Develop Reference

Generated zip file is always corrupted after download on Mac

Lets say that I have a collection of objects which I would like to wrap with zip. My zip conversion class looks like:
public class ZipFile {
public byte[] createZipByteArray(String fileName, byte[] content) throws IOException {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
try (byteArrayOutputStream; ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream)) {
zipOutputStream.setLevel(Deflater.NO_COMPRESSION);
ZipEntry zipEntry = new ZipEntry(fileName);
zipOutputStream.putNextEntry(zipEntry);
zipOutputStream.write(content);
zipOutputStream.closeEntry();
zipOutputStream.flush();
}
return byteArrayOutputStream.toByteArray();
}
}
My controller looks like:
#GetMapping(value = "objectWithDetails/zip", produces = "application/zip")
#RolesAllowed("QUERY_DATA")
public ResponseEntity<byte[]> getObjectWithDetails(String limit, HttpServletResponse response) throws IOException {
response.setContentType("application/zip");
List<ObjectSpecification> objectRepresentation = recipeService.getObjectRepresentation(limit);
byte[] objectsBytes = objectMapper.writeValueAsBytes(objectRepresentation);
ZipFile zipFile = new ZipFile();
return ResponseEntity
.ok()
.contentType(MediaType.valueOf("application/zip"))
.header("Content-Encoding", "UTF-8")
.header("Content-Disposition", String.format("attachment; filename=\"details_%s.zip\"", dateTimeProvider.nowDate()))
.body(zipFile.createZipByteArray(String.format("details_%s.zip", dateTimeProvider.nowDate()), objectsBytes));
}
In swagger, I have a download option for the generated zip files. After all, when I try to open the downloaded file I receive the following:
Unable to expand filename.zip. It is in an unsupported format.
I tried closing ZipOutputStream and ByteArrayOutputStream in a different configuration. Applied a different option for the content type in the controller but still, I cannot find out why all zip files are corrupted. I will be grateful for suggestions on what I miss. Cheers!

I managed to find out the root cause with #k314159
, namely, I had a zip file wrapped with a zip file. New version which works as expected.
public static byte[] createZipByteArray(String fileName, byte[] content) throws IOException {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
try (byteArrayOutputStream; ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream)) {
zipOutputStream.setLevel(Deflater.DEFLATED);
ZipEntry zipEntry = new ZipEntry(fileName);
zipOutputStream.putNextEntry(zipEntry);
zipOutputStream.write(content);
zipOutputStream.closeEntry();
zipOutputStream.flush();
}
return byteArrayOutputStream.toByteArray();
}
and controller
#GetMapping(value = "objectWithDetails", produces = "application/zip")
#RolesAllowed("QUERY_DATA")
public ResponseEntity<byte[]> getObjectWithDetails(String limit, HttpServletResponse response) throws IOException {
response.setContentType("application/zip");
List<ObjectSpecification > objectRepresentation = objectService.getObjectRepresentation(limit);
byte[] objectsBytes = objectMapper.writeValueAsBytes(objectRepresentation);
return ResponseEntity
.ok()
.contentType(MediaType.valueOf("application/zip"))
.header("Content-Encoding", "UTF-8")
.header("Content-Disposition", getObjectFileName("attachment; filename=objects_"))
.body(createZipByteArray(getObjectFileName("objects_"), objectsBytes));
}

How get instance of HttpServletResponse for download files with JAVA EE

I have a file txt on the server (previously generated). When user clicks on button it generates the file, now I want (additionally) download the file inside my function. But I can't make it work(I'm new on JAVA EE), cause I don't know how to get HttpServletResponse.
From web I call function with this:
#Path("getreport")
#POST
#Consumes(MediaType.APPLICATION_JSON)
#Produces(MediaType.APPLICATION_JSON)
public JSONObject getreport(CommonInput input) {
JSONObject j = objectmapper.conertValue(reportBean.getreport(),JSONObject.class);
return j;
}
reprotBean has function:
public void getreport() {
//...doing many things
//generating my file
List<String> lines = new ArrayList<>();
lines.add("star file");
//..adding many lines
Path file = Paths.get("C:\\Users\\myuser\\file.txt");
Files.write(file, lines, StandardCharsets.UTF_8);
downloadFile();
//...doing many things
}
I found this way to download my file:
public void downloadFile(HttpServletResponse response){
String sourceFile = ""C:\\Users\\myuser\\file.txt"";
try {
FileInputStream inputStream = new FileInputStream(sourceFile);
String disposition = "attachment; fileName=outputfile.txt";
response.setContentType("text/txt");
response.setHeader("Content-Disposition", disposition);
response.setHeader("content-Length", String.valueOf(stream(inputStream, response.getOutputStream())));
} catch (IOException e) {
logger.error("Error occurred while downloading file {}",e);
}
}
private long stream(InputStream input, OutputStream output) throws IOException {
try (ReadableByteChannel inputChannel = Channels.newChannel(input); WritableByteChannel outputChannel = Channels.newChannel(output)) {
ByteBuffer buffer = ByteBuffer.allocate(10240);
long size = 0;
while (inputChannel.read(buffer) != -1) {
buffer.flip();
size += outputChannel.write(buffer);
buffer.clear();
}
return size;
}
}
When I try to use downloadFile(), it requires HttpServletResponse, and I don't have that parameter. I can't understand how to get that (how it works), or do I have to use another method for download my file?
All solutions I found requires HttpServletResponse (download files from browsers)

