Develop Reference

finding character count between two special symbols

Am trying to find the character count between = and \n new line character using below java code. But \n is not considering in my case.
am using import org.apache.commons.lang3.StringUtils; package
Please find my below java code.
public class CharCountInLine {
public static void main(String[] args)
{
BufferedReader reader = null;
try
{
reader = new BufferedReader(new FileReader("C:\\wordcount\\sample.txt"));
String currentLine = reader.readLine();
String[] line = currentLine.split("=");
while (currentLine != null ){
String res = StringUtils.substringBetween(currentLine, "=", "\n"); // \n is not working.
if(res != null) {
System.out.println("line -->"+res.length());
}
currentLine = reader.readLine();
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
reader.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
Please find my sample text file.
sample.txt
Karthikeyan=123456
sathis= 23546
Arun = 23564

Well, you're reading the string using readLine(), which according to the Javadoc (emphasis mine):
Returns:
A String containing the contents of the line, not including
any line-termination characters, or null if the end of the stream has
been reached
So your code doesn't work because the string does not contain a newline character.
You can address this in a number of ways:
Use StringUtils.substringAfter() instead of StringUtils.substringBetween().
If it meets the requirements, treat your file as a Java properties file so you don't need to parse it yourself.
Use String.split().
Use String.lastIndexOf().
Some simple regex matching and grouping.

You don't need to change how you read the lines, simply change your logic to extract the text after =.
Pattern p = Pattern.compile("(?:.+)=(.+)$");
Matcher m = p.matcher("Karthikeyan=123456");
if (m.find()) {
System.out.println(m.group(1).length());
}
No need for Apache StringUtils either, simple Java regex will do. If you don't want to count whitespace, trim the string before calling length().
Alternatively, you can also split the line around = as discussed here.
10x simpler code:
Path p = Paths.get("C:\\wordcount\\sample.txt");
Files.lines(p)
.forEach { line ->
// Put the above code here
}

Java - Groovy : regex parse text block

I know that this is a common question and I've been through a lot of forums to figure out whats the problem in my code.
I have to read a text file with several blocks in the following format:
import com.myCompanyExample.gui.Layout
/*some comments here*/
#Layout
LayoutModel currentState() {
MyBuilder builder = new MyBuilder()
form example
title form{
row_1
row_1
row_n
}
return build.get()
}
#Layout
LayoutModel otherState() {
....
....
return build.get()
}
I have this code to read all the file and I'd like to extract each block between the keyword "#Layout" and the keyword "return". I need also to catch all newline so later I'll be able to split each matched block into a list
private void myReadFile(File fileLayout){
String line = null;
StringBuilder allText = new StringBuilder();
try{
FileReader fileReader = new FileReader(fileLayout);
BufferedReader bufferedReader = new BufferedReader(fileReader);
while((line = bufferedReader.readLine()) != null) {
allText.append(line)
}
bufferedReader.close();
}
catch(FileNotFoundException ex) {
System.out.println("Unable to open file");
}
catch(IOException ex) {
System.out.println("Error reading file");
}
Pattern pattern = Pattern.compile("(?s)#Layout.*?return",Pattern.DOTALL);
Matcher matcher = pattern.matcher(allText);
while(matcher.find()){
String [] layoutBlock = (matcher.group()).split("\\r?\\n")
for(index in layoutBlock){
//check each line of the current block
}
}
layoutBlock returns size=1

I think this can potentially be a so called XY problem anyway...if the groovy source is composed only by #Layout annotated blocks of code you can use a tempered greedy token to select till the next annotation (view online demo).
Change the pattern loc as this:
Pattern pattern = Pattern.compile( "#Layout(?:(?!#Layout).)*", Pattern.DOTALL );
PS: the dotall flag (?s) inside the regex and the parameter Pattern.DOTALL do the same thing (enable the so called multiline mode), use only one of them indifferently.
UPDATE
I tried your code, the problem (preserving newline) is in the method you use to slurp the file (bufferedReader.readline() remove the newline at the end of the string).
Simply readd a newline when append to allText:
String ln = System.lineSeparator();
while((line = bufferedReader.readLine()) != null) {
allText.append(line + ln);
}
Or you can replace all the code to slurp the file with this:
import java.nio.file.Files;
import java.nio.file.Paths;
//can throw an IOException
String filePath = "/path/to/layout.groovy";
String allText = new String(Files.readAllBytes(Paths.get(filePath)),StandardCharsets.UTF_8);

Reading textfile line by line and put in object array

I have to make an EPG app using java, but I am kind of new in programming and it's due tomorrow and it's still not working properly.
I have a question about a small part: I have to read the programs from a text file. Each line contains multiple things, the channel, the title of the program, a subtitle, a category, etcetera.
I have to make sure that I can read the separate parts of each line, but it's not really working, it's only printing the parts from the first line.
I am trying, but I can't find why it's not printing all the parts from all the lines in stead of printing only the parts from the first line. Here's the code:
BufferedReader reader = new BufferedReader(newFileReader(filepath));
while (true) {
String line = reader.readLine();
if (line == null) {
break;
}
}
String[] parts = line.split("\\|", -1);
for(int i = 0; i < parts.length; i++) {
System.out.println(parts[i]);
}
reader.close();
Does anybody know how to get all the lines in stead of only the first?
Thank you!

