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how to copy only a part of .CSV based on first column elements with java

copy part like this(from date to date) I am trying to copy only a part of .CSV file based on the first column (Start Date and Time) data looks like (2019-01-28 10:22:00 AM) but the user have to put it like this (2019/01/28 10:22:00)
this is for windows, java opencsv , this is what I found but dont do what I need exaclty :
like this:
int startLine = get value1 from column csv ;
int endLine = get value2 from column csv;
public static void showLines(String fileName, int startLine, int endLine) throws IOException {
String line = null;
int currentLineNo = 1;
// int startLine = 20056;//40930;
// int currentLineNo = 0;
File currentDirectory = new File(new File(".").getAbsolutePath());
String fromPath = currentDirectory.getCanonicalPath() + "\\Target\\part.csv";
PrintWriter pw = null;
pw = new PrintWriter(new FileOutputStream(fromPath), true);
//pw.close();
BufferedReader in = null;
try {
in = new BufferedReader (new FileReader(fileName));
//read to startLine
while(currentLineNo<startLine) {
if (in.readLine()==null) {
// oops, early end of file
throw new IOException("File too small");
}
currentLineNo++;
}
//read until endLine
while(currentLineNo<=endLine) {
line = in.readLine();
if (line==null) {
// here, we'll forgive a short file
// note finally still cleans up
return;
}
System.out.println(line);
currentLineNo++;
pw.println(line);
}
} catch (IOException ex) {
System.out.println("Problem reading file.\n" + ex.getMessage());
}finally {
try { if (in!=null) in.close();
pw.close();
} catch(IOException ignore) {}
}
}
public static void main(String[] args) throws FileNotFoundException {
int startLine = 17 ;
int endLine = 2222;
File currentDirectory = new File(new File(".").getAbsolutePath());
try {
showLines(currentDirectory.getCanonicalPath() + "\\Sources\\concat.csv", startLine, endLine);
} catch (IOException e) {
e.printStackTrace();
}
// pw.println();
}

Common CSV format uses a comma as a delimiter, with quotations used to escape any column entry that uses them within the data. Assuming that your column one data is consistent with the format you posted, and that I wouldn't have to bother with quotations marks therefor, you could read the columns as:
public static void main(String[] args) {
//This is the path to the file you are writing to
String targetPath = "";
//This is the path to the file you are reading from
String inputFilePath = "";
String line = null;
ArrayList<String> lines = new ArrayList<String>();
boolean add = false;
String startLine = "2019/01/28 10:22:00";
String endLine = "2019/01/28 10:30:00";
String addFlagSplit[] = startLine.replace("/", "-").split(" ");
String addFlag = addFlagSplit[0] + " " + addFlagSplit[1];
String endFlagSplit[] = endLine.replace("/", "-").split(" ");
String endFlag = endFlagSplit[0] + " " + endFlagSplit[1];
try(PrintWriter pw = new PrintWriter(new FileOutputStream(targetPath), true)){
try (BufferedReader input = new BufferedReader(new FileReader(inputFilePath))){
while((line = input.readLine()) != null) {
String date = line.split(",")[0];
if(date.contains(addFlag)) {
add = true;
}else if(date.contains(endFlag)) {
break;
}
if(add) {
lines.add(line);
}
}
}
for(String currentLine : lines) {
pw.append(currentLine + "\n");
}
}catch(FileNotFoundException e) {
e.printStackTrace();
}catch(IOException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws IOException {
File currentDirectory = new File(new File(".").getAbsolutePath());
String targetPath = currentDirectory.getCanonicalPath() + "\\Target\\part.csv";
String inputFilePath = currentDirectory.getCanonicalPath() + "\\Sources\\concat.csv";
String line = null;
ArrayList<String> lines = new ArrayList<String>();
boolean add = false;
String startLine = "2019/01/28 10:22:00";
String endLine = "2019/04/06 10:30:00";
try(PrintWriter pw = new PrintWriter(new FileOutputStream(targetPath), true)){
try (BufferedReader input = new BufferedReader(new FileReader(inputFilePath))){
while((line = input.readLine()) != null) {
String date = line.split(",")[0];
if(date.contains(startLine)) {
add = true;
}else if(date.contains(endLine)) {
break;
}
if(add) {
lines.add(line);
}
}
}
for(String currentLine : lines) {
pw.append(currentLine + "\n");
}
}catch(FileNotFoundException e) {
e.printStackTrace();
}catch(IOException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}