If you have that file generated already. Just need write it to HttpServletResponse
resp.setContentType("text/plain");
resp.setHeader("Content-disposition", "attachment; filename=sample.txt");
try(InputStream in = req.getServletContext().getResourceAsStream("sample.txt");
OutputStream out = resp.getOutputStream()) {
byte[] buffer = new byte[ARBITARY_SIZE];
int numBytesRead;
while ((numBytesRead = in.read(buffer)) > 0) {
out.write(buffer, 0, numBytesRead);
}
}
Be sure to make your file to be accessed by ServeletContext
If you are using Spring Rest framework. Can refer to below
#GetMapping("/download")
public ResponseEntity<byte[]> downloadErrorData() throws Exception {
List<Employee> employees = employeeService.getEmployees();
ObjectMapper objectMapper = new ObjectMapper();
String json = objectMapper.writeValueAsString(employees);
byte[] isr = json.getBytes();
String fileName = "employees.json";
HttpHeaders respHeaders = new HttpHeaders();
respHeaders.setContentLength(isr.length);
respHeaders.setContentType(new MediaType("text", "json"));
respHeaders.setCacheControl("must-revalidate, post-check=0, pre-check=0");
respHeaders.set(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + fileName);
return new ResponseEntity<byte[]>(isr, respHeaders, HttpStatus.OK);
}
credit to: https://www.jeejava.com/file-download-example-using-spring-rest-controller/

corrupt pdf file while writing the bytes to stream

Facing a problem while implementing a java-ws service for downloading a pdf file from another webservice. Below is the piece of code for the same.decode() is used because of the webservice(this java code is invoking) is responding with encoded binary-base-64. I could see the PDF is downloaded in the given location but when i open with pdf reader, it says the file is corrupt. Could you please help me ?
public DownloadFileResponse DownloadResponseMapper(Header header, DownloadDocumentResponseType response){
DownloadFileResponse result = new DownloadFileResponse();
result.setHeader(header);
Status status = new Status();
status.setStatusCode(String.valueOf(String.valueOf(response.getStatus().getStatusCode())));
status.setStatusMessage(response.getStatus().getMessage());
result.setStatus(status);
if(String.valueOf(String.valueOf(String.valueOf(response.getStatus().getStatusCode()))) != "0") {
String qNameFile = FileExchange.getProperty("fileSystem.sharedLocation") + "/" + "result.pdf";
try {
byte[] fileContent = FileUtil.decode(response.getFile());
System.out.println(response.getFile());
FileUtil.writeByteArraysToFile(qNameFile, fileContent);
} catch (Exception e) {
_logger.info(e.getStackTrace());
}
// calculate the hash of the file using two algorithm SHA-256/SHA-512
List<FileHashType> hashes = FileUtil.calculateHash(result.getFile());
result.setFileHash(hashes);
}
return result;
}
public static void writeByteArraysToFile(String fileName, byte[] content) throws IOException {
File file = new File(fileName);
BufferedOutputStream writer = new BufferedOutputStream(new FileOutputStream(file));
writer.write(content);
writer.flush();
writer.close();
}

