We Keep Coding

Add data to specific record in CSV file

I have a record in a CSV file and i am trying to add some extra info (a name) to the same specific record with the following code but it does not work. There is no error shown but the info i am trying to add just does not appear. What am i missing ?
public class AddName {
public static void main(String[] args) {
String filepath="Zoo.csv";
String editTerm="Fish";
String addedName="Ron";
addToRecord(filepath,editTerm,addedName);
}
public static void addToRecord(String filepath,String editTerm,String addedName){
String animal= "";
try{
FileWriter fw=new FileWriter(filepath,true);
BufferedWriter bw=new BufferedWriter(fw);
PrintWriter pw=new PrintWriter(bw);
if (animal.equals(editTerm)){
pw.println(editTerm+","+addedName);
pw.flush();
pw.close();
}
System.out.println("Your Record was saved");
}
catch(Exception e){
System.out.println("Your Record was not saved");
e.printStackTrace();
}
}

You could consider using a CSV library to help you out with parsing CSVs because it is more complicated than it looks, especially when it comes down to quoting.
Here's a quick example using OpenCSV that clones the original CSV file and adds "Ron" as necessary:
public class Csv1 {
public static void main(String[] args) throws IOException, CsvValidationException {
addToRecord("animal.csv", "animal-new.csv", "fish", "Ron");
}
public static void addToRecord(String filepathIn, String filepathOut, String editTerm, String addedName)
throws IOException, CsvValidationException {
try (CSVReader reader = new CSVReader(new FileReader(filepathIn))) {
try (CSVWriter writer = new CSVWriter(new FileWriter(filepathOut))) {
String[] values;
while ((values = reader.readNext()) != null) {
if (values.length > 2 && values[0].equals(editTerm)) {
values[1] = addedName;
}
writer.writeNext(values);
}
}
}
}
}
Given the file:
type,name,age
fish,,10
cat,,12
lion,tony,10
will produce:
"type","name","age"
"fish","Ron","10"
"cat","","12"
"lion","tony","10"
(You can look for answers about outputting quotes in the resulting CSV)

Here the requirement is to add an extra column if the animal name matches. It's equivalent to changing a particular line in a file. Here's a simple approach to achieve the same, (Without using any extra libraries),
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
public class EditLineInFile {
public static void main(String[] args) {
String animal = "Fish";
Path path = Paths.get("C:\\Zoo.csv");
try {
List<String> allLines = Files.readAllLines(path);
int counter = 0;
for (String line : allLines) {
if (line.equals(animal)) {
line += ",Ron";
allLines.set(counter, line);
}
counter++;
}
Files.write(path, allLines);
} catch (IOException e) {
e.printStackTrace();
}
}
}

You may use this code to replace the file content "Fish" to "Fish, Ron"
public static void addToRecord(String filepath, String editTerm, String addedName) {
try (Stream<String> input = Files.lines(Paths.get(filepath));
PrintWriter output = new PrintWriter("Output.csv", "UTF-8"))
{
input.map(s -> s.replaceAll(editTerm, editTerm + "," + addedName))
.forEachOrdered(output::println);
} catch (IOException e) {
e.printStackTrace();
}
}

Permission denied when trying to write with FileWriter/BufferedWriter in java.

