Android HttpURLConnection java.io.FileNotFoundException
如果我连接到似乎是Apache服务器,下面的代码非常有效,但是当我尝试连接到.Net服务器时,它会抛出一个错误。我猜这是一个标题的要求,但我似乎无法得到一个成功的回应,无论我尝试Android HttpURLConnection java.io.FileNotFoundException,android,download,httpurlconnection,filenotfoundexception,Android,Download,Httpurlconnection,Filenotfoundexception,如果我连接到似乎是Apache服务器,下面的代码非常有效,但是当我尝试连接到.Net服务器时,它会抛出一个错误。我猜这是一个标题的要求,但我似乎无法得到一个成功的回应,无论我尝试 public String Download(String Url) { String filepath=null; try { //set the download URL, a url that points to a file on the internet //this is the file to
public String Download(String Url)
{
String filepath=null;
try {
//set the download URL, a url that points to a file on the internet
//this is the file to be downloaded
URL url = new URL(Url);
//create the new connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//set up some things on the connection
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
//and connect!
urlConnection.connect();
//set the path where we want to save the file
//in this case, going to save it on the root directory of the sd card.
File SDCardRoot = Environment.getExternalStorageDirectory();
//create a new file, specifying the path, and the filename
//which we want to save the file as.
String filename= "effortback.png"; // you can download to any type of file ex:.jpeg (image) ,.txt(text file),.mp3 (audio file)
Log.i("Local filename:",""+filename);
File file = new File(SDCardRoot + "/",filename);
//=====================================
if(file.createNewFile())
{
file.createNewFile();
}
//=====================================
//this will be used to write the downloaded data into the file we created
FileOutputStream fileOutput = new FileOutputStream(file);
//this will be used in reading the data from the internet
InputStream inputStream = urlConnection.getInputStream();
//=====================================
//this is the total size of the file
int totalSize = urlConnection.getContentLength();
//variable to store total downloaded bytes
int downloadedSize = 0;
//=====================================
//create a buffer...
byte[] buffer = new byte[2048];
int bufferLength = 0; //used to store a temporary size of the buffer
//now, read through the input buffer and write the contents to the file
while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
//add the data in the buffer to the file in the file output stream (the file on the sd card
fileOutput.write(buffer, 0, bufferLength);
//add up the size so we know how much is downloaded
downloadedSize += bufferLength;
//this is where you would do something to report the prgress, like this maybe
Log.i("Progress:","downloadedSize:"+downloadedSize+"totalSize:"+ totalSize) ;
}
//close the output stream when done
fileOutput.close();
if(downloadedSize==totalSize) filepath=file.getPath();
//catch some possible errors...
} catch (MalformedURLException e) {
e.printStackTrace();
Log.i("URL-ERROR:",e.toString());
} catch (IOException e) {
filepath=null;
e.printStackTrace();
Log.i("IO-ERROR:",e.toString());
}
Log.i("filepath:"," "+filepath) ;
return filepath;
}
urlConnection.setDoOutput(false);
错误范围为:
java.io.FileNotFoundException //I always get this with either one of the below
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1061)
//or this one below
libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionTmpl.java:186)
urlConnection.setDoOutput(false);
看来无论我怎么努力,我都无法使它发挥作用。同样,如果我尝试从谷歌或其他一些网站下载一张图片,但不是全部,但绝对不是我的(.Net)。我错过了什么?请帮助。遇到了相同的问题,如您所说解决了:
urlConnection.setDoOutput(false);
请注意,您必须将其设置为false,因为默认情况下它为true。请注意,您必须将其设置为false,因为
Volley
HurlStack
正在将其设置为true。注意;)
urlConnection.setDoOutput(false);
编辑:
我刚刚检查了代码,默认情况下,正如@Abraham Philip所说的,它是假的。但我必须将其设置为false,因为如果调用getDoOutput()
它将返回true
。我发现Volley
HurlStack
正在将其设置为true。所以,我的结论是,setDoOutput
为false,它会起作用
urlConnection.setDoOutput(false);
package java.net;
public abstract class URLConnection {
...
/**
* Specifies whether this {@code URLConnection} allows sending data.
*/
protected boolean doOutput;
...
public boolean getDoOutput() {
return doOutput;
}
public void setDoOutput(boolean newValue) {
checkNotConnected();
this.doOutput = newValue;
}
如果您的服务器返回=
(400),您可以从HttpUrlConnection
(和OkHttpClient
)获取FileNotFoundException
)。您应该首先检查状态代码,以检查需要读取的流。
urlConnection.setDoOutput(false);
urlConnection.setDoOutput(false);
HttpStatus已弃用。最新语法似乎是:
我遇到了一个问题,执行
HEAD
-请求时抛出了FileNotFoundException
原因是,对
头的响应没有主体,因此调用getInputStream
会抛出FileNotFoundException
urlConnection.setDoOutput(false);
因此,如果您正在执行头
,则不应尝试获取输入流
好的,再深入一点,发现服务器出现403错误。这是一个安全错误,所以现在我的问题是如何克服它?提前谢谢。好的,我想好了。非常重要的是,如果你有同样的问题,不要使用这一行,也要检查你的URL。第一个问题是我的URL拼写错误,所以我得到了服务器的明显响应。在我修复我的URL后,它仍然有问题。最终是这一行:urlConnection.setDoOutput(true);显然,JAVA中的这一行强制http协议将GET更改为POST,而不考虑指定GET。仅供将来参考。谢谢你,这让我忙了一整天。谢谢,请回答你自己的问题@内森,你应该把这个作为你自己问题的答案,然后接受它。根据SO规则,这是完全好的,以前已经做过很多次了。太好了!现在不推荐使用真正有用的HttpStatus。此答案需要更新。请使用HttpURLConnection.HTTPStatus.BAD_请求,HTTPStatus.BAD_请求已从API级别22弃用。如何打印作为参数的内容?第[1608-1624]行的代码您的语句似乎不正确。默认情况下,setDoOutput为false。参考(Java文档):是的,您的回答是正确的,默认情况下为false。检查我的更新;)和+1,因为你变成了OP刚才作为评论提到的答案。
urlConnection.setDoOutput(false);