I am writing a handler in my spring boot application to convert object into CSV . If the user wants only header , only CSV header should be returned. there are two other options - header_and_body and body_only.
for some reason, header_only returns only empty file. Why is that ? I tried to add p.println() for the header_only option, still only empty file is returned
The complete code is below: Well not complete , I kept getting this error in Stack Overflow " It looks like your post is mostly code; please add some more details." So I removed few irrelevant code for the topic under discussion.
public class CsvHttpMessageConverter extends AbstractHttpMessageConverter<CsvResponse> {
#Override
protected void writeInternal(CsvResponse response, HttpOutputMessage output)
throws IOException, HttpMessageNotWritableException {
output.getHeaders().setContentType(MEDIA_TYPE);
output.getHeaders().set("Content-Disposition", "attachment; filename=\"" + response.getFilename() + "\"");
OutputStream out = output.getBody();
writeRecords(response, out, response.getOption());
out.close();
}
private void writeRecords(CsvResponse response, OutputStream out, String option) throws IOException {
PrintWriter p = new PrintWriter(out);
List<DynamicMarketData> list = response.getRecords();
String header = mdhTotemConfiguration.getColumnListForCommodities();
if (option.equals("header_only") || option.equals("header_and_body"))
{
p.print(header);
}
if (option.equals("body_only") || option.equals("header_and_body"))
{
for (DynamicMarketData elem : list) {
p.println();
Iterator<Map.Entry<String, String>> entries = elem.getDynamicMarketData().entrySet().iterator();
do {
Map.Entry<String, String> entry = entries.next();
p.print(entry.getValue());
if (entries.hasNext() == true)
p.print(",");
} while (entries.hasNext());
}
}
}
}
Related
So I am using Java for my Server and Angular for the Client. I am currently working on a feature where you can select multiple files from a table and when you press on download, it generates a zip file and downloads it to your browser. As of right now, the server now creates the zip file and I can access it in the server files. All that is left to do is to make it download on the client's browser. (the zip file is deleted after the client downloads it)
After doing some research, I found out that you can use a fileOutputStream to do this. I also saw some tools like retrofit... I am using REST and this is what my code looks like. How would I achieve my goal as simply as possible?
Angular
httpGetDownloadZip(target: string[]): Observable<ServerAnswer> {
const params = new HttpParams().set('target', String(target)).set('numberOfFiles', String(target.length));
const headers = new HttpHeaders().set('token', this.tokenService.getStorageToken());
const options = {
headers,
params,
};
return this.http
.get<ServerAnswer>(this.BASE_URL + '/files/downloadZip', options)
.pipe(catchError(this.handleError<ServerAnswer>('httpGetZip')));
}
Java zipping method
public void getDownloadZip(String[] files, String folderName) throws IOException {
[...] // The method is huge but basically I generate a folder called "Download/" in the server
// Zipping the "Download/" folder
ZipUtil.pack(new File("Download"), new File("selected-files.zip"));
// what do I return ???
return;
}
Java context
server.createContext("/files/downloadZip", new HttpHandler() {
#Override
public void handle(HttpExchange exchange) throws IOException {
if (!handleTokenPreflight(exchange)) { return; }
System.out.println(exchange.getRequestURI());
Map<String, String> queryParam = parseQueryParam(exchange.getRequestURI().getQuery());
String authToken = exchange.getRequestHeaders().getFirst("token");
String target = queryParam.get("target") + ",";
String[] files = new String[Integer.parseInt(queryParam.get("numberOfFiles"))];
[...] // I process the data in this entire method and send it to the previous method that creates a zip
Controller.getDownloadZip(files, folderName);
// what do I return to download the file on the client's browser ????
return;
}
});
A possible approach to successfully download your zip file can be the described in the following paragraphs.
