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Out of bounds error, while reading file then splitting it [closed]

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Closed 1 year ago.
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I've been getting an Array Index Out of Bounds Error.
Basically I have a file where a user name and password is saved lke this: user:password
I'm trying to read the file to check if a new user is already signed in or not. This is in a thread and also using a socket.
private void authentication(String user, String password) {
List<String> nomes = new ArrayList<>();
List<String> pass = new ArrayList<>();
BufferedReader reader;
try {
FileWriter fw = new FileWriter("users.txt", true);
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter out = new PrintWriter(bw);
BufferedReader br = new BufferedReader(new FileReader("users.txt"));
//String line;
String line;
while((line = br.readLine())!=null){
String[] pair = line.split(";");
nomes.add(pair[0]);
pass.add(pair[1]);
}
/*while ((line = br.readLine()) != null) {
String[] info = line.split(":");
System.out.println(line);
System.out.println(info[0]);
System.out.println(info[1]);
}*/
if(nomes.isEmpty()) {
out.println(user + ":" + password);
System.out.println("Novo Utilizador Autenticado.");
System.out.println("Bem Vindo!!");
}else if(nomes.contains(user)) {
bw.newLine();
if(password.equals(pass.get(nomes.indexOf(user)))) {
System.out.println("Utilizador autenticado com sucesso!");
System.out.println("Bem Vindo de Volta!!");
}
}else {
terminate();
}
bw.close();
br.close();
out.close();
} catch (IOException e) {
System.out.println("An error occurred.");
e.printStackTrace();
}
}
The error is happening in the last line on the pair[1]. It has a value but for some reason isn't seeing it.

Your text in the file is like "user:password" and you are trying to split it with ";". So pair[1] won't have any value. You should try split it with ":"

Try to access the values dynamically using index instead of hardcoded 0,1 to avoid index out of bond exception :
while ((line = br.readLine()) != null) {
String[] info = line.split(":");
int index = 0;
System.out.println(line);
while(index < info.length){
System.out.println(info[index++]);
}
}

displaying data from .txt file [closed]

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Closed 4 years ago.
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need help, i want to display the name of the person who just logged in, here is my login code
public void Masuk(){
try {
String lokasi = "D:/settings.txt";
String username = txtUser.getText();
String password = txtPass.getText();
FileReader fr = new FileReader(lokasi);
BufferedReader br = new BufferedReader(fr);
String line, user, pass;
boolean isLoginSuccess = false;
while ((line = br.readLine()) != null) {
user = line.split(" ")[1].toLowerCase();
pass = line.split(" ")[2].toLowerCase();
if (user.equals(username) && pass.equals(password)) {
isLoginSuccess = true;
this.dispose();
new Main_Menu(this, rootPaneCheckingEnabled).show();
break;
}
}
if (!isLoginSuccess) {
JOptionPane.showMessageDialog(null, "USERNAME/PASSWORD WRONG", "WARNING!!", JOptionPane.WARNING_MESSAGE);
}
fr.close();
}catch(Exception e){
e.printStackTrace();
}
}
the login is in form, i used JDialog to dipslay the name of the person who just logged in(MainMenu), here is my MainMenu code right now
public void Berhasil(){
String data = "D:/Settings.txt";
try {
FileReader fr = new FileReader(data);
BufferedReader br = new BufferedReader(fr);
String line = br.readLine(),nama;
nama = line.split(" ")[0].toLowerCase();
String message = "Selamat datang "+ nama;
String text;
while ((line = br.readLine()) != null)
txtBerhasil.setText(""+message);
}
catch (FileNotFoundException fnfe) {
fnfe.getMessage();
}
catch (IOException ioe) {
ioe.getMessage();
}
}
the .txt file looks like this
Name Username Password
i only want to write the name of the person who just logged in

I'm assuming you want to read some text (the user's information) from a text file. There are several ways to do it. This is one way:
File file = new File("path/to/file.txt");
Scanner sc = new Scanner(file);
String thisLine = null;
while (sc.hasNextLine()){
thisLine = sc.nextLine();
}
Now you can do whatever you want with thisLine. Say you want the first word in the first line:
String[] words = thisLine.split(" ");
System.out.println(words[0]);
This would print the first word in the first line of your txt file. I used space as the separator but it actually depends on what separator you used in yout txt file when you were saving the info. For instance, you may want to use "\t" if tab was used as the separator.

why doesn't my file delete no matter why I do? [closed]

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Closed 6 years ago.
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public void removeLine(String s) throws IOException, FileNotFoundException{
File tempFile = new File("temp.txt");
FileInputStream reader = new FileInputStream(sharkFile);
Scanner scanner = new Scanner(reader);
BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile, true));
String currentLine;
while(scanner.hasNextLine()){
currentLine = scanner.nextLine();
String trimmedLine = currentLine.trim();
System.out.println(trimmedLine);
trimmedLine.equals(sharkName);
if(trimmedLine.equals(sharkName)) continue;
writer.write(currentLine + System.getProperty("line.separator"));
}
scanner.close();
scanner = null;
reader.close();
writer.flush();
writer.close();
writer = null;
System.gc();
if(!sharkFile.delete()){
System.out.println("Could not delete file d");
return;
}
if(!tempFile.renameTo(sharkFile)){
System.out.println("Could not rename file");
return;
}
}
I've gone through numerous threads on stackoverflow and have implemented those changes but my file just won't delete. Appreciate the help.

