asked on

How to read, insert, update and write a comma seperated text files?

I need some help on the following:

How to read, update and write a comma seperated text file into textarea?

How to sort the text file after insert a new record (if the first five char is the key) and redisplay through JSP?

Thanks.

rrz

Try this. First manually create the file in your web app's root folder.
<%@ page import="java.util.*,java.io.*"%>
<%
File file = new File(application.getRealPath("/text.txt"));
String text = request.getParameter("text");
if(text == null){
char[] data = new char[(int)file.length()];
FileReader fr = new FileReader(file);
int charsRead = fr.read(data);
text = new String(data, 0 , charsRead);
fr.close();
}else{
String[] words = text.split(",");
Arrays.sort(words);
StringBuilder sb = new StringBuilder();
for(int i = 0; i<words.length;i++){
sb.append(words[i] + ",");
}
text = sb.toString();
FileWriter fw = new FileWriter(file);
fw.write(text);
fw.close();
}
%>
<html>
<body>
<form method="post">
<textarea name='text'><%=text%></textarea>
<input Type='submit' value='Submit'/>
</form>
</body>
</html>

gchen91789

ASKER

Thanks for your help. But more question for you,

File file = new File(application.getRealPath("/text.txt"));

I try to change "/text.txt" to "C:" + File.separator + "folder1" + File.separator + "folder2" + File.separator + "text.txt";
I got the application path + file path, How do I point the text.txt to "C:\folder1\folder2\text.txt?

Thanks.

rrz

Did you try ?
File file = new File("C:\\folder1\\folder2\\text.txt"));
or
File file = new File("C:/folder1/folder2/text.txt"));

gchen91789

ASKER

O.K. after I try it, all the data show on the textarea, but it did not separate by line. In addition, how to separate each field with space or tab instead the comma.

Thanks.

ASKER CERTIFIED SOLUTION

rrz

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Mayank S

>> How to sort the text file after insert a new record (if the first five char is the key)

You can load the contents into an ArrayList and then use Collections.sort () - define your own comparator