im really struggling one this one. Basically im working with a couple of my classmates to a project where we have to deliver a space wars remake and we implemented a single player mode where you can actually get scores. problem is i can read my file but cannot write on it. ive tryed with all the system i could find online but didn't manage to get the error solved. here is the code of the class that manages the highscore system. i even tryed creating the file with code and tryed deleting it and recreating an empty one. the file is in the home directory of the project right now. the metods readFile and getHighscores work but the check one always gets stuck in the writing part.
the error i get is " Il privilegio richiesto non appartiene al client
[Ljava.lang.StackTraceElement;#6eb60ef7"
which translates in "The requested privilege does not belong to the client"
Keep in mind it's all in a git repository where i should have all the permissions but it's basically the only idea left in my mind.
package controller;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
/**
*the creation of the HighscoreManager class.
*/
public class HighscoreManager {
private static final int LAST_HIGHSCORE_INDEX = 9;
private static final String FILE_NAME = "/Highscores.txt";
private ArrayList<Integer> highscores = new ArrayList<Integer>();
/**
* reads the file and loads the highscore list.
*/
private void readFile() {
InputStream is = null;
InputStreamReader isr = null;
BufferedReader br = null;
String s;
highscores.clear();
try {
is = this.getClass().getResourceAsStream(FILE_NAME);
isr = new InputStreamReader(is);
br = new BufferedReader(isr);
while ((s = br.readLine()) != null) {
highscores.add(Integer.parseInt(s));
}
if(br!=null && isr !=null && is!= null) {
br.close();
isr.close();
is.close();
}
} catch (Exception e) {
System.out.println(e.getMessage());
}
}
/**
* checks if the passed score is an actual highscores.
* #param score
*/
public void checkHighscores(final int score) {
readFile();
File file = new File(FILE_NAME);
boolean newHighscoreFound = false;
for (int i = 0; i < highscores.size(); i++) {
if (score > highscores.get(i)) {
newHighscoreFound = true;
break;
}
}
if (newHighscoreFound) {
highscores.add(LAST_HIGHSCORE_INDEX, score);
Collections.sort(highscores);
Collections.reverse(highscores);
for (int i : highscores) {
System.out.println(i);
}
if(!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
FileWriter fw = null;
BufferedWriter bw = null;
try {
fw = new FileWriter(file);
bw = new BufferedWriter(fw);
for(int i : highscores) {
bw.write(i);
}
} catch(IOException e) {
System.out.println(e.getStackTrace());
} finally {
if(fw != null && bw != null) {
try {
fw.close();
bw.close();
} catch (IOException e) {
System.out.println(e.getStackTrace());
}
}
}
}
}
/**
* returns an array list of strings containing all the current highscores.
* #return toBeReturned
*/
public ArrayList<String> getHighscores() {
ArrayList<String> toBeReturned = new ArrayList<>();
try {
highscores.clear();
readFile();
for (int i : highscores) {
toBeReturned.add(String.valueOf(i));
}
} catch (Exception e) {
System.out.println(e.getMessage());
} finally {
System.out.println("There you have your highscores.");
}
return toBeReturned;
}
}

You don't need to access the Class object to load a file (or indeed the associated ClassLoader). Just use normal Java IO.
To read your set of high scores:
highScores = Files.lines(Paths.get(FILE_NAME))
.map(Integer::parseInt)
.collect(Collectors.toList());
To write a new set of high scores:
Files.write(Paths.get(FILE_NAME), highScores.stream()
.map(String::valueOf)
.collect(Collectors.toList()));
(Also, why is this tagged with "git"?)

