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How to create multiple csv file from large csv file in Java

I am kind of stuck, I usually know how to create single csv, it looks like I am missing or disconnecting from this code. I am not able to create multiple csv file from Pojo class. The file usually is more than 15mb, but I need to split into multiple csv file like 5mb each. Any suggestion would be great helped. Here is sample code that I am trying but failing.
public static void main(String[] args) throws IOException {
getOrderList();
}
public static void getOrderList() throws IOException {
List<Orders> ordersList = new ArrayList<>();
Orders orders = new Orders();
orders.setOrderNumber("1");
orders.setProductName("mickey");
Orders orders1 = new Orders();
orders1.setOrderNumber("2");
orders1.setProductName("mini");
ordersList.add(orders);
ordersList.add(orders1);
Object [] FILE_HEADER = {"orderNumber","productName"};
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int rowCount = 0;
int fileCount = 1;
try {
BufferedWriter fileWriter = new BufferedWriter(new OutputStreamWriter(byteArrayOutputStream));
CSVPrinter csvFilePrinter = new CSVPrinter(fileWriter,
CSVFormat.DEFAULT.withRecordSeparator("\n"));
csvFilePrinter.printRecord(FILE_HEADER);
for (Orders patient : ordersList) {
rowCount++;
patient.getOrderNumber();
patient.getProductName();
if (rowCount <= 1) {
csvFilePrinter.printRecord(patient);
csvFilePrinter.flush();
}
if (rowCount > 1 ) {
csvFilePrinter.printRecord(patient);
fileCount++;
csvFilePrinter.flush();
}
}
} catch (IOException e) {
throw new RuntimeException("Cannot generate csv file", e);
}
byte[] csvOutput = byteArrayOutputStream.toByteArray();
OutputStream outputStream = null;
outputStream = new FileOutputStream("demos" + fileCount + ".csv");
byteArrayOutputStream = new ByteArrayOutputStream();
byteArrayOutputStream.write(csvOutput);
byteArrayOutputStream.writeTo(outputStream);
}
public static class Orders {
private String orderNumber;
private String productName;
public String getOrderNumber() {
return orderNumber;
}
public void setOrderNumber(String orderNumber) {
this.orderNumber = orderNumber;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
}

Error while uploading huge base64 file to S3 Bucket

I am trying to upload a huge video file to the s3 bucket.
I am getting the data from the client-side in base64 format which I am sending to the S3client to upload to my bucket as shown below:-
public class UploadFileService {
private static final String BUCKET_NAME = "data";
private static final Regions REGION = Regions.US_EAST_2;
LoggerUtils loggerUtils = new LoggerUtils ();
public String uploadFile(String fileData, String fileName, String contentType, String extension){
try {
loggerUtils.log ("File Data" , fileData);
byte[] bI = org.apache.commons.codec.binary.Base64.decodeBase64 ((fileData.substring (fileData.indexOf (",") + 1)).getBytes ());
InputStream fis = new ByteArrayInputStream (bI);
AmazonS3 s3 = new AmazonS3Client ();
Region usWest02 = Region.getRegion (REGION);
s3.setRegion (usWest02);
ObjectMetadata metadata = new ObjectMetadata ();
metadata.setContentLength (bI.length);
metadata.setContentType ("video/mp4");
//metadata.setContentType (contentType + "/" + extension.substring (1));
metadata.setCacheControl ("public, max-age=0");
s3.putObject (BUCKET_NAME, fileName, fis, metadata);
s3.setObjectAcl (BUCKET_NAME, fileName, CannedAccessControlList.PublicRead);
URL s3Url = s3.getUrl(BUCKET_NAME, fileName);
return s3Url.toExternalForm();
}
catch (Exception exception){
loggerUtils.log (exception.toString ());
throw exception;
}
}
public static void main(String[] args) {
String fileName = "abc1.mp4";
String fileData = "hkbk";
new UploadFileService ().uploadFile (fileData, fileName, null, null);
}
}
But if the fileData is usage (base64 of a 2MB video) then I am getting the below error:-
Error:(46, 27) java: constant string too long