Spring REST - create ZIP file and send it to the client

I want to create a ZIP file that contains my archived files that I received from the backend, and then send this file to a user. For 2 days I have been looking for the answer and can't find proper solution, maybe you can help me :)
For now, the code is like this (I know I shouldn't do it all in the Spring controller, but don't care about that, it is just for testing purposes, to find the way to make it works):
#RequestMapping(value = "/zip")
public byte[] zipFiles(HttpServletResponse response) throws IOException {
// Setting HTTP headers
response.setContentType("application/zip");
response.setStatus(HttpServletResponse.SC_OK);
response.addHeader("Content-Disposition", "attachment; filename=\"test.zip\"");
// Creating byteArray stream, make it bufferable and passing this buffer to ZipOutputStream
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(byteArrayOutputStream);
ZipOutputStream zipOutputStream = new ZipOutputStream(bufferedOutputStream);
// Simple file list, just for tests
ArrayList<File> files = new ArrayList<>(2);
files.add(new File("README.md"));
// Packing files
for (File file : files) {
// New zip entry and copying InputStream with file to ZipOutputStream, after all closing streams
zipOutputStream.putNextEntry(new ZipEntry(file.getName()));
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream, zipOutputStream);
fileInputStream.close();
zipOutputStream.closeEntry();
}
if (zipOutputStream != null) {
zipOutputStream.finish();
zipOutputStream.flush();
IOUtils.closeQuietly(zipOutputStream);
}
IOUtils.closeQuietly(bufferedOutputStream);
IOUtils.closeQuietly(byteArrayOutputStream);
return byteArrayOutputStream.toByteArray();
}
But the problem is, that using the code, when I enter the URL localhost:8080/zip, I get a file test.zip.html instead of .zip file.
When I remove .html extension and leave just test.zip it opens correctly. So my questions are:
How to avoid returning this .html extension?
Why is it added?
I have no idea what else can I do. I was also trying replace ByteArrayOuputStream with something like:
OutputStream outputStream = response.getOutputStream();
and set the method to be void so it returns nothing, but It created .zip file which was damaged?
On my MacBook after unpacking the test.zip I was getting test.zip.cpgz which was again giving me test.zip file and so on.
On Windows the .zip file was damaged as I said and couldn't even open it.
I also suppose, that removing .html extension automatically will be the best option, but how?
Hope it is no as hard as It seems to be :)
Thanks

The problem is solved.
I replaced:
response.setContentType("application/zip");
with:
#RequestMapping(value = "/zip", produces="application/zip")
And now I get a clear, beautiful .zip file.
If any of you have either better or faster proposition, or just want to give some advice, then go ahead, I am curious.

#RequestMapping(value="/zip", produces="application/zip")
public void zipFiles(HttpServletResponse response) throws IOException {
//setting headers
response.setStatus(HttpServletResponse.SC_OK);
response.addHeader("Content-Disposition", "attachment; filename=\"test.zip\"");
ZipOutputStream zipOutputStream = new ZipOutputStream(response.getOutputStream());
// create a list to add files to be zipped
ArrayList<File> files = new ArrayList<>(2);
files.add(new File("README.md"));
// package files
for (File file : files) {
//new zip entry and copying inputstream with file to zipOutputStream, after all closing streams
zipOutputStream.putNextEntry(new ZipEntry(file.getName()));
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream, zipOutputStream);
fileInputStream.close();
zipOutputStream.closeEntry();
}
zipOutputStream.close();
}

#RequestMapping(value="/zip", produces="application/zip")
public ResponseEntity<StreamingResponseBody> zipFiles() {
return ResponseEntity
.ok()
.header("Content-Disposition", "attachment; filename=\"test.zip\"")
.body(out -> {
var zipOutputStream = new ZipOutputStream(out);
// create a list to add files to be zipped
ArrayList<File> files = new ArrayList<>(2);
files.add(new File("README.md"));
// package files
for (File file : files) {
//new zip entry and copying inputstream with file to zipOutputStream, after all closing streams
zipOutputStream.putNextEntry(new ZipEntry(file.getName()));
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream, zipOutputStream);
fileInputStream.close();
zipOutputStream.closeEntry();
}
zipOutputStream.close();
});
}