First, consider returning a reference to the zip file obtained as the compression result in your downloadZip method:
public File getDownloadZip(String[] files, String folderName) throws IOException {
[...] // The method is huge but basically I generate a folder called "Download/" in the server
// Zipping the "Download/" folder
File selectedFilesZipFile = new File("selected-files.zip")
ZipUtil.pack(new File("Download"), selectedFilesZipFile);
// return the zipped file obtained as result of the previous operation
return selectedFilesZipFile;
}
Now, modify your HttpHandler to perform the download:
server.createContext("/files/downloadZip", new HttpHandler() {
#Override
public void handle(HttpExchange exchange) throws IOException {
if (!handleTokenPreflight(exchange)) { return; }
System.out.println(exchange.getRequestURI());
Map<String, String> queryParam = parseQueryParam(exchange.getRequestURI().getQuery());
String authToken = exchange.getRequestHeaders().getFirst("token");
String target = queryParam.get("target") + ",";
String[] files = new String[Integer.parseInt(queryParam.get("numberOfFiles"))];
[...] // I process the data in this entire method and send it to the previous method that creates a zip
// Get a reference to the zipped file
File selectedFilesZipFile = Controller.getDownloadZip(files, folderName);
// Set the appropiate Content-Type
exchange.getResponseHeaders().set("Content-Type", "application/zip");
// Optionally, if the file is downloaded in an anchor, set the appropiate content disposition
// exchange.getResponseHeaders().add("Content-Disposition", "attachment; filename=selected-files.zip");
// Download the file. I used java.nio.Files to copy the file contents, but please, feel free
// to use other option like java.io or the Commons-IO library, for instance
exchange.sendResponseHeaders(200, selectedFilesZipFile.length());
try (OutputStream responseBody = httpExchange.getResponseBody()) {
Files.copy(selectedFilesZipFile.toPath(), responseBody);
responseBody.flush();
}
}
});
Now the problem is how to deal with the download in Angular.
As suggested in the previous code, if the resource is public or you have a way to manage your security token, including it as a parameter in the URL, for instance, one possible solution is to not use Angular HttpClient but an anchor with an href that points to your ever backend handler method directly.
If you need to use Angular HttpClient, perhaps to include your auth tokens, then you can try the approach proposed in this great SO question.
First, in your handler, encode to Base64 the zipped file contents to simplify the task of byte handling (in a general use case, you can typically return from your server a JSON object with the file content and metadata describing that content, like content-type, etcetera):
server.createContext("/files/downloadZip", new HttpHandler() {
#Override
public void handle(HttpExchange exchange) throws IOException {
if (!handleTokenPreflight(exchange)) { return; }
System.out.println(exchange.getRequestURI());
Map<String, String> queryParam = parseQueryParam(exchange.getRequestURI().getQuery());
String authToken = exchange.getRequestHeaders().getFirst("token");
String target = queryParam.get("target") + ",";
String[] files = new String[Integer.parseInt(queryParam.get("numberOfFiles"))];
[...] // I process the data in this entire method and send it to the previous method that creates a zip
// Get a reference to the zipped file
File selectedFilesZipFile = Controller.getDownloadZip(files, folderName);
// Set the appropiate Content-Type
exchange.getResponseHeaders().set("Content-Type", "application/zip");
// Download the file
byte[] fileContent = Files.readAllBytes(selectedFilesZipFile.toPath());
byte[] base64Data = Base64.getEncoder().encode(fileContent);
exchange.sendResponseHeaders(200, base64Data.length);
try (OutputStream responseBody = httpExchange.getResponseBody()) {
// Here I am using Commons-IO IOUtils: again, please, feel free to use other alternatives for writing
// the base64 data to the response outputstream
IOUtils.write(base64Data, responseBody);
responseBody.flush();
}
}
});
After that, use the following code in you client side Angular component to perform the download:
this.downloadService.httpGetDownloadZip(['target1','target2']).pipe(
tap((b64Data) => {
const blob = this.b64toBlob(b64Data, 'application/zip');
const blobUrl = URL.createObjectURL(blob);
window.open(blobUrl);
})
).subscribe()
As indicated in the aforementioned question, b64toBlob will look like this:
private b64toBlob(b64Data: string, contentType = '', sliceSize = 512) {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, {type: contentType});
return blob;
}
Probably you will need to slightly modify the httpGetDownloadZip method in your service to take into account the returned base 64 data - basically, change ServerAnswer to string as the returned information type:
httpGetDownloadZip(target: string[]): Observable<string> {
const params = new HttpParams().set('target', String(target)).set('numberOfFiles', String(target.length));
const headers = new HttpHeaders().set('token', this.tokenService.getStorageToken());
const options = {
headers,
params,
};
return this.http
.get<string>(this.BASE_URL + '/files/downloadZip', options)
.pipe(catchError(this.handleError<ServerAnswer>('httpGetZip')));
}
You could try using responseType as arraybuffer.
