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Thread: Writing to a text file

  1. #1
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    Default Writing to a text file

    Hello,

    I'm trying to write to a text file but it's not working and I don't see why. I may be doing this all wrong, I don't know. My code is below, it is still at a skeleton stage.

    The Function InitPerformancesReport correctly creates the file and when I get to WriteToPerformancesReport, it writes "Written to file" to the console so it is not throwing an exception apparently. However, nothing is written to the file. I even tried to add an out.flush(); and out.write(); inside the function just for testing purposes but to no avail. I end up with a 0 byte file. What am I doing wrong ?

    Thank you for your help!!
    public class Monitoring {
    	private static DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH_mm_ss");
    	private static LocalDateTime now;
    	private static String perfLogFile;
    	private static FileWriter writer;
    	private static BufferedWriter out;
     
    	public static void InitPerformancesReport(String suffix) {
    		now = LocalDateTime.now();
    		perfLogFile = dtf.format(now) + "_" + suffix + ".log";
    		String directoryName = "D:\\TempsDeResponse";
    		File directory = new File(directoryName);
    		File file = new File(directoryName + "\\" + perfLogFile);
     
    		if (!directory.exists()) {
    			directory.mkdir();
    		}
     
    		try {
    			if (file.createNewFile()) {
    				System.out.println("File is created");
    			}
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot create file");
    			e.printStackTrace();
    		}
     
    		try {
    			writer = new FileWriter(perfLogFile);
    			out = new BufferedWriter(writer);
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot create writer");
    			e.printStackTrace();
    		}
    	}
     
    	public static void WriteToPerformancesReport(String transactionName, Long transactionTime) {
    		try {
     
    			out.write("TEST");
    			out.newLine();
    			System.out.println("Written to file");
     
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot write to file");
    			e.printStackTrace();
    		}
     
    	}
     
    	public static void ExportPerformancesReport() {
    		try {
    			out.close();
    			writer.close();
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}		
    }
    Last edited by Norm; March 12th, 2018 at 12:20 PM. Reason: Added code tag

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Writing to a text file

    I've added code tags.
    Please next time wrap your code with code tags:

    [code]
    **YOUR CODE GOES HERE**
    [/code]

    to get highlighting and preserve formatting.

    The code needs import statements and a main() method so that it can be compiled and executed for testing.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Writing to a text file

    Quote Originally Posted by Norm View Post
    I've added code tags.
    Please next time wrap your code with code tags:

    [code]
    **YOUR CODE GOES HERE**
    [/code]

    to get highlighting and preserve formatting.

    The code needs import statements and a main() method so that it can be compiled and executed for testing.


    Hello,

    Sorry about the code tags. This was my first post and I didn't know about them.

    Yeah, I guess it does need import statements and a main() method.

    --- Update ---

    With imports and main(). It creates the file but it doesn't write in it. Obviously, I'm doing something wrong but I don't know what :-(

    import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.time.LocalDateTime;
    import java.time.format.DateTimeFormatter;
     
    public class Monitoring {
     
    	private static DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH_mm_ss");
    	private static LocalDateTime now;
    	private static String perfLogFile;
    	private static FileWriter writer;
    	private static BufferedWriter out;
     
    	public static void InitPerformancesReport(String suffix) {
    		now = LocalDateTime.now();
    		perfLogFile = dtf.format(now) + "_" + suffix + ".log";
    		String directoryName = "C:\\TempsDeResponse";
    		File directory = new File(directoryName);
    		File file = new File(directoryName + "\\" + perfLogFile);
     
    		if (!directory.exists()) {
    			directory.mkdir();
    		}
     
    		try {
    			if (file.createNewFile()) {
    				System.out.println("File is created");
    			}
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot create file");
    			e.printStackTrace();
    		}
     
    		try {
    			writer = new FileWriter(perfLogFile);
    			out = new BufferedWriter(writer);
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot create writer");
    			e.printStackTrace();
    		}
    	}
     
    	public static void WriteToPerformancesReport(String transactionName, Long transactionTime) {
    		try {
     
    			out.write("TEST");
    			out.newLine();
    			System.out.println("Written to file");
     
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			System.out.println("Cannot write to file");
    			e.printStackTrace();
    		}
     
    	}
     
    	public static void ExportPerformancesReport() {
    		try {
    			out.close();
    			writer.close();
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}		
     
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		InitPerformancesReport("EPREMIUM");
    		WriteToPerformancesReport("Test", (long)2000);
    		ExportPerformancesReport();
    	}
    }

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Writing to a text file

    Where does the out instance write to?
    The program is writing a file, but not where you are looking for it.

    Note: Method names should begin with lowercase letters. Class names begin with uppercase.
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: Writing to a text file

    Quote Originally Posted by Norm View Post
    Where does the out instance write to?
    The program is writing a file, but not where you are looking for it.

    Note: Method names should begin with lowercase letters. Class names begin with uppercase.

    Hello,

    Yeah I see. I'm declaring the variable file to hold path + filename but then I'm not using it when I create the writer. Thank you for your help.

    Thanks also for the tip on coding standards, I will review them. Java is definitely not my usual programming language.

    Thank you,
    Muriel

  6. #6
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    Default Re: Writing to a text file

    Thank you. I may have some input. Is this class file part of a package that will perform the function? a copy() method already exist in another file. java.lang.*.

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