Java - Trying to output to a file where if the user's login is there only replace the balance

My program is basically a user's name, and balance, this is stored in a file, when the user updates their profile, I want their balance to update too, but not their name, as they already have it in the file.
The name and balance are split with a comma. In the file it is displayed like this:
Stacey,0.02
(The name is actually a randomly generated number+letter string, but I thought I'd keep it simple here.)
When I try to write to the file with this code, it doesn't write anything.
Code:
btnSaveUserid.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String text = txtUserid.getText().toString();
String balance = beedcoin1Balance.getText().toString();
File file = new File("d:/users/joel/desktop/code/usersid.txt");
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader("d:/users/joel/desktop/code/usersid.txt"));
List<String> terms = new ArrayList<String>();
List<String> ttlBalance = new ArrayList<String>();
while ((sCurrentLine = br.readLine()) != null) {
String[] ar = sCurrentLine.split(",");
String userid = ar[0];
terms.add(userid);
System.out.println(terms);
}
if(terms.contains(text)) {
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("d:/users/joel/desktop/code/usersid.txt")));
Scanner scanner = new Scanner(file);
while(scanner.hasNextLine());
String line = scanner.nextLine();
String[] ar = line.split(",");
String userid = ar[0];
String bdcv1val = ar[1];
int lineNum = 0;
lineNum++;
if(line.equals(userid)) {
Path path = Paths.get("d:/users/joel/desktop/code/usersid.txt");
Charset charset = StandardCharsets.UTF_8;
String content = new String(Files.readAllBytes(path), charset);
content = content.replace(txtUserid.toString(), txtUserid.toString());
Files.write(path, content.getBytes(charset));
out.println(text + "," + balance);
System.out.println("Successfully printed to usersid.txt");
}
}
else {
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("d:/users/joel/desktop/code/usersid.txt")));
out.println(text + "," + balance);
System.out.println("Successfully printed to usersid.txt");
}
} catch (IOException el) {
el.printStackTrace();
} finally {
try {
if(br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
It all takes place in a button's action listener, and this code outputs the "Successfully printed to file" but doesn't actually print it to the file. I'm honestly perplexed, any help would be greatly appreciated.

Read and Write CSV File using Java

I have a CSV log file and it contains many rows like this:
2016-06-21 12:00:00,000 : helloworld: header1=2;header2=6;header=0
I want to write them to a new CSV file.
public void readLogFile() throws Exception
{
String currentLine = "";
String nextLine = "";
BufferedReader reader = new BufferedReader(new FileReader(file(false)));
while ((currentLine = reader.readLine()) != null)
{
if (currentLine.contains("2016") == true)
{
nextLine = reader.readLine();
if (nextLine.contains("helloworld") == true)
{
currentLine = currentLine.substring(0, 23);
nextLine = nextLine.substring(22, nextLine.length());
String nextBlock = replaceAll(nextLine);
System.out.println(currentLine + " : helloworld: " + nextBlock);
String[] data = nextBlock.split(";");
for (int i = 0, max = data.length; i < max; i++)
{
String[] d = data[i].split("=");
map.put(d[0], d[1]);
}
}
}
}
reader.close();
}
This is my method to write the content:
public void writeContentToCsv() throws Exception
{
FileWriter writer = new FileWriter(".../file_new.csv");
for (Map.Entry<String, String> entry : map.entrySet())
{
writer.append(entry.getKey()).append(";").append(entry.getValue()).append(System.getProperty("line.separator"));
}
writer.close();
}
This is the output I want to have:
header1; header2; header3
2;6;0
1;5;1
5;8;8
...
Currently, the CSV file looks like this (only showing one dataset):
header1;4
header2;0
header3;0
Can anyone help me fix the code?