Itext sign pdf by string signature in base 64 from client

I am trying to sign a pdf document with a signature that comes from the entire client in format base 64.
the service makes a request to calculate the hash from the document
I take the content from the pdf of the document, calculate the hash from it according to the algorithm.
service takes the received hash and signs it, sends the received signature along with the bytes of the document to be signed
I get a string in base 64 and pdf bytes to be signed
Is it possiple case? I give a code example
public byte[] insertSignature(byte[] document, String signature) {
try (InputStream inputStream = new ByteArrayInputStream(document);
ByteArrayOutputStream os = new ByteArrayOutputStream();
ByteArrayOutputStream result = new ByteArrayOutputStream()) {
byte[] decodeSignature = Base64.decodeBase64(signature);
CAdESSignature cades = new CAdESSignature(decodeSignature, null, null);
var certificate = cades.getCAdESSignerInfo(0).getSignerCertificate();
var subject = new Subject(certificate.getSubjectX500Principal().getEncoded());
List<String> names = getSignaturesFields(document);
String sigFieldName = String.format("Signature %s", names.size() + 1);
PdfName filter = PdfName.Adobe_PPKLite;
PdfName subFilter = PdfName.ETSI_CAdES_DETACHED;
int estimatedSize = 8192;
PdfReader reader = new PdfReader(inputStream);
StampingProperties stampingProperties = new StampingProperties();
if (names.size() > 1) {
stampingProperties.useAppendMode();
}
PdfSigner signer = new PdfSigner(reader, os, stampingProperties);
signer.setCertificationLevel(PdfSigner.CERTIFIED_NO_CHANGES_ALLOWED);
PdfSignatureAppearance appearance = signer.getSignatureAppearance();
appearance
.setContact(subject.email().orElse(""))
.setSignatureCreator(subject.organizationName().orElse(""))
.setLocation(subject.country())
.setReuseAppearance(false)
.setPageNumber(1);
signer.setFieldName(sigFieldName);
ContainerForPrepareSignedDocument external = new ContainerForPrepareSignedDocument(filter, subFilter);
signer.signExternalContainer(external, estimatedSize);
byte[] preSignedBytes = os.toByteArray();
ContainerReadyToSignedDocument extSigContainer = new ContainerReadyToSignedDocument(decodeSignature);
PdfDocument docToSign = new PdfDocument(new PdfReader(new ByteArrayInputStream(preSignedBytes)));
PdfSigner.signDeferred(docToSign, sigFieldName, result, extSigContainer);
docToSign.close();
return result.toByteArray();
}
catch (IOException e) {
throw new InternalException("IO exception by insert signature to document:", e);
}
catch (GeneralSecurityException e) {
throw new InternalException("General security by insert signature to document:", e);
}
catch (CAdESException e) {
throw new InternalException("CAdESException by insert signature to document:", e);
}
}
private List<String> getSignaturesFields(byte[] document)
throws IOException {
try (InputStream inputStream = new ByteArrayInputStream(document);
PdfReader reader = new PdfReader(inputStream);
PdfDocument pdfDocument = new PdfDocument(reader)) {
SignatureUtil signUtil = new SignatureUtil(pdfDocument);
return signUtil.getSignatureNames();
}
}
static class ContainerForPrepareSignedDocument implements IExternalSignatureContainer {
private final PdfName filter;
private final PdfName subFilter;
public ContainerForPrepareSignedDocument(PdfName filter,
PdfName subFilter) {
this.filter = filter;
this.subFilter = subFilter;
}
public byte[] sign(InputStream docBytes) {
return new byte[0];
}
public void modifySigningDictionary(PdfDictionary signDic) {
signDic.put(PdfName.Filter, filter);
signDic.put(PdfName.SubFilter, subFilter);
}
}
static class ContainerReadyToSignedDocument implements IExternalSignatureContainer {
private byte[] cmsSignatureContents;
public ContainerReadyToSignedDocument(byte[] cmsSignatureContents) {
this.cmsSignatureContents = cmsSignatureContents;
}
public byte[] sign(InputStream docBytes) {
return cmsSignatureContents;
}
public void modifySigningDictionary(PdfDictionary signDic) {
}
}

I want to write the ouput of displayDirectoryContents to a excel sheet

I want to write the output of the displayDirectoryContents to a excel sheet
I have tried using the Apache POI method I want to get the output to a excel sheet
Folder and filename in one column and
the name of the files in another column
import statements
public class Excel {
private static String dest = "C:\\Users\\mahselva\\testexcel.xls";
private static HSSFWorkbook myWorkBook = new HSSFWorkbook();
private static HSSFSheet mySheet = myWorkBook.createSheet();
public static void excelLog(String filename, String message, int rowNum)
{
HSSFRow myRow = null;
HSSFCell myCell = null;
String excelData[][] = new String[1][2];
excelData[0][0] = filename;
excelData[0][1] = message;
myRow = mySheet.createRow(rowNum);
for (int cellNum = 0; cellNum < 2; cellNum++) {
myCell = myRow.createCell(cellNum);
myCell.setCellValue(excelData[0][cellNum]);
}
try {
FileOutputStream out = new FileOutputStream(dest);
myWorkBook.write(out);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
File currentDir = new File("C:\\OracleATS\\openScript"); // current
directory
displayDirectoryContents(currentDir);
}
public static void displayDirectoryContents(File dir) {
try {
int i = 0;
File[] files = dir.listFiles();
for (File file : files) {
if (file.isDirectory()) {
Path path = Paths.get(file.getCanonicalPath());
//System.out.println("Folder"
+path.getFileName().toString());
excelLog("Folder",path.getFileName().toString(),i);
i++;
displayDirectoryContents(file);
} else {
Path path = Paths.get(file.getCanonicalPath());
//System.out.println(path.getFileName().toString());
excelLog("File",path.getFileName().toString(),i);
i++;
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
I want two columns in an excel sheet with column 1 containing File or
Folder and column 2 containing the name of the file/folder
eg
File books.xml
Folder Script
Thus i want to write the output to the excel sheet
i am using the function excel log to write to the output screen

