Develop Reference

Download File to Downloads Folder From Server ActionForward/Struts/Java

I am trying to download a file from my web application in an ActionForward java class. I have looked at many examples to try different solutions but none have worked so far. My knowledge is limited and have spent a good amount of time to get this to work.
From my jsp page a link hits an action in my struts config which takes the thread to an ActionForward return type method on a java class.
I then take the passed in file name and grab it from an amazon s3 bucket. With the file downloaded from the s3 bucket I now have the file bytes[].
I need to then have the file download to the local machine as most files do (appearing in the downloads folder and the web showing the download at the bottom bar of the page)
After following some examples I kept getting this error
Servlet Exception - getOutputStream() has already been called for this
response
I got past the error by doing
response.getOutputStream().write
Instead of creating a new OutputStream like this
OutputStream out = response.getOutputStream();
Now it runs without errors but no file gets downloaded.
Here is the java file I am attempting to do this in.
As you can see in the file below is a commented out DownloadServlet class which I tried as another attempt. I did this because a lot of the examples have classes the extends HttpServlet which I made DownloadServlet extend but it made no difference.
package com.tc.fms.actions;
import com.sun.media.jai.util.PropertyUtil;
import com.tc.fw.User;
import org.apache.commons.beanutils.PropertyUtils;
import java.io.*;
import java.io.File;
import java.util.ArrayList;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.tc.fw.actions.BaseAction;
import org.apache.struts.upload.FormFile;
import io.isfs.utils.ObjectUtils;
import com.tc.fw.*;
import com.tc.fms.*;
import com.tc.fms.service.*;
public class FileDownloadAction extends BaseAction {
private static ObjectUtils objectUtils = new ObjectUtils();
private final int ARBITARY_SIZE = 1048;
public ActionForward performWork(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
System.out.println("In File Download Action");
ActionMessages errors = new ActionMessages();
User user = (User)request.getSession().getAttribute(User.lookupKey);
String fileName = (String) PropertyUtils.getSimpleProperty(form, "fileName");
String outboundDir = (String) PropertyUtils.getSimpleProperty(form, "outboundDir");
System.out.println("File Dir: " + outboundDir + " File Name: " + fileName);
try{
try {
// Get file from amazon
byte[] fileBytes = objectUtils.getFileDavid(outboundDir, fileName);
if (fileBytes != null) {
java.io.File file = File.createTempFile(fileName.substring(0, fileName.lastIndexOf(".") - 1), fileName.substring(fileName.lastIndexOf(".")));
FileOutputStream fileOuputStream = new FileOutputStream(file);
fileOuputStream.write(fileBytes);
try {
/* DownloadServlet downloadServlet = new DownloadServlet();
downloadServlet.doGet(request, response, file);*/
response.setContentType("text/plain");
response.setHeader("Content-disposition", "attachment; filename=" + file.getName());
InputStream in = new FileInputStream(file);
/*OutputStream out = response.getOutputStream();*/
byte[] buffer = new byte[ARBITARY_SIZE];
int numBytesRead;
while ((numBytesRead = in.read(buffer)) > 0) {
response.getOutputStream().write(buffer, 0, numBytesRead);
}
} catch (Exception e) {
System.out.println("OutputStream EROOR: " + e);
}
} else {
System.out.println("File Bytes Are Null");
errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage("fms.download.no.file.found"));
saveErrors(request, errors);
return mapping.findForward("failure");
// Failed
}
} catch (Exception eee){
System.out.println("Failed in AWS ERROR: " + eee);
errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage("fms.download.failed"));
saveErrors(request, errors);
return mapping.findForward("failure");
}
}catch (Exception ee){
System.out.println("Failed in global try");
errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage("fms.download.failed"));
saveErrors(request, errors);
return mapping.findForward("failure");
}
return mapping.findForward("success");
}
}

copy file from res/raw to sd on first run

I have a problem with the below code it will copy a file to internal sd. It works the problem is it will only work the second time I run the app. I need it to copy on first run I have no idea what I am doing wrong can anyone please help.
private void CopyPak()
{
try {
InputStream in = getResources().openRawResource(R.raw.bor);
File outFolder = new File(Environment.getExternalStorageDirectory() + "/OpenBOR/Paks");
File outFile = new File(outFolder, "bor.pak");
if(!outFolder.exists()){
outFolder.mkdir();
}
FileOutputStream out = new FileOutputStream(outFile);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (IOException e) {
Log.e("tag", "Failed to copy asset file: ", e);
}
}
private void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
}
Here are the required imports.
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;

Found the error I had to replace mkdir with mkdirs as I was making more than one folder.