Create a class to store the header values, and store it in the list.
Iterate over the list to save the results.
The currently used map can only store 2 values (which it is storing the header value (name its corresponding value)
map.put(d[0], d[1]);
here d[0] will be header1 and d[1] will be 4 (but we want only 4 from here)
class Headervalues {
String[] header = new String[3];
}
public void readLogFile() throws Exception
{
List<HeaderValues> list = new ArrayList<>();
String currentLine = "";
BufferedReader reader = new BufferedReader(new FileReader(file(false)));
while ((currentLine = reader.readLine()) != null)
{
if (currentLine.contains("2016") && currentLine.contains("helloworld"))
{
String nextBlock = replaceAll(currentLine.substring(22, currentLine.length());
String[] data = nextBlock.split(";");
HeaderValues headerValues = new HeaderValues();
//Assuming data.length will always be 3.
for (int i = 0, max = data.length; i < max; i++)
{
String[] d = data[i].split("=");
//Assuming split will always have size 2
headerValues.header[i] = d[1];
}
list.add(headerValues)
}
}
}
reader.close();
}
public void writeContentToCsv() throws Exception
{
FileWriter writer = new FileWriter(".../file_new.csv");
for (HeaderValues value : headerValues)
{
writer.append(value.header[0]).append(";").append(value.header[1]).append(";").append(value.header[2]);
}
writer.close();
}

For writing to CSV
public void writeCSV() {
// Delimiter used in CSV file
private static final String NEW_LINE_SEPARATOR = "\n";
// CSV file header
private static final Object[] FILE_HEADER = { "Empoyee Name","Empoyee Code", "In Time", "Out Time", "Duration", "Is Working Day" };
String fileName = "fileName.csv");
List<Objects> objects = new ArrayList<Objects>();
FileWriter fileWriter = null;
CSVPrinter csvFilePrinter = null;
// Create the CSVFormat object with "\n" as a record delimiter
CSVFormat csvFileFormat = CSVFormat.DEFAULT.withRecordSeparator(NEW_LINE_SEPARATOR);
try {
fileWriter = new FileWriter(fileName);
csvFilePrinter = new CSVPrinter(fileWriter, csvFileFormat);
csvFilePrinter.printRecord(FILE_HEADER);
// Write a new student object list to the CSV file
for (Object object : objects) {
List<String> record = new ArrayList<String>();
record.add(object.getValue1().toString());
record.add(object.getValue2().toString());
record.add(object.getValue3().toString());
csvFilePrinter.printRecord(record);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
fileWriter.flush();
fileWriter.close();
csvFilePrinter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

Read and write/append CSV file using org.apache.commons.csv.CSVParser.
public void appendCSV(){
String [] records = {};
String csvWrite= "";
Boolean status = false;
try(BufferedReader csvReaders = new BufferedReader(new FileReader("csvfile.csv"));
CSVParser parser = CSVFormat.DEFAULT.withDelimiter(',').withHeader().parse(csvReaders);
) {
for(CSVRecord record : parser) {
status= record.get("Microservice").equalsIgnoreCase(apipath);
int status_code=0;
String httpMethod = record.get("Method");
if(status==true) {
csvWrite = record.get("apiName")+"-"+record.get("Microservice")+"-"+record.get("R_Data")+"-"+record.get("Method")+"-"+record.get("A_Status")+"-"+400+"-"+record.get("A_Response")+"-"+"{}";
records = csvWrite.split("-");
CSVWriter writer = new CSVWriter(new FileWriter(pathTowritecsv,true));
writer.writeNext(records);
writer.close();
}else {
}
}
}
catch (Exception e) {
System.out.println(e);
}
}

