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Can't insertRow which contains Strings from file [duplicate]

This question already has answers here:
How do I print my Java object without getting "SomeType#2f92e0f4"?
(13 answers)
Why does println(array) have strange output? ("[Ljava.lang.String;#3e25a5") [duplicate]
(6 answers)
Closed 3 years ago.
I'm trying to read from file and insert in a row, after inserting I'm having this :
[Ljava.lang.String;#7f059c04
[Ljava.lang.String;#855c8af
The Listener, and BufferRead and Inserting file read.
String filepath = "C:\\imdoingjava\\Java3-Projet\\valuesarticles.txt";
File file = new File(filepath);
private class okListener implements ActionListener{
public void actionPerformed(ActionEvent event){
try{
BufferedReader br = new BufferedReader(new FileReader(file));
Object [] tableLines = br.lines().toArray();
for(int i=0; i<tableLines.length; i++){
String line = tableLines[i].toString().trim();
String [] dataRow = line.split("\n");
model.insertRow(0, new Object[] {"", "", dataRow ,""});
}
}
catch(FileNotFoundException fo){
fo.getMessage();
}
}
If I used model.insertRow(0, dataRow); which I commented it, it works but it inserts it in the first column, and I want it in the third.

Java how to read a file line by line and change the specific part of the line [duplicate]

This question already has answers here:
Modify the content of a file using Java
(6 answers)
Closed 3 years ago.
I am new at java and teacher gave us a project homework. I have to implement read the file line by line, slice the lines at the comma and store the parts at a multidimensional array, change the specific part of the line (I want to change the amount).
The given file:
product1,type,amount
product2,type,amount
product3,type,amount
product4,type,amount
product5,type,amount
I tried this code but I couldn't change the specific part.
BufferedReader reader;
int j=0;
int i=0;
try {
reader = new BufferedReader(new FileReader("file.txt"));
String line = reader.readLine();
while (line != null) {
j++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
String total_length[][]=new String[j][3];
try {
reader = new BufferedReader(new FileReader("file.txt"));
String line = reader.readLine();
while (line != null) {
line = reader.readLine();
String[] item = line.split(",");
total_length[i][0]=item[0];
total_length[i][1]=item[0];
total_length[i][2]=item[0];
i++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
Thanks a lot!

First, you need to read the file. There are plenty of way to do it, one of them is:
BufferedReader s = new BufferedReader(new FileReader("filename"));
Which allows you to do s.readLine() to read it line by line.
You can use a while loop to read it until the end. Note that readLine will return null if you reach the end of the file.
Then, for each line, you want to split them with the coma. You can use the split method of Strings:
line.split(",");
Putting it all together, and using a try-catch for IOException, you get:
List<String[]> result = new ArrayList<>();
try (BufferedReader s = new BufferedReader(new FileReader("filename"))) {
String line;
while ((line = s.readLine()) != null) {
result.add(line.split(","));
}
} catch (IOException e) {
// Handle IOExceptions here
}
If you really need a two dimensional array at the end, you can do:
String[][] array = new String[0][0];
array = result.toArray(array);
You then have read the file in the format you wanted, you can now modify the data that you parsed.

How to read a textfile and saving it into an Array? [duplicate]

This question already has answers here:
Java: Reading a file into an array
(5 answers)
Closed 4 years ago.
i would like to build a text data-cleaner in Java, which
cleans the text from Smileys and other special charakter. I wrote a text reader,
but he stops after 3/4 of Line 97 and i just don't know why he does it? Normally he should read the complete text file (ca. 110.000 Lines) and then stop. It would be really nice if could show me where my mistake is.
public class FileReader {
public static void main(String[] args) {
String[] data = null;
int i = 0;
try {
Scanner input = new Scanner("C://Users//Alex//workspace//Cleaner//src//Basis.txt");
File file = new File(input.nextLine());
input = new Scanner(file);
while (input.hasNextLine()) {
String line = input.nextLine();
System.out.println(line);
data[i] = line;
i++;
}
input.close();
}
catch (Exception ex) {
ex.printStackTrace();
}
System.out.println(data[97]);
}
}

Your mistake is here:
String[] data = null;
I would expect this code to throw null pointer exception...
You can use ArrayList instead of plain array if you want to have dynamic re-sizing

Reading text file into arraylist

I really new to Java so I'm having some trouble figuring this out. So basically I have a text file that looks like this:
1:John:false
2:Bob:false
3:Audrey:false
How can I create an ArrayList from the text file for each line?

Read from a file and add each line into arrayList. See the code for example.
public static void main(String[] args) {
ArrayList<String> arr = new ArrayList<String>();
try (BufferedReader br = new BufferedReader(new FileReader(<your_file_path>)))
{
String sCurrentLine;
while ((sCurrentLine = br.readLine()) != null) {
arr.add(sCurrentLine);
}
} catch (IOException e) {
e.printStackTrace();
}
}

While the answer above me works, here's another way to do it. Make sure to import java.util.Scanner.
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<String>();
Scanner scan = new Scanner("YOURFILE.txt");
while(scan.hasNextLine()){
list.add(scan.nextLine());
}
scan.close();
}

If you know how to read a file line by line, either by using Scanner or by using BufferedReader then reading a text file into ArrayList is not difficult for you. All you need to do is read each line and store that into ArrayList, as shown in following example:
BufferedReader bufReader = new BufferedReader(new
FileReader("file.txt"));
ArrayList<String> listOfLines = new ArrayList<>);
String line = bufReader.readLine(); while (line != null)
{
listOfLines.add(line);
line = bufReader.readLine();
}
bufReader.close();
Just remember to close the BufferedReader once you are done to prevent resource leak, as you don't have try-with-resource statement