Start and stop postgreSQL service through java code

I have one requirement where I need to start and stop postgreSQL service through java code. I have written below code but I am getting below error:
System error 5 has occurred.
Access is denied.
System error 5 has occurred.
Access is denied.
Below is my code:
package frontend.guifx.pginstallation;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import common.core.Logger;
import frontend.guifx.util.ConstPG;
public class StartAndStopPostgres {
public static String version = "9.5";
public static void main(String[] args){
try {
System.out.println("Execution starts");
copyPostgreSqlConfFileAndRestartPg();
System.out.println("Execution finished");
} catch (IOException | InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private static void copyPostgreSqlConfFileAndRestartPg() throws IOException, InterruptedException {
// TODO Auto-generated method stub
Path path = Paths.get("data/PGLogs");
//if directory exists?
if (!Files.exists(path)) {
try {
Files.createDirectories(path);
} catch (IOException e) {
//fail to create directory
e.printStackTrace();
}
}
Logger.print(StartAndStopPostgres.class, new String[] { "Copying postgresql.conf file ........" });
Path source = Paths.get("data/postgresql.windows.conf");
String copyConfFileTo = getInstallationPath(version);
copyConfFileTo = copyConfFileTo.substring(0, copyConfFileTo.lastIndexOf("\\"));
Path outputDirectoryPath = Paths.get(copyConfFileTo+File.separator+"data");
Files.copy(source, outputDirectoryPath.resolve(outputDirectoryPath.getFileSystem().getPath("postgresql.conf")), StandardCopyOption.REPLACE_EXISTING);
Logger.print(StartAndStopPostgres.class, new String[] { "Tunning datbase starts........" });
Runtime rt = Runtime.getRuntime();
final File file = new File(System.getProperty("java.io.tmpdir") + File.separator + ConstPG.CREATE_RESTART_PG_BAT_FILE);
PrintWriter writer = new PrintWriter(file, "UTF-8");
writer.println("net stop postgresql-x64-"+version);
writer.println("net start postgresql-x64-"+version);
writer.close();
String executeSqlCommand = file.getAbsolutePath();
Process process = rt.exec(executeSqlCommand);
/*final List<String> commands = new ArrayList<String>();
commands.add("cmd.exe");
commands.add("/C");
commands.add("net stop postgresql-x64-9.5");
commands.add("net start postgresql-x64-9.5");
ProcessBuilder b = new ProcessBuilder(commands);
Process process = b.start();*/
//public static final String PG_RESTART_PG_LOG_FILE = PG_LOGS+"/pgRestartProcess.log";
File createPgRestartProcessFile = new File(ConstPG.PG_RESTART_PG_LOG_FILE);
redirectProcessExecutionOutput(process, createPgRestartProcessFile);
int exitVal = process.waitFor();
Logger.print(StartAndStopPostgres.class, new String[] { "EXIT VALUE after tunning the PostgreSql database :::::::::::::::::::::" + exitVal + " Logs written to file at: " + createPgRestartProcessFile.getAbsolutePath() });
}
public static String getInstallationPath( String version) {
//public static final String PROGRAMME_FILES = "C:\\Program Files\\";
// public static final String PROGRAMME_FILES_X86 = "C:\\Program Files (x86)\\";
// public static final String POSTGRESQL = "PostgreSQL";
// public static final String PSQL_PATH = "\\bin\\psql.exe";
//Const values used below are as above
String psql = findFile(ConstPG.PROGRAMME_FILES, ConstPG.POSTGRESQL + "\\" + version + ConstPG.PSQL_PATH);
if (psql == null) {
psql = findFile(ConstPG.PROGRAMME_FILES_X86, ConstPG.POSTGRESQL + "\\" + version + ConstPG.PSQL_PATH);
}
if(psql != null){
psql = psql.substring(0, psql.lastIndexOf("\\"));
}
return psql;
}
public static String findFile(String directoryName, String fileName) {
File directory = new File(directoryName);
// get all the files from a directory
File[] fList = directory.listFiles();
String absolutePath;
if (fList != null) {
for (File file : fList) {
if (file.isFile()) {
absolutePath = file.getAbsolutePath();
if (absolutePath.contains(fileName))
return (absolutePath);
} else if (file.isDirectory()) {
absolutePath = findFile(file.getAbsolutePath(), fileName);
if (absolutePath != null)
return (absolutePath);
}
}
}
return (null);
}
private static void redirectProcessExecutionOutput(Process process, File processFile) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
String line = null;
FileWriter fw = new FileWriter(processFile.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
while ((line = reader.readLine()) != null) {
Logger.print(StartAndStopPostgres.class, new String[] { line });
bw.write(line);
bw.newLine();
}
bw.close();
}
}
If I start my eclipse as an Administrator then this works fine. Also if I run start and stop commands on command prompt (which is opened as an Administrator i.e. right click on command prompt icon and click 'run as Administrator') then they execute successfully. But if I run the commands on normal command prompt (which is not opened as a administrator) then I get the same error there as well.
Please advise if there is any solution or any approach to solve this problem.

In java there is a option to run windows cmd as administrator
replace your code "commands.add("cmd.exe");" with below code and try
commands.add("runas /profile /user:ADMINUSERNAME \"cmd.exe");

How can i remove a word/line and replace it with a new one in a txt file (Java)?

For example we have a .txt file:
Name smth
Year 2012
Copies 1
And I want to replace it with that:
Name smth
Year 2012
Copies 0
Using java.io.*.

Here is the code that does that. Let me know if you have any question.
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.LinkedHashMap;
import java.util.Map;
public class Test2 {
Map<String, String> someDataStructure = new LinkedHashMap<String, String>();
File fileDir = new File("c:\\temp\\test.txt");
public static void main(String[] args) {
Test2 test = new Test2();
try {
test.readFileIntoADataStructure();
test.writeFileFromADataStructure();
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
private void readFileIntoADataStructure() throws IOException {
BufferedReader in = new BufferedReader(new InputStreamReader(
new FileInputStream(fileDir)));
String line;
while ((line = in.readLine()) != null) {
if (line != null && !line.trim().isEmpty()) {
String[] keyValue = line.split(" ");
// Do you own index and null checks here this is just a sample
someDataStructure.put(keyValue[0], keyValue[1]);
}
}
in.close();
}
private void writeFileFromADataStructure() throws IOException {
Writer out = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(fileDir)));
for (String key : someDataStructure.keySet()) {
// Apply whatever business logic you want to apply here
myBusinessMethod(key);
out.write(key + " " + someDataStructure.get(key) + "\n");
out.append("\r\n");
out.append("\r\n");
}
out.flush();
out.close();
}
private String myBusinessMethod(String data) {
if (data.equalsIgnoreCase("Copies")) {
someDataStructure.put(data, "0");
}
return data;
}
}