readLine() only reads one line, so you need to loop it, as you said.
BUT with reading to the String inside of the while loop you always overwrite that String.
You would need to declare the String above the while loop that you can access it from outside, too.
BTW, it seems that your braces for the if don't match.
Anyway, I'd fill the information into an ArrayList, look below:
List<String> list = new ArrayList<>();
String content;
// readLine() and close() may throw errors, so they require you to catch it…
try {
while ((content = reader.readLine()) != null) {
list.add(content);
}
reader.close();
} catch (IOException e) {
// This just prints the error log to the console if something goes wrong
e.printStackTrace();
}
// Now proceed with your list, e.g. retrieve first item and split
String[] parts = list.get(0).split("\\|", -1);
// You can simplify the for loop like this,
// you call this for each:
for (String s : parts) {
System.out.println(s);
}

Use apache commons lib
File file = new File("test.txt");
List<String> lines = FileUtils.readLines(file);

As ArrayList is Dynamic,try,
private static List<String> readFile(String filepath) {
String line = null;
List<String> list = new ArrayList<String>();
try {
BufferedReader reader = new BufferedReader(new FileReader(filepath));
while((line = reader.readLine()) != null){
list.add(line);
}
} catch (Exception e) {
e.printStackTrace();
}
return list;
}

Assigning part of txt file to java variable

I have a txt file with the following output:
"CN=COUD111255,OU=Workstations,OU=Mis,OU=Accounts,DC=FLHOSP,DC=NET"
What I'm trying to do is read the COUD111255 part and assign it to a java variable. I assigned ldap to sCurrentLine, but I'm getting a null point exception. Any suggestions.
try (BufferedReader br = new BufferedReader(new FileReader("resultofbatch.txt")))
{
final Pattern PATTERN = Pattern.compile("CN=([^,]+).*");
try {
while ((sCurrentLine = br.readLine()) != null) {
//Write the function you want to do, here.
String[] tokens = PATTERN.split(","); //This will return you a array, containing the string array splitted by what you write inside it.
//should be in your case the split, since they are seperated by ","
}
System.out.println(sCurrentLine);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
}
});

You just need to read data from a file line by line and assign the line to your variable str. Refer to following link:
How to read a large text file line by line using Java?

Your code is almost correct. You are writing this string to standard output - what for? If I understand you right, what you need is simply this:
private static final Pattern PATTERN = Pattern.compile("CN=([^,]+).*");
public static String solve(String str) {
Matcher matcher = PATTERN.matcher(str);
if (matcher.matches()) {
return matcher.group(1);
} else {
throw new IllegalArgumentException("Wrong string " + str);
}
}
This call
solve("CN=COUD111255,OU=Workstations,OU=Mis,OU=Accounts,DC=FLHOSP,DC=NET")
gave me "COUD111255" as answer.

To read from .txt, use BufferedReader. To create a one, write:
BufferedReader br = new BufferedReader(new FileReader("testing.txt"));
testing.txt is the name of the txt that you're reading and must be in your java file. After initializing, you must continue as:
while ((CurrentLine = br.readLine()) != null) {
//Write the function you want to do, here.
String[] tokens = CurrentLine.split(","); //This will return you a array, containing the string array splitted by what you write inside it.
//should be in your case the split, since they are seperated by ","
}
You got tokens array which is = [CN=COUD111255,OU=Workstations OU=Mis,OU=Accounts,DC=FLHOSP,DC=NET].
So, now take the 0th element of array and make use of it. You got the CN=COUD111255, now! Leaving here not to give whole code.
Hope that helps !

Java extract text from text file from a certain point on the text

I have created a method with BufferedReader that opens a text file created previously by the program and extracts some characters. My problem is that it extracts the whole line and I want to extract only after a specified character, the :.
Here is my try/catch block:
try {
InputStream ips = new FileInputStream("file.txt");
InputStreamReader ipsr = new InputStreamReader(ips);
BufferedReader br1 = new BufferedReader(ipsr);
String ligne;
while((ligne = br1.readLine()) != null) {
if(ligne.startsWith("Identifiant: ")) {
System.out.println(ligne);
id = ligne;
}
if(ligne.startsWith("Pass: ")) {
System.out.println(ligne);
pass = ligne;
}
}
System.out.println(ligne);
System.out.println(id);
System.out.println(pass);
br1.close();
} catch (Exception ex) {
System.err.println("Error. "+ex.getMessage());
}
At the moment, I return to my String id the entire ligne, and same for pass – by the way, all the sysout are tests and are useless there.
If anybody knows how to send to id the line after the :and not the entire line, I probably searched bad, but google wasn't my friend.

Assuming there's only one : symbol in the string you can go with
id = ligne.substring(ligne.lastIndexOf(':') + 1);

Use StringUtils
StringUtils.substringAfter(id ,":"),

Why don't you try to do a split() on ligne?
If you use String[] splittedLigne = ligne.split(":");, you will have the following in splittedLigne:
splittedLigne[0] -> What is before the :
splittedLigne[1] -> What is after the :
This will give you what you need for every line. Also, this will work for you if you have more than one :.