We Keep Coding

IOException: Server returned 400 error code

Hi Below is the piece of code. In the below code, when i close writer after write, server gives expected results. But if it is closed in finally block it return 400 bad request. Is there any reason for this behavior?
BufferedReader br = null;
HttpURLConnection conn = null;
OutputStreamWriter writer = null;
String ip = "test"
try {
URL url = new URL(http://someurl));
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setConnectTimeout(0);
conn.setRequestProperty("Content-Type", "application/json");
writer = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
writer.write(ip);
// writer.close();
br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line;
while ((line = br.readLine()) != null) {
jsonString.append(line);
}
} catch (final Exception e) {
LOG.error("Error" + e);
}
finally
{
//Closing writer in finally block.
if(writer != null)
{
try
{
writer.close();
}
catch (IOException e) {
LOG.error("Error in closing Writer", e);
}
}
if (br != null)
{
try
{
br.close();
}
catch (final IOException e)
{
LOG.error("Error: ", e);
}
}
if(conn != null){
conn.disconnect();
}
}

You need to flush the contents to server. Use writer.flush() instead of writer.close() once you are done with writing request, just before reading response.

Java HttpURLConnection invoke remote server and returned 500 status

I want to invoke remote server using HttpURLConnection, here is my function:
public String invokeAwvsServer(String api, String param, String method){
System.out.println(api+param);
BufferedReader reader = null;
HttpURLConnection connection = null;
OutputStreamWriter out = null;
try {
URL url = new URL(api);
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setInstanceFollowRedirects(true);
connection.setRequestMethod(method);
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("X-Auth", apiKey);
connection.connect();
if(method.equalsIgnoreCase("POST")){
out = new OutputStreamWriter(connection.getOutputStream(), "UTF-8");
out.append(param);
out.flush();
}
reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
String line;
StringBuffer res = new StringBuffer();
while ((line = reader.readLine()) != null) {
res.append(line);
}
return res.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(reader != null){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(connection != null){
connection.disconnect();
}
if(out != null){
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return "error";
}
I use this function in its own class and works well, but if I call it in other class ,the remote server return 500 status code and JVM throws exception like:
java.io.IOException: Server returned HTTP response code: 500 for URL:...
What`s the reason?Thanks a lot:)

How can I write an api post request from Java to c#

Recently I needed to move some code from Java to C#.
This is one of the methods that I couldn't rewrite... can someone help me?
public static String coreApiPostRequest(URL url, String input) {
try {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/xml");
String responseMessage=null;
OutputStream os = conn.getOutputStream();
os.write(input.getBytes());
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
os.flush();
if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
throw new RuntimeException("Failed : HTTP error code : "
+ conn.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
while ((output = br.readLine()) != null) {
System.out.println(output);
responseMessage = output;
}
conn.disconnect();
return responseMessage;
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}

Can't send data with the use of POST request from Java to PHP

I am trying to send data from Java code to PHP code with the use of a POST request. For some reason on the PHP side I get nothing at all, but my code "works" (no exception occurs). What can be the problem? Thanks in advance!
My data looks something like this:
"data=" + sb.toString()
And the code can be found here below:
public static void sendRequest(String encryptedString) {
HttpURLConnection connection = null;
BufferedReader br = null;
DataOutputStream dos = null;
try {
connection = (HttpURLConnection) new URL("http://localhost/something/function").openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setFixedLengthStreamingMode(encryptedString.length());
dos = new DataOutputStream(connection.getOutputStream());
dos.writeBytes(encryptedString);
dos.flush();
br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line;
while((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
System.out.println("Can't create connection...");
e.printStackTrace();
} finally {
try {
if(dos != null) dos.close();
if(connection != null) connection.disconnect();
if(br != null) br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
PS: The picture:

The problem was that I encrypted the whole data=randomnumber thing with SHA-1. The data= part should not be encrypted and needs to be added later.

FileNotFoundException on HttpsURLConnection with POST and unmutable doOutput variable

I'm trying to POST some data to an https url, in my android application, in order to get a json format response.
I'm facing two problems:
is = conn.getInputStream();
throws
java.io.FileNotFoundException
I don't get if i do something wrong with HttpsURLConnection.
The second problem arose when i debug the code (used eclipse); I set a breakpoint after
conn.setDoOutput(true);
and, when inspecting conn values, I see that the variable doOutput remain set to false and type GET.
My method for https POST is the following, where POSTData is a class extending ArrayList<NameValuePair>
private static String httpsPOST(String urlString, POSTData postData, List<HttpCookie> cookies) {
String result = null;
HttpsURLConnection conn = null;
OutputStream os = null;
InputStream is = null;
try {
URL url = new URL(urlString);
conn = (HttpsURLConnection) url.openConnection();
conn.setReadTimeout(10000);
conn.setConnectTimeout(15000);
conn.setRequestMethod("POST");
conn.setUseCaches (false);
conn.setDoInput(true);
conn.setDoOutput(true);
if(cookies != null)
conn.setRequestProperty("Cookie",
TextUtils.join(";", cookies));
os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(postData.getPostData());
writer.flush();
writer.close();
is = conn.getInputStream();
BufferedReader r = new BufferedReader(
new InputStreamReader(is));
StringBuilder total = new StringBuilder();
String line;
while ((line = r.readLine()) != null) {
total.append(line);
}
result = total.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
}
}
if (conn != null) {
conn.disconnect();
}
}
return result;
}
A little update: apparently eclipse debug lied to me, running and debugging on netbeans shows a POST connection. Error seems to be related to parameters i'm passing to the url.

FileNotFoundException means that the URL you posted to doesn't exist, or couldn't be mapped to a servlet. It is the result of an HTTP 404 status code.
Don't worry about what you see in the debugger if it doesn't agree with how the program behaves. If doOutput really wasn't enabled, you would get an exception obtaining the output stream.