Add two csv file to a list in Java

My Java program has a superclass (ProgettoBase) and two underclasses (ProgettoCorpo and ProgettoOre). I must copy two different csv files (progetti_ora.csv and progetti_corpo.csv) to a list but I can't see the elements of the list when I launch the program.
public void readFile () {
List<String> projects = new ArrayList<>();
System.out.println("My list is: " + projects);
//read 1 progetti_ora
String csvFile = "progetti_ora.csv";
BufferedReader br = null;
String line = "";
String cvsSplitBy = ";";
//read 2 progetti_corpo
String csvFileDue = "progetti_corpo.csv";
BufferedReader brDue = null;
String lineDue = "";
String cvsSplitByDue = ";";
//read file 1
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
String[] vote = line.split(cvsSplitBy);
for(String s : vote)
System.out.println("List one: " + s);
for(int x = 0; x <= 2; x++) {
projects.add(vote[x].toString());
}
}
} catch (Exception e) {
System.out.println(e.getMessage());
}
System.out.println("OK1");
//read file 2
try {
brDue = new BufferedReader(new FileReader(csvFileDue));
while ((lineDue = brDue.readLine()) != null) {
String[] voteDue = lineDue.split(cvsSplitByDue);
for(String t : voteDue)
System.out.println("Lista file due: " + t);
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
System.out.println("OK2");
}

Save content of File as String in Java?

I was working a little bit with config files and file reader classes in java.
I always read/wrote in the files with arrays because I was working with objects.
This looked a little bit like this:
public void loadUserData(ArrayList<User> arraylist) {
try {
List<String> lines = Files.readAllLines(path, Charset.defaultCharset());
for(String line : lines) {
String[] userParams = line.split(";");
String name = userParams[0];
String number= userParams[1];
String mail = userParams[2];
arraylist.add(new User(name, number, mail));
}
} catch (IOException e) {
e.printStackTrace();
}
}
This works fine, but how can I save the content of a file as only one single string?
When I read a file, the string I use should be the exact same as the content of the file (without the use of arrays or line splits).
how can I do that?
Edit:
I try to read a SQL-Statement out of a file to use it with JDBC later on. That's why I need the content of the File as a single String

This method will work
public static void readFromFile() throws Exception{
FileReader fIn = new FileReader("D:\\Test.txt");
BufferedReader br = new BufferedReader(fIn);
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
sb.append("\n");
}
String text = sb.toString();
System.out.println(text);
}

I hope this is what you need:
public void loadUserData(ArrayList<User> arraylist) {
StringBuilder sb = new StringBuilder();
try {
List<String> lines = Files.readAllLines(path, Charset.defaultCharset());
for(String line : lines) {
// String[] userParams = line.split(";");
//String name = userParams[0];
//String number= userParams[1];
//String mail = userParams[2];
sb.append(line);
}
String jdbcString = sb.toString();
System.out.println("JDBC statements read from file: " + jdbcString );
} catch (IOException e) {
e.printStackTrace();
}
}
or maybe this:
String content = new Scanner(new File("filename")).useDelimiter("\\Z").next();
System.out.println(content);

Just do that:
final FileChannel fc;
final String theFullStuff;
try (
fc = FileChannel.open(path, StandardOpenOptions.READ);
) {
final ByteBuffer buf = ByteBuffer.allocate(fc.size());
fc.read(buf);
theFullStuff = new String(buf.array(), theCharset);
}
nio for the win! :p

You could always create a Buffered reader e.g.
File anInputFile = new File(/*input path*/);
FileReader aFileReader = new FileReader(anInputFile);
BufferedReader reader = new BufferedReader(aFileReader)
String yourSingleString = "";
String aLine = reader.readLine();
while(aLine != null)
{
singleString += aLine + " ";
aLine = reader.readLine();
}