Develop Reference

Editing a text File in Java and saving it as a new text file

I have a text file with 5 lines, I wish to read in those lines and be able to number them 1 - 5, and save them in a different file. The numbers begin before the start of the line. I have tried to hard code in a loop to read in the number but I keep getting errors.
public class TemplateLab5Bronze {
static final String INPUT_FILE = "testLab5Bronze.txt";
static final String OUTPUT_FILE = "outputLab5Bronze.txt";
public static void main(String[] args) {
try {
FileReader in = new FileReader(INPUT_FILE);
PrintWriter out = new PrintWriter(OUTPUT_FILE);
System.out.println("Working");
BufferedReader inFile = new BufferedReader(in);
PrintWriter outFile = new PrintWriter(out);
outFile.print("Does this print?\n");
String trial = "Tatot";
outFile.println(trial);
System.out.format("%d. This is the top line\n", (int) 1.);
System.out.format("%d. \n", (int) 2.);
System.out.format("%d. The previous one is blank.\n", (int) 3.);
System.out.format("%d. Short one\n", (int) 4.);
System.out.format("%d. This is the last one.\n", (int) 5.);
/*if(int j = 1; j < 6; j++){
outFile.print( i + trial);
}*/
String line;
do {
line = inFile.readLine();
if (line != null) {
}
} while (line != null);
inFile.close();
in.close();
outFile.close();
} catch (IOException e) {
System.out.println("Doesnt Work");
}
System.out.print("Done stuff!");
}
}
This is all the code I have so far, excluding the import statements, the commented for loop is what I was trying to use. Is there another way to do this?

One way to do it is to add to the printWriter while looping through the existing file:
FileReader fr = new FileReader("//your//path//to//lines.txt");
BufferedReader br = new BufferedReader(fr);
try (PrintWriter writer = new PrintWriter("//your//other//path//newlines.txt", "UTF-8")) {
String line;
int num = 1;
while ((line = br.readLine()) != null) {
writer.println(num + ". " + line);
num++;
}
}
Note: I didn't put in any catch statements, but you might want to catch some/all of the following: FileNotFoundException, UnsupportedEncodingException, IOException

You don't need two PrintWriters. Use only one.
PrintWriter outFile = new PrintWriter(OUTPUT_FILE);
You can simply use a counter instead of a for loop (which you have incorrectly written as if - as mentioned by #Shirkam)
String line;
int count=1;
do {
line = inFile.readLine();
if (line != null) {
outFile.println( count++ +"." + line);
}
} while (line != null);
inFile.close();
This works fine at my end.

Read txt file and convert to array

I don't understand why this code won't read a .txt file then convert it to an array. I don't have the exact number of rows to begin with (to set the array) so I count the .txt files rows with a while loop.
This program should count the number of rows it imports then create a new array to copy & print the information to the console.
public class Cre{
public void openFile() throws IOException{
BufferedReader in = new BufferedReader(new FileReader("C:\\Users\\file.txt"));
String line = in.readLine();
int i=0;
String linecounterguy = "null";
int count = 0;
while(line!= null) { ///to count number of rows///
linecounterguy = in.readLine();
count += 1;
}
String[] array = new String[count+1];
String line1 = "try";
while(line!= null)
{
line1 = in.readLine();
System.out.println(line1);
}
in.close();
for (int j = 0; j < array.length-1 ; j++) {
linecounterguy = in.readLine();
System.out.println(array[j]);
}
}
}
Main Class
> public class JavaApplication8 {
>
> /**
> * #param args the command line arguments
> */
> public static void main(String[] args) throws IOException {
>
>
> Cre k = new Cre();
> k.openFile();
>
>
> } }

Here is a little method that will get you started with reading a text file into an array of strings. Hope this helps!
public String[] readLines(String filename) throws IOException {
FileReader fileReader = new FileReader(filename);
BufferedReader bufferedReader = new BufferedReader(fileReader);
List<String> lines = new ArrayList<String>();
String line = null;
while ((line = bufferedReader.readLine()) != null) {
lines.add(line);
}
bufferedReader.close();
return lines.toArray(new String[lines.size()]);
}

How to append multiple text in text file

I want the results from 'name' and 'code' to be inserted into log.txt file, but if I run this program only the name results gets inserted into .txt file, I cannot see code results appending under name. If I do System.outprintln(name) & System.outprintln(code) I get results printed in console but its not being inserted in a file.Can someone tell me what am I doing wrong?
Scanner sc = new Scanner(file, "UTF-8");
BufferedReader br = new BufferedReader(new FileReader(file));
PrintWriter out = new PrintWriter(new FileWriter("log.txt", true));
while ((line = br.readLine()) != null) {
if (line.contains("text1")) {
String[] splits = line.split("=");
String name = splits[2];
for (int i = 0; i < name.length(); i++) {
out.println(name);
}
}
if (line.contains("text2")) {
String[] splits = line.split("=");
String code = splits[2];
for (int i = 0; i < code.length(); i++) {
out.println(code);
}
}
out.close()
}
File looks like:
Name=111111111
Code=333,5555
Category-Warranty
Name=2222222
Code=111,22
Category-Warranty

Have a look at this code. Does that work for you?
final String NAME = "name";
final String CODE = "code";
BufferedReader br = new BufferedReader(new FileReader(file));
PrintWriter out = new PrintWriter(new FileWriter("log.txt", true));
while ((line = br.readLine()) != null) {
String[] splits = line.split("=");
String key = splits[0];
String value = splits[1];
if (key.equals(NAME) || key.equals(CODE)) {
out.println(value);
}
}
out.close();
You have a couple of problems in your code:
you never actually assign the variables name and code.
you close() your PrintWriter inside the while-loop, that means you will have a problem if you read more than one line.

