从Java中的URL读取XML字符串

Question

I am retrieving data from restful web service in XML format, but unfortunately my String is null . Please help me, where is the problem in my code?

Here is the example code:

URL url = new URL("http://loxvo.fogbugz.com/api.asp?cmd=logon&email=myemail&password=mypwd");
HttpURLConnection request1 = (HttpURLConnection) url.openConnection();
request1.setRequestMethod("GET");
request1.connect();
InputStream is = request1.getInputStream();
BufferedReader bf_reader = new BufferedReader(new InputStreamReader(is));
String responseData = IOUtils.toString(bf_reader);
System.out.print(responseData);

I have tried this url in rest client: it's returning me correct xml, but here my String is null .

Answer 1

You can read response like

 BufferedReader bufferedReader = 
     new BufferedReader(new InputStreamReader(request1.getInputStream()));
        String line;
        while ((line = bufferedReader.readLine()) != null) {
          System.out.print(line);
        }

Getting resp 302 your code. Try with

 URL url = new URL("https://loxvo.fogbugz.com/api.asp?cmd=logon&email=myemail&password=mypwd");

Answer 2

Try to just pass the InputStream of the request directly to IOUtils.toString( ), because IOUtils.toString makes buffering on its own.

Additionally you can check with request1.getResponseCode() if the request was successfull or if there was any kind of Http Error.

Furthermore it is not necessary to invoke the connect() method because this is implicitely done within the getInputStream() call.

Update: Getting also Error 302. Of course i d'ont have the correct login data. But the request must work using the following code:

try {
   URL url = new URL("http://loxvo.fogbugz.com/api.asp?cmd=logon&email=myemail&   password=mypwd");
   //URL url = new URL("http://www.google.de");
   HttpURLConnection request1 = (HttpURLConnection) url.openConnection();
   request1.setRequestMethod("GET");
   // request1.connect();
   String code = String.valueOf(request1.getResponseCode());
   System.out.println("Error code "+code);
   InputStream is = request1.getInputStream();

   BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
   String line;
   while ((line = bufferedReader.readLine()) != null) {
     System.out.println(line);
   }
   // BufferedReader bf_reader = new BufferedReader(new InputStreamReader(is));
   // String responseData = IOUtils.toString(bf_reader);
   // System.out.print(responseData);
} catch (Exception e) {
    e.printStackTrace();
}

Answer 3

The problem is the 302 HTTP Error which means that the server performs a redirect.

If you change your URL from HTTP to HTTPS than it works in the expected way. The result of the request is:

OK
Error code 200
<?xml version="1.0" encoding="UTF-8"?><response><error code="1"><![CDATA[Incorrect password or username]]></error></response>

You can get the redirect address by evaluating the response header of the request with the http URL. There you can find the redirect URL by checking the value of the key "Location".

String reUrl = request1.getHeaderField("Location");
System.out.println("Redirect URL "+reUrl);

.

Which leads to to following output:

Found
Error code 302
Redirect URL https://loxvo.fogbugz.com/api.asp?cmd=logon&email=myemail&password=mypwd

Answer 4

Try to convert InputStream to String with Scanner. I tried this code and works fine.

    URL url = new URL("http://loxvo.fogbugz.com/api.asp?cmd=logon&email=myemail&password=mypwd");
    HttpURLConnection request1 = (HttpURLConnection) url.openConnection();
    request1.setRequestMethod("GET");
    request1.connect();
    InputStream is = request1.getInputStream();
    String inputStreamString = new Scanner(is,"UTF-8").useDelimiter("\\A").next();
    System.out.print(inputStreamString);