Develop Reference

BufferedReader not reading the entire file and not exiting the loop

I have ini file that to be read in my application but the problem is it is not reading the entire file and it stucks in the while loop.
My code:
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
String line = br.readLine();
Properties section = null;
while(line!=null){
if(line.startsWith("[") && line.endsWith("]")){
section = new Properties();
this.config.put(line.substring(1, line.length() - 1), section);
}else{
String key = line.split("=")[0];
String value = line.split("=")[1];
section.setProperty(key, value);
}
line = br.readLine();
System.out.println(line);
// To continue reading newline.
//if i remove this, it will not continue reading the second header
if(line.equals("")){
line = br.readLine();
}
}
System.out.println("Done"); // Not printing this.
This is what inside the ini file. The newlines are included so I add if the line.equals("").
[header]
key=value
[header2]
key1=value1
key2=value2
[header3]
key=value
// -- stops here
//this newlines are included.
#Some text // stops here when I remove all the newlines in the ini file.
#Some text
Output:
[header]
key=value
[header2]
key1=value1
key2=value2
[header3]
key=value
//whitespace
//whitespace
UPDATE:
I remove all the newlines in the ini file but still not reading the entire file.

Unless there's something you've not included in this post the logic won't get stuck in the loop... If the file you're using looks exactly like what you've posted, it'll hit either a blank line(because you're only skipping 1 blank) or one of the lines starting "#" and get an ArrayIndexOutOfBoundsException because those lines don't contain an "="... Simplify your while loop to this and the ArrayIndexOutOfBoundsExceptions wont occur and it'll process the full file:
Properties section = null;
String line = null;
while ((line = br.readLine()) != null) {
if (line.startsWith("[") && line.endsWith("]")) {
section = new Properties();
this.config.put(line.substring(1, line.length() - 1), section);
} else if (line.contains("=") && !line.startsWith("#")) {
String[] keyValue = line.split("=");
section.setProperty(keyValue[0], keyValue[1]);
}
}
Notice that I'm doing a line.contains("=") so that blank lines and lines beginning # are skipped over...

reading input from file until specific word is read

i am writing a java program to read a file and print output to another string variable.which is working perfectly as intended using is code.
{
String key = "";
FileReader file = new FileReader("C:/Users/raju/Desktop/input.txt");
BufferedReader reader = new BufferedReader(file);
String line = reader.readLine();
while (line != null) {
key += line;
line = reader.readLine();
}
System.out.println(key); //this prints contents of .txt file
}
this prints whole text in the file.But i want to only print the lines till word END is encountered in file.
example: if input.txt file contains following text : this test file END extra in
it should print only :
this test file

Just do a simple indexOf to see where it is and if it exists in the line. If the instance is found one option would be using substring to cut off everything up until the index of the keyword. For a bit more control though try using java regular expressions.
String key = "";
FileReader file = new FileReader("C:/Users/raju/Desktop/input.txt");
BufferedReader reader = new BufferedReader(file);
String line = reader.readLine();
while ((line = reader.readLine()) != null && line.indexOf("Keyword to look for") == -1)
key += line;
System.out.println(key);

I am not sure why it needs to be any more complicated than this:
BufferedReader re = new BufferedReader(new InputStreamReader(System.in));
while (true) {
String str = re.readLine();
if (str.equals("exit")) break;
// whatever other code.
}

You can do it in many ways. one of them is using indexOf method to specify the start index of "END" in input and then using subString method.
for more information, read documentation of String calss. HERE

This will work for your issue.
public static void main(String[] args) throws IOException {
String key = "";
FileReader file = new FileReader("/home/halil/khalil.txt");
BufferedReader reader = new BufferedReader(file);
String line = reader.readLine();
while (line != null) {
key += line;
line = reader.readLine();
} String output = "";
if(key.contains("END")) {
output = key.split("END")[0];
System.out.println(output);
}
}

You have to change your logic to check if the line contains "END".
If END not found in a line, add the line to key stringin your program
If yes, split that line into word array, read the line till you encounter the word "END" and append it to your key string. Consider using Stringbuilder for key.
while (line != null) {
line = reader.readLine();
if(!line.contains("END")){
key += line;
}else{
//Note that you can use split logic like below, or use java substring
String[] words = line.split("");
for(String s : words){
if(s.equals("END")){
return key;
}
key += s;
}
}
}

Readline() reads only first line

I need to read a text file and split using a common text in the lines, and print a part of the split text. This works fine but only does this for the first line in the text.
However, if I print lines without the split part, it prints correctly. Please what am I doing wrong?
File sample: (I want to split by "words")
Line 1 This text is of length: 7 words. I need to learn how to program.
Line 2 Now we have text of length: 3 words. No matter what the words are, I must program
FileInputStream fis = new FileInputStream(fin);
//Construct BufferedReader from InputStreamReader
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String line = null;
ArrayList<String> txt1 = new ArrayList<>();
while ((line = br.readLine()) != null) {
String[] pair = line.split("words");
txt1.add(pair[1]);
System.out.println(txt1);
//System.out.println(line);
}
br.close();

Given the following unit test simulating the input of a file via a StringInputStream:
#Test
public void test() throws IOException
{
String fileContent = "This text is of length: 7 words.\r\nI need to learn how to program and one day.";
StringInputStream stream = new StringInputStream(fileContent);
BufferedReader br = new BufferedReader(new InputStreamReader(stream));
String line = null;
ArrayList<String> txt1 = new ArrayList<>();
while ((line = br.readLine()) != null) {
String[] pair = line.split("words");
txt1.add(pair[1]);
System.out.println(txt1);
//System.out.println(line);
}
}
The first line will be split into
"This text is of length: 7 " and
"."
Since you put item [1] into the array list, it'll just contain a single dot.
The second line will be split into
"I need to learn how to program and one day."
only. There is no second item, so accessing [1] results in a ArrayIndexOutOfBoundsException.