I am using REST Web Service of Spring Boot and I have designed the endpoints to always return ResponseEntity whether it is JSON or PDF or ZIP and I came up with the following solution which is partially inspired by denov's answer in this question as well as another question where I learned how to convert ZipOutputStream into byte[] in order to feed it to ResponseEntity as output of the endpoint.
Anyway, I created a simple utility class with two methods for pdf and zip file download
#Component
public class FileUtil {
public BinaryOutputWrapper prepDownloadAsPDF(String filename) throws IOException {
Path fileLocation = Paths.get(filename);
byte[] data = Files.readAllBytes(fileLocation);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.parseMediaType("application/pdf"));
String outputFilename = "output.pdf";
headers.setContentDispositionFormData(outputFilename, outputFilename);
headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
return new BinaryOutputWrapper(data, headers);
}
public BinaryOutputWrapper prepDownloadAsZIP(List<String> filenames) throws IOException {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.parseMediaType("application/zip"));
String outputFilename = "output.zip";
headers.setContentDispositionFormData(outputFilename, outputFilename);
headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
ZipOutputStream zipOutputStream = new ZipOutputStream(byteOutputStream);
for(String filename: filenames) {
File file = new File(filename);
zipOutputStream.putNextEntry(new ZipEntry(filename));
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream, zipOutputStream);
fileInputStream.close();
zipOutputStream.closeEntry();
}
zipOutputStream.close();
return new BinaryOutputWrapper(byteOutputStream.toByteArray(), headers);
}
}
And now the endpoint can easily return ResponseEntity<?> as shown below using the byte[] data and custom headers that is specifically tailored for pdf or zip.
#GetMapping("/somepath/pdf")
public ResponseEntity<?> generatePDF() {
BinaryOutputWrapper output = new BinaryOutputWrapper();
try {
String inputFile = "sample.pdf";
output = fileUtil.prepDownloadAsPDF(inputFile);
//or invoke prepDownloadAsZIP(...) with a list of filenames
} catch (IOException e) {
e.printStackTrace();
//Do something when exception is thrown
}
return new ResponseEntity<>(output.getData(), output.getHeaders(), HttpStatus.OK);
}
The BinaryOutputWrapper is a simple immutable POJO class I created with private byte[] data; and org.springframework.http.HttpHeaders headers; as fields in order to return both data and headers from utility method.

Sending a Zip file to Rest WebService

I'm trying to implement a method in my java based application that involves uploading a zip file to my server. Client is java, server is java (REST , jboss 7) . In the past I successfully managed to upload image files, but now, with a zip file i am having issues and my main doubt is if these issues are client related or server related (or both) .
So , my client looks like this
final HttpHeaders headers = HttpClientUtils.headersJSONAndAcceptJSON();
MultiValueMap<String, Object> requestMap = new LinkedMultiValueMap<String, Object>();
addMap("filename", filename, requestMap);
addMap("contenttype", contentType, requestMap);
addMap("type", type, requestMap);
try {
ByteArrayOutputStream bout = new ByteArrayOutputStream();
int b = -1;
//file data is the inputstream created from the File
while ( (b = filedata.read())>= 0 ) {
bout.write(b);
}
ByteArrayResource rs = new ByteArrayResource( bout.toByteArray() ){
#Override
public String getFilename() {
return "";
}
};
addMap("resource", rs, requestMap);
} catch (IOException e1) {
throw new IllegalStateException("Error");
}
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
headers.setAccept(Arrays.asList(HttpClientUtils.mtypeJSONUtf8()));
final String url = this.baseURL + summaryURL;
try {
ResponseEntity<Summary> rEntity = restTemplate.exchange(
url,
HttpMethod.POST,
HttpClientUtils.entity(headers, requestMap),
Summary.class
(...)
and meanwhile on the server side I have
#POST
#Path("/")
#Consumes(MediaType.MULTIPART_FORM_DATA)
#Produces("application/json; charset=UTF-8")
public Summary addImportedSummary(#MultipartForm FileUploadFormObj imp)
{
Summary importedSummary = new Summary();
Map<String , String> newpath = new HashMap<String, String>();
if(imp.getFileData() != null)
{
ZipInputStream zip = new ZipInputStream(imp.getFileData());
ZipEntry entry;
try {
while ((entry = zip.getNextEntry()) != null)
{
if(entry.getName().endsWith(".html") || entry.getName().endsWith(".htm"))
{
if(entry.getSize() > 0)
{
StringWriter writer = new StringWriter();
IOUtils.copy(zip, writer, "UTF-8");
String content = writer.toString();
//do something with the content
}
}
}
zip.close();
} catch (IOException e) {
throw new BadRequestException("Error " + e);
}
}
The problem happens when I try to copy the file content with IOUtils or any other reader. I always get the exception
ZipException too many length or distance symbols
Now, I think the problem might be in the way I am sending the data due to the file being a zip but I don't know exactly where the problem is. Did everyone ever ran into a similar problem?