Elangovan Elangovan - 3 months ago 14
Java Question

Updating property value in properties file without deleting other values

Content of

First.properties
:

name=elango
country=india
phone=12345


I want change
country
from
india
to
america
. This is my code:

import java.io.*;
public class UpdateProperty
{
public static void main(String args[]) throws Exception
{
FileOutputStream out = new FileOutputStream("First.properties");
FileInputStream in = new FileInputStream("First.properties");
Properties props = new Properties();
props.load(in);
in.close();
props.setProperty("country", "america");
props.store(out, null);
out.close();
}
}


Output content of
First.properties
:

country=america


The other properties are deleted. I want update a particular property value, without deleting the other properties.

Answer

Open the output stream and store properties after you have closed the input stream.

FileInputStream in = new FileInputStream("First.properties");
Properties props = new Properties();
props.load(in);
in.close();

FileOutputStream out = new FileOutputStream("First.properties");
props.setProperty("country", "america");
props.store(out, null);
out.close();
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