Member Avatar for palavi

I need to write a code in which i want to create each file for every iteration of a loop add data into the file. also the filename should change every time.
for example: familyname1_parts.txt for 1 iteration for second
familyname2.parts.txt for 2 iteration and so on..

try
    	{
    		 out = new FileOutputStream(set.fileLoc + "" +set.fileName,true);
    		
    		p = new PrintStream( out );

here fileloc and set.filename is fetched from a properties file..

earlier all data was added to the same file.

How can we change file name everytime?

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  • Latest Post Latest Post by Linez

Dani AI

Generated

As suggested, the core idea is to change the filename inside the loop. Below is a concise, modern Java pattern (Java 7+) that generates a safe filename from each family name returned by your query, ensures the output directory exists, creates a new file per iteration, and writes to it using try-with-resources so streams are always closed.

import java.nio.file.*;
import java.nio.charset.StandardCharsets;
import java.io.IOException;
import java.io.BufferedWriter;

String family = /* value from query */;
String safe = family.replaceAll("[^A-Za-z0-9._-]", "_");
Path dir = Paths.get(set.fileLoc);
Files.createDirectories(dir);
Path file = dir.resolve(safe + "_part.txt");

try (BufferedWriter w = Files.newBufferedWriter(file, StandardCharsets.UTF_8,
        StandardOpenOption.CREATE_NEW)) {
    w.write("data for " + family);
}

Notes and troubleshooting: use CREATE_NEW to force a fresh file (FileAlreadyExistsException if it exists); use CREATE + TRUNCATEEXISTING to overwrite or CREATE + APPEND to append. Sanitize family names to remove OS-invalid characters and check write permissions on set.fileLoc. If names may repeat, append a counter or timestamp (e.g., safe + "" + counter + ".txt") to avoid collisions. For (C#): same pattern — use Path.Combine, sanitize with Path.GetInvalidFileNameChars, and write inside a using(StreamWriter) block.

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Member Avatar for JamesCherrill

In your loop keep a counter, then make a file name something like this:

String fileName = "familyname" + counter + ".parts.txt2;

Member Avatar for palavi

Hi James,

Thank you very much for responding so soon. I need to accomplish these things in each iteration.

1. create a new file for every iteration.
2. file name should change like this psoc_part.txt , usb_part.txt . i mean technically Sting[abc]_part.txt means this should change dynamically each time.
like this many families are there for each family i need each file to be created along with filename.

i want this code to be in loop to create a new file wenever the family name is matched in which i take it from a query.
sorry for not explaining this in my previous thread.

i will change file name by myself .But i need help on creating creting new file everytime. plz kindly help

FileOutputStream out; 
                PrintStream ps; // declare a print stream object
                try {
                 // Create a new file output stream
                out = new FileOutputStream("myfile.txt");

                        // Connect print stream to the output stream
                        ps = new PrintStream(out);
    
                        ps.println ("This data is written to a file:");
            System.err.println ("Write successfully");
                        ps.close();
                }
Member Avatar for JamesCherrill

What's the problem in creating a new file? You've already got the code:

new FileOutputStream(fileName);

You can do that in your loop if fileName changes on each iteration.

Member Avatar for palavi

Yes, I did it. Thanks a lot.. :-)

Member Avatar for Linez

how would this be done in C#? I was thinking about creating a method for it.

Thanks,
Linez

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