Eg:
return this.http.get(URL_API_REST + 'download?filename=' + filename, {
responseType: 'arraybuffer'
});
In My Project including both front end (angular) and back end (java).
We used the below solution ( hope it work for you ):
Angular:
https://github.com/eligrey/FileSaver.js
let observable = this.downSvc.download(opts);
this.handleData(observable, (data) => {
let content = data;
const blob = new Blob([content], { type: 'application/pdf' });
saveAs(blob, file);
});
Java:
public void download(HttpServletRequest request,HttpServletResponse response){
....
response.setHeader("Content-Disposition",
"attachment;filename=\"" + fileName + "\"");
try (
OutputStream os = response.getOutputStream();
InputStream is = new FileInputStream(file);) {
byte[] buf = new byte[1024];
int len = 0;
while ((len = is.read(buf)) > -1) {
os.write(buf, 0, len);
}
os.flush();
}
You can still use HttpServletRequest on the server...
Then get its OutputStream and write to it.
#RequestMapping(method = RequestMethod.POST , params="action=downloadDocument")
public String downloadDocument(#RequestParam(value="documentId", required=true) String documentId,
HttpServletRequest request,
HttpServletResponse response )
{
try {
String docName = null;
String documentSavePath = getDocumentSavePath();
PDocument doc = mainService.getDocumentById(iDocumentId);
if(doc==null){
throw new RuntimeException("document with id: " + documentId + " not found!");
}
docName = doc.getName();
String path = documentSavePath + ContextUtils.fileSeperator() + docName;
response.setHeader("Content-Disposition", "inline;filename=\"" + docName + "\"");
OutputStream out = response.getOutputStream();
response.setContentType("application/word");
FileInputStream stream = new FileInputStream(path);
IOUtils.copy(stream, out);
out.flush();
out.close();
} catch(FileNotFoundException fnfe){
logger.error("Error downloading document! - document not found!!!! " + fnfe.getMessage() , fnfe);
} catch (IOException e) {
logger.error("Error downloading document!!! " + e.getMessage(),e);
}
return null;
}
First, I want to say thanks to everyone that took their time to help me figure this out because I was searching for more than a week for a solution to my problem. Here it is:
My goal is to start a custom workflow in Alfresco Community 5.2 and to set some custom properties in the first task trough a web script using only the Public Java API. My class is extending AbstractWebScript. Currently I have success with starting the workflow and setting properties like bpm:workflowDescription, but I'm not able to set my custom properties in the tasks.
Here is the code:
public class StartWorkflow extends AbstractWebScript {
/**
* The Alfresco Service Registry that gives access to all public content services in Alfresco.