I use this to write to an excel - however I make it .csv format, not xls. Therefore this might not be what you need, but it's still partially useful as it's writing in a file that can be opened by excel efortlessly.
public static void printAtFile(String filename, String header, String content[])
{
filename+=".csv";
System.out.println("Start creating file "+filename);
PrintWriter writer = null;
try {
writer = new PrintWriter(filename);
writer.println(header);
for(String u:content)
writer.println(u);
writer.close();
} catch (Exception ex) {
System.out.println("Error while writing at file "+filename);
}
}

Exporting automated value to excel file in java

I am using selenium webdriver in eclipse with Java for a project at work. I am in need of exporting a value to an excel file. I am able to write to an excel file but am unable to export the specific value to the excel file.
Here is the automation process for getting the value:
public void AbbeyNational (String AbbeyNationalURL, String AN_AccCookiesButton, String AN_MortgageTabButton, String AN_ExistingCustomerButton, String AN_FollowRateButton, String AN_SVRButton, String AN_RateFld)throws InterruptedException {
driver.get(AbbeyNationalURL);
driver.findElement(By.xpath(AN_AccCookiesButton)).click();
driver.findElement(By.linkText(AN_MortgageTabButton)).click();
driver.findElement(By.xpath(AN_ExistingCustomerButton)).click();
driver.findElement(By.xpath(AN_FollowRateButton)).click();
driver.findElement(By.xpath(AN_SVRButton)).click();
String a = driver.findElement(By.cssSelector(AN_RateFld)).getText();
String AN_Rate = a.substring(54,58);
System.out.println(AN_Rate);
}
The 'AN_Rate' variable holds the value after automation.
The value prints to the console but I need the value to be exported to the excel file with the use of automation. Can anyone help me with this?
Additionally, here is my code for writing to an excel file:
public void writeToExcel(String AN_Rate) throws IOException{
File file = new File(filePath+"\\"+fileName);
XSSFWorkbook IRWorkbook = new XSSFWorkbook();
XSSFSheet Sheet0 = IRWorkbook.createSheet();
Sheet0.createRow(0).createCell(0).setCellValue(AN_Rate);
try {
FileOutputStream fos = new FileOutputStream(file);
IRWorkbook.write(fos);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

you can use this code for large set of data :
public class ExcelWriter {
// LinkedHashMap to maintain the insertion order
public static Map<String, String> dataMap = new LinkedHashMap<>();
public static String filePath = "D:\\ECLIPSE-WORKSPACE\\playground\\src\\main\\resources";
public static String fileName = "demo-data";
public static void main(String[] args) throws IOException {
String AN_Rate = "Data-1";
String BN_Rate = "Data-2";
String CN_Rate = "Data-3";
dataMap.put("AN_Rate", AN_Rate);
dataMap.put("BN_Rate", BN_Rate);
dataMap.put("CN_Rate", CN_Rate);
writeToExcel(dataMap, filePath, fileName);
}
public static void writeToExcel(Map<String, String> dataMap, String filePath, String fileName) throws IOException {
File file = new File(filePath + "\\" + fileName + ".xlsx");
if (file.exists()) {
file.delete();
}
file.createNewFile();
XSSFWorkbook IRWorkbook = new XSSFWorkbook();
XSSFSheet sheet = IRWorkbook.createSheet();
List<String> headers = dataMap.keySet().stream().collect(Collectors.toList()); // all key values in a list
List<String> data = new ArrayList<>(dataMap.values()); // all data in a list
setHeadersAndFillData(sheet, headers, data); // filling excel sheet with headers and corresponding data
try {
FileOutputStream fos = new FileOutputStream(file);
IRWorkbook.write(fos);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public static void setHeadersAndFillData(XSSFSheet sheet, List<String> headers, List<String> data) {
int headersSize = headers.size();
int dataSize = headers.size();
Row headerRow = sheet.createRow(0);
Row dataRow = sheet.createRow(1);
setCells(headers, headersSize, headerRow);
setCells(data, dataSize, dataRow);
}
private static void setCells(List<String> cellData, int headersSize, Row row) {
for (int rn = 0; rn < headersSize; rn++) {
row.createCell(rn).setCellValue(cellData.get(rn));
}
}
}

Just edit your method writeToExcel with :
Replace :File file = new File(filePath+"\\"+fileName);
with added file extention
File file = new File(filePath+"\\"+fileName + ".xlsx");
and than the value will be exported to excel file.
And if there is large set of data than you should store all values in a static map and than export all values to excel at once.