Download a files from FTP matching a wildcard using Java Apache Commons Net

Basically I need to download list of matching files for the search from a FTP server. I have the code to download a specific file from a FTP server. But I need to download all the matching files with my wildcard search. How is that possible in Java?
Here is code for file downloading of a specific filename, from a FTP server -
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
public class FTPDownloadFileDemowithoutmodandfilefilter {
public static void main(String[] args) {
String server = "test.rebex.net";
int port = 21;
String user = "demo";
String pass = "password";
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
ftpClient.login(user, pass);
ftpClient.enterLocalPassiveMode();
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
File localFile = new File("C:\\project\\readme1.txt");
FTPFile remoteFile = ftpClient.mdtmFile("/readme.txt");
if (remoteFile != null)
{
OutputStream outputStream =
new BufferedOutputStream(new FileOutputStream(localFile));
if (ftpClient.retrieveFile(remoteFile.getName(), outputStream))
{
System.out.println("File downloaded successfully.");
}
outputStream.close();
localFile.setLastModified(remoteFile.getTimestamp().getTimeInMillis());
}
} catch (IOException ex) {
System.out.println("Error: " + ex.getMessage());
ex.printStackTrace();
} finally {
try {
if (ftpClient.isConnected()) {
ftpClient.logout();
ftpClient.disconnect();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}

Use FTPClient.mlistDir (recommended, if the server supports it) or
FTPClient.listFiles to retrieve list of files. And then filter them according to your needs.
The following example downloads all files matching a regular expression .*\.jpg:
FTPFile[] remoteFiles = ftpClient.listFiles(remotePath);
Pattern pattern = Pattern.compile(".*\\.jpg");
Stream<FTPFile> matchingFiles =
Arrays.stream(remoteFiles).filter(
(FTPFile remoteFile) -> pattern.matcher(remoteFile.getName()).matches());
for (Iterator<FTPFile> iter = matchingFiles.iterator(); iter.hasNext(); ) {
FTPFile remoteFile = iter.next();
System.out.println("Found file " + remoteFile.getName() + ", downloading ...");
File localFile = new File(localPath + "\\" + remoteFile.getName());
OutputStream outputStream =
new BufferedOutputStream(new FileOutputStream(localFile));
if (ftpClient.retrieveFile(remotePath + "/" + remoteFile.getName(), outputStream))
{
System.out.println(
"File " + remoteFile.getName() + " downloaded successfully.");
}
outputStream.close();
}

Example of POST request in Android studio

I just started learning android few days ago and I have a problem with uploading my JSON data to server. I manage to retrieve it via following code:
Edit: I did manage to retrieve files using external OKHTTP library but I would like to do this without using external libraries.
package cc.demorest;
import android.os.AsyncTask;
import android.renderscript.ScriptGroup;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(R.layout.activity_main);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask task = new DownloadTask();
task.execute("myserver.com");
}
//Downloadtask
public class DownloadTask extends AsyncTask<String,Void,String> {
#Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection=null;
try {
url = new URL(urls[0]);
urlConnection=(HttpURLConnection)url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data=reader.read();
while (data !=-1){
char current=(char) data;
result += current;
data = reader.read();
}
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
//After download task
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
JSONArray jArray=new JSONArray(result);
JSONObject json_data = jArray.getJSONObject(1);
//Logging data
Log.i("Podatci: ", "Id: " + json_data.getInt("Id") +
", Name: " + json_data.getString("Name") +
", Years: " + json_data.getString("Age") +
", Email address: " + json_data.getString("Email")
);
TextView textView = (TextView) findViewById(R.id.textViewName);
textView.setText("ID: "+", Name: "+ json_data.getInt("Id")+json_data.getString("Name")+json_data.getString("Age")+json_data.getString("Email"));
/*
String data = jsonObject.getString("Name");
Log.i("Website content", data);
*/
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
I am now trying to send my data to same server with same fields. I searched internet but most things that I found are outdated.. I would really appriciate some help or example.
Best Regards