This will be help to you.
List<String> list = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new FileReader("list.txt"));
String line;
while ((line = reader.readLine()) != null) {
list.add(line);
}
reader.close();
Then you can access those elements in the arraylist.

java 8 lets you do this
String fileName = "c://lines.txt";
List<String> list = new ArrayList<>();
try (Stream<String> stream = Files.lines(Paths.get(fileName))) {
list = stream
.map(String::toUpperCase)
.collect(Collectors.toList());
} catch (IOException e) {
e.printStackTrace();
}
list.forEach(System.out::println);

Java - Create String Array from text file [duplicate]

This question already has answers here:
Java: Reading a file into an array
(5 answers)
Closed 1 year ago.
I have a text file like this :
abc def jhi
klm nop qrs
tuv wxy zzz
I want to have a string array like :
String[] arr = {"abc def jhi","klm nop qrs","tuv wxy zzz"}
I've tried :
try
{
FileInputStream fstream_school = new FileInputStream("text1.txt");
DataInputStream data_input = new DataInputStream(fstream_school);
BufferedReader buffer = new BufferedReader(new InputStreamReader(data_input));
String str_line;
while ((str_line = buffer.readLine()) != null)
{
str_line = str_line.trim();
if ((str_line.length()!=0))
{
String[] itemsSchool = str_line.split("\t");
}
}
}
catch (Exception e)
{
// Catch exception if any
System.err.println("Error: " + e.getMessage());
}
Anyone help me please....
All answer would be appreciated...

If you use Java 7 it can be done in two lines thanks to the Files#readAllLines method:
List<String> lines = Files.readAllLines(yourFile, charset);
String[] arr = lines.toArray(new String[lines.size()]);

Use a BufferedReader to read the file, read each line using readLine as strings, and put them in an ArrayList on which you call toArray at end of loop.

Based on your input you are almost there. You missed the point in your loop where to keep each line read from the file. As you don't a priori know the total lines in the file, use a collection (dynamically allocated size) to get all the contents and then convert it to an array of String (as this is your desired output).
Something like this:
String[] arr= null;
List<String> itemsSchool = new ArrayList<String>();
try
{
FileInputStream fstream_school = new FileInputStream("text1.txt");
DataInputStream data_input = new DataInputStream(fstream_school);
BufferedReader buffer = new BufferedReader(new InputStreamReader(data_input));
String str_line;
while ((str_line = buffer.readLine()) != null)
{
str_line = str_line.trim();
if ((str_line.length()!=0))
{
itemsSchool.add(str_line);
}
}
arr = (String[])itemsSchool.toArray(new String[itemsSchool.size()]);
}
Then the output (arr) would be:
{"abc def jhi","klm nop qrs","tuv wxy zzz"}
This is not the optimal solution. Other more clever answers have already be given. This is only a solution for your current approach.

This is my code to generate random emails creating an array from a text file.
import java.io.*;
public class Generator {
public static void main(String[]args){
try {
long start = System.currentTimeMillis();
String[] firstNames = new String[4945];
String[] lastNames = new String[88799];
String[] emailProvider ={"google.com","yahoo.com","hotmail.com","onet.pl","outlook.com","aol.mail","proton.mail","icloud.com"};
String firstName;
String lastName;
int counter0 = 0;
int counter1 = 0;
int generate = 1000000;//number of emails to generate
BufferedReader firstReader = new BufferedReader(new FileReader("firstNames.txt"));
BufferedReader lastReader = new BufferedReader(new FileReader("lastNames.txt"));
PrintWriter write = new PrintWriter(new FileWriter("emails.txt", false));
while ((firstName = firstReader.readLine()) != null) {
firstName = firstName.toLowerCase();
firstNames[counter0] = firstName;
counter0++;
}
while((lastName= lastReader.readLine()) !=null){
lastName = lastName.toLowerCase();
lastNames[counter1]=lastName;
counter1++;
}
for(int i=0;i<generate;i++) {
write.println(firstNames[(int)(Math.random()*4945)]
+'.'+lastNames[(int)(Math.random()*88799)]+'#'+emailProvider[(int)(Math.random()*emailProvider.length)]);
}
write.close();
long end = System.currentTimeMillis();
long time = end-start;
System.out.println("it took "+time+"ms to generate "+generate+" unique emails");
}
catch(IOException ex){
System.out.println("Wrong input");
}
}
}

You can read file line by line using some input stream or scanner and than store that line in String Array.. A sample code will be..
File file = new File("data.txt");
try {
//
// Create a new Scanner object which will read the data
// from the file passed in. To check if there are more
// line to read from it we check by calling the
// scanner.hasNextLine() method. We then read line one
// by one till all line is read.
//
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
//store this line to string [] here
System.out.println(line);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}

Scanner scanner = new Scanner(InputStream);//Get File Input stream here
StringBuilder builder = new StringBuilder();
while (scanner.hasNextLine()) {
builder.append(scanner.nextLine());
builder.append(" ");//Additional empty space needs to be added
}
String strings[] = builder.toString().split(" ");
System.out.println(Arrays.toString(strings));
Output :
[abc, def, jhi, klm, nop, qrs, tuv, wxy, zzz]
You can read more about scanner here

You can use the readLine function to read the lines in a file and add it to the array.
Example :
File file = new File("abc.txt");
FileInputStream fin = new FileInputStream(file);
BufferedReader reader = new BufferedReader(fin);
List<String> list = new ArrayList<String>();
while((String str = reader.readLine())!=null){
list.add(str);
}
//convert the list to String array
String[] strArr = Arrays.toArray(list);
The above array contains your required output.