I don't see why this wouldn't work, without seeing more of what you are doing:
BufferedReader br = new BufferedReader(new FileReader(file));
PrintWriter out = new PrintWriter(new FileWriter("log.txt", true));
while ((line = br.readLine()) != null) {
if (line.contains("=")) {
if (line.contains("text1")) {
String[] splits = line.split("=");
if (splits.length >= 2) {
out.println(splits[1]);
}
}
if (line.contains("text2")) {
String[] splits = line.split("=");
if (splits.length >= 2) {
out.println(splits[1]);
}
}
}
}
out.flush();
out.close();

Make sure the second if condition is satisfied i.e. the line String contains "text2".

Read text file line by line and store in a class?

I need some help with reading line by line from a file then put it into a class.
My idea is like this: I've saved everything in a text file, it's about 500 lines but this can change that's why I wan't the line number reader and then lnr/5 to get how many times I'll need to run the for loop. I wan't it to first take line 1,2,3,4,5 into a object, then 6,7,8,9,10 and so on. So basically I need each 5 lines go in seperatley.
Code:
public static void g_txt() {
LineNumberReader lnr;
String[] text_array = new String[500];
int nu = 0;
try {
lnr = new LineNumberReader(new FileReader(new File("test.txt")));
lnr.skip(Long.MAX_VALUE);
//System.out.println(lnr.getLineNumber());
lnr.close();
BufferedReader br = new BufferedReader(new FileReader("test.txt"));
String line;
while ((line = br.readLine()) != null) {
text_array[nu] = line;
nu++;
}
} catch (IOException e) {
}
}
as you can see, I now has it in an array. Now I need it to make so 1,2,3,4,5 and so on go in to this:
filmer[antalfilmer] = new FilmSvDe(line1);
filmer[antalfilmer].s_filmbolag(line2);
filmer[antalfilmer].s_producent(line3);
filmer[antalfilmer].s_tid(line4);
filmer[antalfilmer].s_betyg(line5);
filmer[antalfilmer].s_titel(line1);
then antalfilmer++.

public static void g_txt() {
String[] text_array = new String[5];
int nu = 0;
try {
BufferedReader br = new BufferedReader(new FileReader("test.txt"));
String line;
while ((line = br.readLine()) != null) {
text_array[nu] = line;
nu++;
if (nu == 5) {
nu = 0;
makeObject(text_array);
}
}
} catch (IOException e) {
}
}
private static void makeObject(String[] text_array) {
// do your object creation here
System.out.println("_________________________________________________");
for (String string : text_array) {
System.out.println(string);
}
System.out.println("_________________________________________________");
}
Try this.

Reading text from file and storing each word from every line into separate variables

I have a .txt file with the following content:
1 1111 47
2 2222 92
3 3333 81
I would like to read line-by-line and store each word into different variables.
For example: When I read the first line "1 1111 47", I would like store the first word "1" into var_1, "1111" into var_2, and "47" into var_3. Then, when it goes to the next line, the values should be stored into the same var_1, var_2 and var_3 variables respectively.
My initial approach is as follows:
import java.io.*;
class ReadFromFile
{
public static void main(String[] args) throws IOException
{
int i;
FileInputStream fin;
try
{
fin = new FileInputStream(args[0]);
}
catch(FileNotFoundException fex)
{
System.out.println("File not found");
return;
}
do
{
i = fin.read();
if(i != -1)
System.out.print((char) i);
} while(i != -1);
fin.close();
}
}
Kindly give me your suggestions. Thank You

public static void main(String[] args) throws IOException {
File file = new File("/path/to/InputFile");
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
String line = null;
while( (line = br.readLine())!= null ){
// \\s+ means any number of whitespaces between tokens
String [] tokens = line.split("\\s+");
String var_1 = tokens[0];
String var_2 = tokens[1];
String var_3 = tokens[2];
}
}

try {
BufferedReader fr = new BufferedReader(new InputStreamReader(new FileInputStream(file), "ASCII"));
while(true)
{
String line = fr.readLine();
if(line==null)
break;
String[] words = line.split(" ");//those are your words
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch(IOException e)
{
e.printStackTrace();
}
Hope this Helps!

Check out BufferedReader for reading lines. You'll have to explode the line afterwards using something like StringTokenizer or String's split.

import java.io.*;
import java.util.Scanner;
class Example {
public static void main(String[] args) throws Exception {
File f = new File("main.txt");
StringBuffer txt = new StringBuffer();
FileOutputStream fos = new FileOutputStream(f);
for (int i = 0; i < args.length; i++) {
txt.append(args[i] + " ");
}
fos.write(txt.toString().getBytes());
fos.close();
FileInputStream fis = new FileInputStream("main.txt");
InputStreamReader input = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(input);
String data;
String result = new String();
StringBuffer txt1 = new StringBuffer();
StringBuffer txt2 = new StringBuffer();
File f1 = new File("even.txt");
FileOutputStream fos1 = new FileOutputStream(f1);
File f2 = new File("odd.txt");
FileOutputStream fos2 = new FileOutputStream(f2);
while ((data = br.readLine()) != null) {
result = result.concat(data);
String[] words = data.split(" ");
for (int j = 0; j < words.length; j++) {
if (j % 2 == 0) {
System.out.println(words[j]);
txt1.append(words[j] + " ");
} else {
System.out.println(words[j]);
txt2.append(words[j] + " ");
}
}
}
fos1.write(txt1.toString().getBytes());
fos1.close();
fos2.write(txt2.toString().getBytes());
fos2.close();
br.close();
}
}