Use HttpURLConnection, it does not use external libraries. If you're going to use an HttpURLConnection, it needs to be an AsyncTask.
Here is my code from a project I completed. Hope it helps.
First, put this in your manifest.xml file before :
<uses-permission android:name="android.permission.INTERNET" />
Calling the AsyncTask:
(Ignore the this, SinceTime, and GoesAddress. They are just variables I passed in)
URL url = new URL("https://eddn.usgs.gov/cgi-bin/fieldtest.pl");
new ReceiveData(this, SinceTime, GoesAddress).execute(url);
The Class:
package com.ryan.scrapermain;
import android.content.Context;
import android.os.AsyncTask;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;
import javax.net.ssl.HttpsURLConnection;
public class ReceiveData extends AsyncTask<URL, Integer, Long> {
String response = "";
String SinceTime;
String GoesAddress;
Context myContext;
ReceiveData(Context context, String since, String goes) {
this.myContext = context;
SinceTime = since;
GoesAddress = goes;
}
private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException {
StringBuilder feedback = new StringBuilder();
boolean first = true;
for(Map.Entry<String, String> entry : params.entrySet()){
if (first)
first = false;
else
feedback.append("&");
feedback.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
feedback.append("=");
feedback.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
}
return feedback.toString();
}
public void getData() throws IOException {
HashMap<String, String> params = new HashMap<>();
params.put("DCPID", GoesAddress);
params.put("SINCE", SinceTime);
URL url = new URL("https://eddn.usgs.gov/cgi-bin/fieldtest.pl");
HttpURLConnection client = null;
try {
client = (HttpURLConnection) url.openConnection();
client.setRequestMethod("POST");
// You need to specify the context-type. In this case it is a
// form submission, so use "multipart/form-data"
client.setRequestProperty("multipart/form-data", "https://eddn.usgs.gov/fieldtest.html;charset=UTF-8");
client.setDoInput(true);
client.setDoOutput(true);
OutputStream os = client.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(getPostDataString(params));
writer.flush();
writer.close();
os.close();
int responseCode = client.getResponseCode();
if (responseCode == HttpsURLConnection.HTTP_OK) {
String line;
BufferedReader br = new BufferedReader(new InputStreamReader(client.getInputStream()));
while ((line = br.readLine()) != null) {
response += line;
}
}
else {
response = "";
}
}
catch (MalformedURLException e){
e.printStackTrace();
}
finally {
if(client != null) // Make sure the connection is not null.
client.disconnect();
}
}
#Override
protected Long doInBackground(URL... params) {
try {
getData();
} catch (IOException e) {
e.printStackTrace();
}
// This counts how many bytes were downloaded
final byte[] result = response.getBytes();
Long numOfBytes = Long.valueOf(result.length);
return numOfBytes;
}
protected void onPostExecute(Long result) {
System.out.println("Downloaded " + result + " bytes");
// This is just printing it to the console for now.
System.out.println(response);
// In the following two line I pass the string elsewhere and decode it.
InputCode input = new InputCode();
input.passToDisplay(myContext, response);
}
}

Use Volley as defined here. It's far more easier.

Cannot upload a file from Android to PHP server

I am making an application which uploads a file from a SD card to PHP server. Howeverm when I try to do this, I'm getting an error.
My Android code is as below:
package de.fileupload;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.DefaultHttpClient;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import android.os.Bundle;
#SuppressWarnings("unused")
public class FileUpload extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final TextView tmp = (TextView) findViewById(R.id.textView1);
tmp.setText("Hi! Click the button!");
Button b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
File f = new File("mnt/sdcard/SMSBackup.txt");
try {
f.createNewFile();
Date d = new Date();
PrintWriter writer = new PrintWriter(f);
writer.println(d.toString());
writer.close();
HttpClient client = new DefaultHttpClient();
httpPostFileUpload(client, "mnt/sdcard/SMSBackup.txt", "http://10.0.2.2:8080/admin/admin/upload1.php", "uploadedfile");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public void httpPostFileUpload(
HttpClient client,
String filePath,
String uploadUri,
String inputNameAttr) throws ClientProtocolException,
IOException {
HttpUriRequest request = new HttpPost(uploadUri);
MultipartEntity form = new MultipartEntity();
client.getParams().setBooleanParameter("http.protocol.expect-continue", false);
form.addPart(inputNameAttr, new FileBody(new File(filePath)));
((HttpEntityEnclosingRequestBase) request).setEntity(form);
try {
client.execute(request);
} catch (ClientProtocolException e) {
throw e;
} catch (IOException ee) {
throw ee;
}
}
}
and my PHP files are as below:
upload1.php
<meta name="generator" content="Namo WebEditor(Trial)">
<form enctype="multipart/form-data" action="upload.php" method="POST">
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
Choose a file to upload: <input name="uploadedfile" type="file" /><br /><input
type="submit" value="Upload File" />
</form>
<?php
$to_file = "tmp/" . basename($_FILES['uploadedfile']['name']);
$from_file = $_FILES['uploadedfile']['tmp_name'];
if (move_uploaded_file($from_file, $to_file)) {
echo "Successful upload";
?>
<?php echo $to_file;?>
<?php
} else {
echo "Unsuccessful upload";
}
?>
and upload.php is:
<?php
// Where the file is going to be placed
$target_path = "localhost/admin/admin/uploads/";
/* Add the original filename to our target path.
Result is "uploads/filename.extension" */
$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);
if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
echo "The file ". basename( $_FILES['uploadedfile']['name']).
" has been uploaded";
chmod ("uploads/".basename( $_FILES['uploadedfile']['name']), 0644);
} else{
echo "There was an error uploading the file, please try again!";
echo "filename: " . basename( $_FILES['uploadedfile']['name']);
echo "target_path: " .$target_path;
}
?>
Can any one please tell that where i m wrong? It always shows the unsuccessful upload for the file. While my server is running.