Read your original text file line by line and separate them into string tokens delimited by spaces for output, then when the part you want replaced is found (as a string), replace the output to what you want it to be. Adding the false flag to the filewrite object ("filename.txt", false) will overwrite and not append to the file allowing you to replace the contents of the file.

this is the code to do that
try {
String sCurrentLine;
BufferedReader br = new BufferedReader(new FileReader("yourFolder/theinputfile.txt"));
BufferedWriter bw = new BufferedWriter(new FileWriter("yourFolder/theinputfile.txt" , false));
while ((sCurrentLine = br.readLine()) != null) {
if(sCurrentLine.indexOf("Copies")>=0){
bw.write("Copies 0")
}
System.out.println(sCurrentLine);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
br.close()bw.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
hopefully that help

Read from file inside Eclipse Project

I want to make an application that splits a big text file inside inputfolder into several small XML files to be put inside outputfolder.
This is project outline:
The following code works fine when it comes to getting a file from an outside folder, but when I modified it to read from a folder inside the project, it gave me this error:
Exception in thread "main" java.lang.NullPointerException
at com.zakaria.cut.XmlCutter.cut(XmlCutter.java:45)
at com.zakaria.cut.Main.main(Main.java:8)
[XmlCutter.java]
package com.zakaria.cut;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.text.MessageFormat;
import java.util.logging.ConsoleHandler;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.Logger;
public class XmlCutter {
private static final String OUTPUT_FILE_NAME = "/file";
//private static String USER_HOME = System.getProperty("user.home");
private static final String INPUT_FOLDER = "../inputfolder";
private static String OUTPUT_FOLDER = "../outputfolder";
private static Logger LOG = Logger.getLogger("XmlCutter");
private static long COUNTER = 0;
public XmlCutter() {
super();
// TODO Auto-generated constructor stub
}
public void cut() {
Handler h = new ConsoleHandler();
h.setLevel(Level.FINE);
LOG.addHandler(h);
LOG.setLevel(Level.FINE);
File inputDir = new File(INPUT_FOLDER);
File[] filesInInputDir = inputDir.listFiles();
for (File f : filesInInputDir) {
if ((f.getName()).endsWith(".txt")) {
LOG.fine((MessageFormat.format(
"Found a text file {0}. Processing docs...",
f.getName())));
processFile(f);
}
}
}
private static void processFile(File f) {
StringBuilder out = new StringBuilder();
char prev = '#';
try {
BufferedReader br = new BufferedReader(new InputStreamReader(
new FileInputStream(f), "UTF8"));
char[] buf = new char[1];
while (br.read(buf) >= 0) {
out.append(buf[0]);
if (prev == '<' && buf[0] == '?') {
LOG.finest((MessageFormat.format(
"Start of XML PI Found: {0}{1}", prev, buf[0])));
if (out.length() > 2) {
flushToFile(out.substring(0, out.length() - 2));
}
out.setLength(2);
}
prev = buf[0];
}
LOG.finest("Writing final file");
flushToFile(out.toString());
br.close();
} catch (IOException e) {
LOG.fine(e.getMessage());
}
LOG.fine(MessageFormat.format("Generated {0} XML Documents", COUNTER));
}
private static void flushToFile(String s) {
File f = new File(OUTPUT_FOLDER + OUTPUT_FILE_NAME + (++COUNTER)
+ ".xml");
LOG.finest(MessageFormat.format("Writing file: {0}", f.getName()));
try {
FileOutputStream fos = new FileOutputStream(f);
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF8");
osw.write(s);
osw.flush();
} catch (IOException e) {
LOG.fine(e.getMessage());
}
}
}
[Main.java]
package com.zakaria.cut;
public class Main {
public static void main(String[] args) {
XmlCutter cutter = new XmlCutter();
cutter.cut();
}
}
The problem, I guess, is definitely here:
private static final String INPUT_FOLDER = "../inputfolder";
private static String OUTPUT_FOLDER = "../outputfolder";
How can I fix it?

Do you know what folder the program is executing from? My guess is the relative links are pointing to the wrong spot? Have you tried hard coding the paths and see if they work? If they do you might have to look at the your execution folder and then change the relative paths accordingly?