How to write new line character to a file in Java

I have a string that contains new lines. I send this string to a function to write the String to a text file as:
public static void writeResult(String writeFileName, String text)
{
try
{
FileWriter fileWriter = new FileWriter(writeFileName);
BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
bufferedWriter.write(text);
// Always close files.
bufferedWriter.close();
}
catch(IOException ex) {
System.out.println("Error writing to file '"+ writeFileName + "'");}
} //end writeResult function
But when I open the file, I find it without any new lines.
When I display the text in the console screen, it is displayed with new lines. How can I write the new line character in the text file.
EDIT:
Assume this is the argument text that I sent to the function above:
I returned from the city about three o'clock on that
may afternoon pretty well disgusted with life.
I had been three months in the old country, and was
How to write this string as it is (with new lines) in the text file. My function write the string in one line. Can you provide me with a way to write the text to the file including new lines ?
EDIT 2:
The text is originally in a .txt file. I read the text using:
while((line = bufferedReader.readLine()) != null)
{
sb.append(line); //append the lines to the string
sb.append('\n'); //append new line
} //end while
where sb is a StringBuffer

In EDIT 2:
while((line = bufferedReader.readLine()) != null)
{
sb.append(line); //append the lines to the string
sb.append('\n'); //append new line
} //end while
you are reading the text file, and appending a newline to it. Don't append newline, which will not show a newline in some simple-minded Windows editors like Notepad. Instead append the OS-specific line separator string using:
sb.append(System.lineSeparator()); (for Java 1.7 and 1.8)
or
sb.append(System.getProperty("line.separator")); (Java 1.6 and below)
Alternatively, later you can use String.replaceAll() to replace "\n" in the string built in the StringBuffer with the OS-specific newline character:
String updatedText = text.replaceAll("\n", System.lineSeparator())
but it would be more efficient to append it while you are building the string, than append '\n' and replace it later.
Finally, as a developer, if you are using notepad for viewing or editing files, you should drop it, as there are far more capable tools like Notepad++, or your favorite Java IDE.

SIMPLE SOLUTION
File file = new File("F:/ABC.TXT");
FileWriter fileWriter = new FileWriter(file,true);
filewriter.write("\r\n");

The BufferedWriter class offers a newLine() method. Using this will ensure platform independence.

bufferedWriter.write(text + "\n"); This method can work, but the new line character can be different between platforms, so alternatively, you can use this method:
bufferedWriter.write(text);
bufferedWriter.newline();

Split the string in to string array and write using above method (I assume your text contains \n to get new line)
String[] test = test.split("\n");
and the inside a loop
bufferedWriter.write(test[i]);
bufferedWriter.newline();

This approach always works for me:
String newLine = System.getProperty("line.separator");
String textInNewLine = "this is my first line " + newLine + "this is my second
line ";

Put this code wherever you want to insert a new line:
bufferedWriter.newLine();

PrintWriter out = null; // for writting in file
String newLine = System.getProperty("line.separator"); // taking new line
out.print("1st Line"+newLine); // print with new line
out.print("2n Line"+newLine); // print with new line
out.close();

Here is a snippet that gets the default newline character for the current platform.
Use
System.getProperty("os.name") and
System.getProperty("os.version").
Example:
public static String getSystemNewline(){
String eol = null;
String os = System.getProperty("os.name").toLowerCase();
if(os.contains("mac"){
int v = Integer.parseInt(System.getProperty("os.version"));
eol = (v <= 9 ? "\r" : "\n");
}
if(os.contains("nix"))
eol = "\n";
if(os.contains("win"))
eol = "\r\n";
return eol;
}
Where eol is the newline

Counting Words and Newlines In A File Using Java?

I am writing a small java app which will scan a text file for any instances of particular word and need to have a feature whereby it can report that an instance of the word was found to be the 14th word in the file, on the third line, for example.
For this i tried to use the following code which i thought would check to see whether or not the input was a newline (\n) character and then incerement a line variable that i created:
FileInputStream fileStream = new FileInputStream("src/file.txt");
DataInputStream dataStream = new DataInputStream(fileStream);
BufferedReader buffRead = new BufferedReader(new InputStreamReader(dataStream));
String strLine;
String Sysnewline = System.getProperty("line.separator");
CharSequence newLines = Sysnewline;
int lines = 1;
while ((strLine = buffRead.readLine()) != null)
{
if(strLine.contains(newLines))
{
System.out.println("Line Found");
lines++;
}
}
System.out.println("Total Number Of Lines In File: " + lines);
This does not work for, it simply display 0 at the end of this file. I know the data is being placed into strLine during the while loop as if i change the code slightly to output the line, it is successfully getting each line from the file.
Would anyone happen to know the reason why the above code does not work?

Read the javadocs for readLine.
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

readLine() strips newlines. Just increment every iteration of the loop. Also, you're overcomplicating your file reading code. Just do new BufferedReader(new FileReader("src/file.txt"))