*/
private ServiceRegistry serviceRegistry;
public void setServiceRegistry(ServiceRegistry serviceRegistry) {
this.serviceRegistry = serviceRegistry;
}
#Override
public void execute(WebScriptRequest req, WebScriptResponse res) throws IOException {
// Create JSON object for the response
JSONObject obj = new JSONObject();
try {
// Check if parameter defName is present in the request
String wfDefFromReq = req.getParameter("defName");
if (wfDefFromReq == null) {
obj.put("resultCode", "1 (Error)");
obj.put("errorMessage", "Parameter defName not found.");
return;
}
// Get the WFL Service
WorkflowService workflowService = serviceRegistry.getWorkflowService();
// Build WFL Definition name
String wfDefName = "activiti$" + wfDefFromReq;
// Get WorkflowDefinition object
WorkflowDefinition wfDef = workflowService.getDefinitionByName(wfDefName);
// Check if such WorkflowDefinition exists
if (wfDef == null) {
obj.put("resultCode", "1 (Error)");
obj.put("errorMessage", "No workflow definition found for defName = " + wfDefName);
return;
}
// Get parameters from the request
Content reqContent = req.getContent();
if (reqContent == null) {
throw new WebScriptException(Status.STATUS_BAD_REQUEST, "Missing request body.");
}
String content;
content = reqContent.getContent();
if (content.isEmpty()) {
throw new WebScriptException(Status.STATUS_BAD_REQUEST, "Content is empty");
}
JSONTokener jsonTokener = new JSONTokener(content);
JSONObject json = new JSONObject(jsonTokener);
// Set the workflow description
Map<QName, Serializable> params = new HashMap();
params.put(WorkflowModel.PROP_WORKFLOW_DESCRIPTION, "Workflow started from JAVA API");
// Start the workflow
WorkflowPath wfPath = workflowService.startWorkflow(wfDef.getId(), params);
// Get params from the POST request
Map<QName, Serializable> reqParams = new HashMap();
Iterator<String> i = json.keys();
while (i.hasNext()) {
String paramName = i.next();
QName qName = QName.createQName(paramName);
String value = json.getString(qName.getLocalName());
reqParams.put(qName, value);
}
// Try to update the task properties
// Get the next active task which contains the properties to update
WorkflowTask wfTask = workflowService.getTasksForWorkflowPath(wfPath.getId()).get(0);
// Update properties
WorkflowTask updatedTask = workflowService.updateTask(wfTask.getId(), reqParams, null, null);
obj.put("resultCode", "0 (Success)");
obj.put("workflowId", wfPath.getId());
} catch (JSONException e) {
throw new WebScriptException(Status.STATUS_BAD_REQUEST,
e.getLocalizedMessage());
} catch (IOException ioe) {
throw new WebScriptException(Status.STATUS_BAD_REQUEST,
"Error when parsing the request.",
ioe);
} finally {
// build a JSON string and send it back
String jsonString = obj.toString();
res.getWriter().write(jsonString);
}
}
}
Here is how I call the webscript:
curl -v -uadmin:admin -X POST -d #postParams.json localhost:8080/alfresco/s/workflow/startJava?defName=nameOfTheWFLDefinition -H "Content-Type:application/json"
In postParams.json file I have the required pairs for property/value which I need to update:
{
"cmprop:propOne" : "Value 1",
"cmprop:propTwo" : "Value 2",
"cmprop:propThree" : "Value 3"
}
The workflow is started, bpm:workflowDescription is set correctly, but the properties in the task are not visible to be set.
I made a JS script which I call when the workflow is started:
execution.setVariable('bpm_workflowDescription', 'Some String ' + execution.getVariable('cmprop:propOne'));
And actually the value for cmprop:propOne is used and the description is properly updated - which means that those properties are updated somewhere (on execution level maybe?) but I cannot figure out why they are not visible when I open the task.
I had success with starting the workflow and updating the properties using the JavaScript API with:
if (wfdef) {
// Get the params
wfparams = {};
if (jsonRequest) {
for ( var prop in jsonRequest) {
wfparams[prop] = jsonRequest[prop];
}
}
wfpackage = workflow.createPackage();
wfpath = wfdef.startWorkflow(wfpackage, wfparams);
The problem is that I only want to use the public Java API, please help.
Thanks!