The File API is notoriously weak on explaining why something fail, e.g. File.delete() simply returns a boolean, and value false cannot explain why.
Use the new Path API instead.
Also, please (PLEASE!) use try-with-resources.
Scanner is slow, so better to use BufferedReader, and for writing the lines back with newlines, use a PrintWriter.
Path sharkPath = sharkFile.toPath();
Path tempPath = Paths.get("temp.txt");
Charset cs = Charset.defaultCharset();
try (BufferedReader reader = Files.newBufferedReader(sharkPath, cs);
PrintWriter writer = new PrintWriter(Files.newBufferedWriter(tempPath, cs, StandardOpenOption.CREATE, StandardOpenOption.APPEND, StandardOpenOption.WRITE)))) {
for (String currentLine; (currentLine = reader.readLine()) != null; ) {
String trimmedLine = currentLine.trim();
System.out.println(trimmedLine);
if (! trimmedLine.equals(sharkName))
writer.println(currentLine);
}
}
Files.delete(sharkPath); // throws descriptive exception if cannot delete
Files.move(tempPath, sharkPath); // throws exception if cannot move

Use below code, rename file before delete, it's appearing that you are accessing file name after delete:
try { //rename file first
tempFile.renameTo(sharkFile);
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Unable to rename.");
}
try {
sharkFile.delete();
}
catch(Exception e) {
JOptionPane.showMessageDialog(null, "Unable to delete.");
}

how to extract ipaddress,date&time,http:// in a log file using java [closed]

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Closed 8 years ago.
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if my logfile contains various lines like
sample data:/* 10.1.5.121 - d31f [17/Sep/2014:07:00:04 +0530] "POST http://webres3.qheal.ctmail.com/SpamResolverNG/SpamResolverNG.dll?DoNewRequest HTTP/1.0" 200 164 "HTTP" ""/*
how to extract ipaddress,date&time,http://... alone using Stringtokenizer concept.

File file = new File("test.txt");
String word = "abc,catch,profile";
Scanner scanner = null;
try {
scanner = new Scanner(file);
} catch (FileNotFoundException e) {
System.out.println("Error " + e);
}
// now read the file line by line
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
StringTokenizer st = new StringTokenizer(word, ",");
while (st.hasMoreTokens()) {
if (line.contains(st.nextToken())) {
System.out.println(line);
break;
}
}
}
scanner.close();`

I have made some modifications in the previous Code of mine.. Hope this will work for You..
File file = new File("FileTest.txt");
String[] findMe = {"abc","profile","catch"};
Scanner scanner = null;
try {
scanner = new Scanner(file);
} catch(FileNotFoundException e) {
e.printStackTrace();
}
int i=1;
ArrayList<String> neededLines = new ArrayList<String>();
while(scanner.hasNextLine()){
String line = scanner.nextLine();
for (String string : findMe) {
if(line.contains(string)){
if(!neededLines.contains(line))
neededLines.add(line);
}
}
}
System.out.println(neededLines);

How to replace the star {*} in text file with a number [duplicate]

This question already has answers here:
replace String with another in java
(7 answers)
Closed 3 years ago.
My contents of text file looks something like this
Synonyms of Fluster:
*panic
*perturb
*disconcert
*confuse
......
Now i wish to replace the * with numbers.Something like this.
output
Synonyms of Fluster:
1)panic
2)perturb
3)disconcert
4)confuse
......
Edit:
Integer count = 1;
File input = new File("C:\\Sample.txt");
File output = new File("C:\\output.txt");
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(input)));
Writer writer =new FileWriter(output);
while((line=reader.readLine())!=null)
{
if(line.contains("*"))
{
line.replace("*",count.toString() );
writer.write(line);
count++;
}
else
{
writer.write(line);
}
}
This is what i had tried before posting question here..But this doesn't seem to work.
Now can somebody help me out..?

You should write a JAVA program.
Here's something that may get you started (rough code):
BufferedReader br = new BufferedReader(new FileReader(file));
//start reading file line-by-line
while ((line = br.readLine()) != null) {
//replace * with whatever you want
// Use a counter to keep track of lines to give corresponding line number
String val = line.replace("*",counterVar.toString());
}
br.close();
Write back to file using BufferedWriter again, wrap it with PrintWriter if you wish to,
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("outputfile")));

Try something like this (Untested code):
try{
List<String> lines = Files.readAllLines(fileName, Charset.defaultCharset());
for (int i = 0; i< lines.size(); i++) {
lines.set(i, lines[i].replace("*", String.valueOf(i)));
}
} catch (IOException e) {
e.printStackTrace();
}
...//Then save the file