1000);
http.setRequestMethod("GET");
http.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); //设置客户端可以接受的返回数据类型
http.setRequestProperty("Accept-Language", "zh-CN"); //设置客户端使用的语言问中文
http.setRequestProperty("Charset", "UTF-8"); //设置通信编码为UTF-8
http.setRequestProperty("Accept-Connection", "identity");
http.setRequestProperty("Range", "bytes=" + startPos + "-");
http.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); //客户端用户代理
http.setRequestProperty("Connection", "Keep-Alive"); //使用长连接
//http.getContentLength()获得从startPos开始到结尾的长度,所以要加上startPos才是总长度
infoBean.setEndPos(http.getContentLength() + startPos);
return http.getInputStream();
}catch (Exception e){
e.printStackTrace();
}
return null;
}
这样无论地址是否是最终的文件地址，就都可以访问到文件地址了
在安卓开发中经常需要用到文件下载功能，很多的时候会用基础的写法去写，比如
URL httpUrl = new URL(url.replaceAll(" ", "%20"));
HttpURLConnection http = (HttpURLConnection) httpUrl.openConnection();
http.setConnectTimeout(5 * 1000);
http.setRequestMethod("GET");
http.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); //设置客户端可以接受的返回数据类型
http.setRequestProperty("Accept-Language", "zh-CN"); //设置客户端使用的语言问中文
http.setRequestProperty("Charset", "UTF-8"); //设置通信编码为UTF-8
http.setRequestProperty("Accept-Connection", "identity");
http.setRequestProperty("Range", "bytes=" + startPos + "-");
http.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); //客户端用户代理
http.setRequestProperty("Connection", "Keep-Alive"); //使用长连接
inStream = http.getInputStream();
用这种写法，在url是文件的直接地址时没有问题。但是，当url是带有统计或者其他功能的地址，在我们访问时被转发了之后。
http.getResponseCode()就会返回302。并且http.getContentLength()为0。
这是因为我们没有访问到文件的真正地址。
所以需要url重定向，
inStream = http.getInputStream();
if(http.getResponseCode() == 302){
inStream = reconnection(http.getHeaderField("Location"),startPos, infoBean);
}
private InputStream reconnection(String url,long startPos, DownloadGameInfoBean infoBean){
try {
URL httpUrl = new URL(url.replaceAll(" ", "%20"));
HttpURLConnection http = (HttpURLConnection) httpUrl.openConnection();
http.setConnectTimeout(5 * 1000);
http.setRequestMethod("GET");
http.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); //设置客户端可以接受的返回数据类型
http.setRequestProperty("Accept-Language", "zh-CN"); //设置客户端使用的语言问中文
http.setRequestProperty("Charset", "UTF-8"); //设置通信编码为UTF-8
http.setRequestProperty("Accept-Connection", "identity");
http.setRequestProperty("Range", "bytes=" + startPos + "-");
http.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); //客户端用户代理
http.setRequestProperty("Connection", "Keep-Alive"); //使用长连接
//http.getContentLength()获得从startPos开始到结尾的长度,所以要加上startPos才是总长度
infoBean.setEndPos(http.getContentLength() + startPos);
return http.getInputStream();
}catch (Exception e){
e.printStackTrace();
}
return null;
}
这样无论地址是否是最终的文件地址，就都可以访问到文件地址了