Do you set your variables locally in your tasks? From what I see, it seems that you define your variables at the execution level, but not at the state level. If you take a look at the ootb adhoc.bpmn20.xml file (https://github.com/Activiti/Activiti-Designer/blob/master/org.activiti.designer.eclipse/src/main/resources/templates/adhoc.bpmn20.xml), you can notice an event listener that sets the variable locally:
<extensionElements>
<activiti:taskListener event="create" class="org.alfresco.repo.workflow.activiti.tasklistener.ScriptTaskListener">
<activiti:field name="script">
<activiti:string>
if (typeof bpm_workflowDueDate != 'undefined') task.setVariableLocal('bpm_dueDate', bpm_workflowDueDate);
if (typeof bpm_workflowPriority != 'undefined') task.priority = bpm_workflowPriority;
</activiti:string>
</activiti:field>
</activiti:taskListener>
</extensionElements>
Usually, I just try to import all tasks for my custom model prefix. So for you, it should look like that:
import java.util.Set;
import org.activiti.engine.delegate.DelegateExecution;
import org.activiti.engine.delegate.DelegateTask;
import org.apache.log4j.Logger;
public class ImportVariables extends AbstractTaskListener {
private Logger logger = Logger.getLogger(ImportVariables.class);
#Override
public void notify(DelegateTask task) {
logger.debug("Inside ImportVariables.notify()");
logger.debug("Task ID:" + task.getId());
logger.debug("Task name:" + task.getName());
logger.debug("Task proc ID:" + task.getProcessInstanceId());
logger.debug("Task def key:" + task.getTaskDefinitionKey());
DelegateExecution execution = task.getExecution();
Set<String> executionVariables = execution.getVariableNamesLocal();
for (String variableName : executionVariables) {
// If the variable starts by "cmprop_"
if (variableName.startsWith("cmprop_")) {
// Publish it at the task level
task.setVariableLocal(variableName, execution.getVariableLocal(variableName));
}
}
}
}
What my application is doing is creating a large csv file (its a report) and the idea is to deliver the contents of the csv file without actually saving a file for it. Here's my code
String csvData; //this is the string that contains the csv contents
byte[] csvContents = csvData.getBytes();
response.contentType = "text/csv";
response.headers.put("Content-Disposition", new Header(
"Content-Disposition", "attachment;" + "test.csv"));
response.headers.put("Cache-Control", new Header("Cache-Control",
"max-age=0"));
response.out.write(csvContents);
ok();
The csv files that are being generated are rather large and the error i am getting is
org.jboss.netty.handler.codec.frame.TooLongFrameException: An HTTP line is larger than 4096 bytes.
Whats the best way to overcome this issue?
My tech stack is java 6 with play framework 1.2.5.
Note: the origin of the response object is play.mvc.Controller.response
Please use
ServletOutputStream
like
String csvData; //this is the string that contains the csv contents
byte[] csvContents = csvData.getBytes();
ServletOutputStream sos = response.getOutputStream();
response.setContentType("text/csv");
response.setHeader("Content-Disposition", "attachment; filename=test.csv");
sos.write(csvContents);
We use this to show the results of an action directly in the browser,
window.location='data:text/csv;charset=utf8,' + encodeURIComponent(your-csv-data);
I am not sure about the out of memory error but I would at least try this:
request.format = "csv";
renderBinary(new ByteArrayInputStream(csvContents));
Apparently netty complains that the http-header is too long - maybe it somehow thinks that your file is part of the header, see also
http://lists.jboss.org/pipermail/netty-users/2010-November/003596.html
as nylund states, using renderBinary should do the trick.