Try to use instead move_uploaded_file(), function copy(). They use the same input parameters, like this:
if(copy($_FILES['uploadedfile']['tmp_name'], $target_path)) { ...
Most likely the PHP process has no permissions to move the uploaded file to different folder after successful upload, because the moving contains in essence copy and delete operation.
One more thing - try not to change the permission of the uploaded file to 0644, because this also can be restricted to the PHP process, i.e. when you deal with file system operations on Linux (I assume you use Linux machine for your server) the working process (in your case PHP and apache) has particular permissions set and maybe they do not have ability to delete/move files outside their working folder.
You should also change the uploading folder permission to 755 or 777.

This class allow you to upload file directly. No need to decode your file.
public class Helpher extends AsyncTask<String, Void, String> {
Context context;
JSONObject json;
ProgressDialog dialog;
int serverResponseCode = 0;
DataOutputStream dos = null;
FileInputStream fis = null;
BufferedReader br = null;
public Helpher(Context context) {
this.context = context;
}
protected void onPreExecute() {
dialog = ProgressDialog.show(Main2Activity.this, "ProgressDialog", "Wait!");
}
#Override
protected String doInBackground(String... arg0) {
try {
File f = new File(arg0[0]);
URL url = new URL("http://localhost:8888/imageupload.php");
int bytesRead;
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setUseCaches(false);
conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
String contentDisposition = "Content-Disposition: form-data; name=\"keyValueForFile\"; filename=\""
+ f.getName() + "\"";
String contentType = "Content-Type: application/octet-stream";
dos = new DataOutputStream(conn.getOutputStream());
fis = new FileInputStream(f);
dos.writeBytes(SPACER + BOUNDARY + NEW_LINE);
dos.writeBytes(contentDisposition + NEW_LINE);
dos.writeBytes(contentType + NEW_LINE);
dos.writeBytes(NEW_LINE);
byte[] buffer = new byte[MAX_BUFFER_SIZE];
while ((bytesRead = fis.read(buffer)) != -1) {
dos.write(buffer, 0, bytesRead);
}
dos.writeBytes(NEW_LINE);
dos.writeBytes(SPACER + BOUNDARY + SPACER);
dos.flush();
int responseCode = conn.getResponseCode();
if (responseCode != 200) {
Log.w(TAG,
responseCode + " Error: " + conn.getResponseMessage());
return null;
}
br = new BufferedReader(
new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
Log.d(TAG, "Sucessfully uploaded " + f.getName());
} catch (MalformedURLException e) {
} catch (IOException e) {
} finally {
try {
dos.close();
if (fis != null)
fis.close();
if (br != null)
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return String.valueOf(serverResponseCode);
}
#Override
protected void onPostExecute(String result) {
dialog.dismiss();
}
}
This is the AsyncTask "Helpher" class used for upload image from Android. To call this class use like syntax below.
new Main2Activity.Helpher(this).execute(fileUri.getPath());
Here fileUri.getPath() local image location. If you want to see the server response value is avilable in " StringBuilder sb" you can print sb value