Replace Text

[Mudit Srivastava]

Hi All,

I have a text file which contains the following content

ABC=true
XYZ=true
DEF=false

I want to read from this file and check the property XYZ. If found true, I must replace with false. I am now unsure of how to delete the existing "true" value of XYZ from the file.

My current approach is as follows:

File file = new File("test.txt");
		BufferedWriter bw = new BufferedWriter(new FileWriter(file));
		bw.write("ABC=true");
		bw.newLine();
		bw.write("XYZ=true");
		bw.newLine();
		bw.write("DEF=true");
		bw.flush();
		
		BufferedReader br = new BufferedReader(new FileReader(file));
		String s = null;
		ArrayList<String> list = new ArrayList<String>();
		while((s=br.readLine())!=null)
		{

			System.out.println(s);
			if(s.contains("XYZ") && s.endsWith("true"))
			{
				System.out.println("Inside If");
				s=s.replace("true", "false");
			}
			list.add(s);
			continue;
		}
		PrintWriter pw = new PrintWriter(file); //this seems unnecessary.  
	
		BufferedWriter bw2 = new BufferedWriter(new FileWriter(file));

		for(String s2:list)
		{
			bw2.append(s2);
			bw2.newLine();
		}
		bw2.flush();
		//close writers/reader	    

Kindly help since i have to create the entire file again using the ArrayList after clearing the entire content

[Balu Sadhasivam]

Mudit,

If your file is in format of key-value pair , you can use Properties API to acheive this.Note that Properties requires your file to be with .properties extn.

Use setProperty() method to change the proprty you want and then use Properties save method( on same loaded properties object) to save the properties to a file.

HTH

[Mudit Srivastava]

Thanks for the post Balu.

Trouble is that I'm stuck with the .txt extension so I can't switch to the Properties API.

[Ulf Dittmer]

The Properties class doesn't care about the file extension - it can be anything you want.

[Balu Sadhasivam]

The Properties class doesn't care about the file extension - it can be anything you want.

yes , Thanks for the correction.

[Mudit Srivastava]

Thanks guys. The Properties API worked like a charm..