We use writeChunk oursleves to output large reports on the fly, like:
Controller:
public static void getReport() {
final Report report = new Report(code, from, to );
try {
while (report.hasMoreData()) {
final String data = await(report.getData());
response.writeChunk(data);
}
} catch (final Exception e) {
final Throwable cause = e.getCause();
if (cause != null && cause.getMessage().contains("HTTP output stream closed")) {
logger.warn(e, "user cancelled download");
} else {
logger.error(e, "error retrieving data");
}
}
}
in report code
public class Report {
public Report(final String code, final Date from, final Date to) {
}
public boolean hasMoreData() {
// find out if there is more data
}
public Future<String> getData() {
final Job<String> queryJob = new Job<String>() {
#Override
public String doJobWithResult() throws Exception {
// grab data (e.g read form db) and return it
return data;
}
};
return queryJob.now();
}
}
I am working on spring hibernate and I want to import an excel file. I want to make a check on extensions so that no one can upload a file other than excel i.e. restrict the import to files with one of these extensions: xls or xlsx. My code is here:
public class ImportCandidatesFormController extends BNUAbstractFormController {
private ImportCandidatesBL importCandidatesBL;
private ExcelReader reader;
#Override
protected ModelAndView processFormSubmission(HttpServletRequest request,
HttpServletResponse response, Object command, BindException arg3)
throws Exception {
FileUploadVO vo = (FileUploadVO) command;
MultipartFile file = vo.getFile();
System.out.println("File Uploaded: " + file.getOriginalFilename());
boolean isSuccessful = importCandidatesBL.importAndSaveCandidates(
file.getInputStream(),
SessionUtil.getCurrentUser(request.getSession()));
return new ModelAndView(new RedirectView("importCandidates.do?s=1"));
}
public ImportCandidatesBL getImportCandidatesBL() {
return importCandidatesBL;
}
public void setImportCandidatesBL(ImportCandidatesBL importCandidatesBL) {
this.importCandidatesBL = importCandidatesBL;
}
}
String lowercaseFileName = file.getOriginalFilename().toLowerCase();
if (!(lowerCaseFileName.endsWith(".xls") || lowerCaseFileName.endsWith(".xlsx"))) {
// reject file
}
We need to add some code to be executed on application load in order to validate that all the messages.properties elements are well defined for all languages.
Is this possible?
Steps: dynamically read on application load all the spring message codes from JSP or java classes then pass through all message resources properties files and validate that nothing is missing from them.
We ended up doing this manually but without using any library.
Steps:
have all the keys used in Java classes or JSP defined in a constant file
Read them using Java .class properties:
Field[] fields = Constants.class.getFields();
String filed[i].get(Constants.class);
Read all messageResources.properties file names from the project using:
String pathToThisClass = MessageResourcesValidator.class.getProtectionDomain().getCodeSource().getLocatin().getPath();
File filePath = new File(pathToThisClass);
String[] list = filePath.list(new DirFilter("(messages).*\\.(properties)"));
DirFilter is a normal class implementing Java's FileNameFilter
Create a class that read the properties from a file using its file name:
public class PropertiesFile{
private Properties prop;
public PropertiesFile(String fileName) throws Exception
{
init(fileName);
}
private void init(String fileName) throws Exception
{
prop = new Properties();
try (InputStream input = getClass().getClassLoader().getResourceAsStream(fileName);)
{
if(input == null)
{
throw new Exception("Enable to load properties file " + fileName);
}
prop.load(input);
}
catch(IOException e)
{
throw new Exception("Error loading properties file " + fileName);
}
}
public List<String> getPropertiesKeysList()
{
List<String> result = new ArrayList<>();
Enumeration<?> e = prop.propertyNames();
while(e.hasMoreElements())
{
result.add((String) e.nextElement());
// String value = prop.getProperty(key);
}
return result;
}
}
The part that does the comparison should be something as the following code that calls the above methods:
List<String> msgResourcesFiles = getMessageResourcesFileNames();
List<String> codeKeys = getListOfCodeMessageResources();
PropertiesFile file = null;
List<String> propKeys = null;
for(String fileName : msgResourcesFiles)
{
file = new PropertiesFile(fileName);
propKeys = file.getPropertiesKeysList();
for(String key : codeKeys)
{
if(!propKeys.contains(key))
{
throw new Exception("Missing key " + key);
}
}
}
Note: or another workaround would be to compare all message resources files to a default one and this way we minimize the code needed from the above explanation.