Properties file - keeping comments after modifying the the value

[iyappan sankaran]

i have this proerties file which has two keys (classpath,server). After changing one of the key and store it in a file , i noticed the comments are misssing. How to retain the comments afeter modifying the value.

File.properties
# Server Configuration File

# CLASSPATH - This is the classpath used by the Server
classpath=AdventNetLogging.jar:

# Location of the jserver.properties file
SERVER=myserver

I am setting value like this

_serverProperties.setProperty("classpath","anew.jar");

_serverProperties.store(new FileOutputStream("File.properties
"),null);


pls tell how to solve this one

[Paul Sturrock]

Not an advanced question. Moving...

[Rahul Bhattacharjee]

I think in this way you would loose the comments.You might have to do it with simple file manupulation , if you want to retain the comments.

[Sree Va]

Hi,

My Property file:

base.dir=E:/Test
src=${base.dir}/src
classes=${base.dir}/classes

I am using the following code to read it:

Properties properties = new Properties();
FileInputStream fis = new FileInputStream(propertiesFile);
properties.load(fis);
Enumeration keys = properties.propertyNames();

while (keys.hasMoreElements()) {
String key = (String) keys.nextElement();
String value = properties.getProperty(key);
System.out.println("key:" + key + "-value:" + value);
}


I get the following output:

key:base.dir-value:E:/Test
key:src-value:${base.dir}/src
key:classes-value:${base.dir}/classes


I anticipated

key:base.dir-value:E:/Test
key:src-value:E:/Test/src
key:classes-value:E:/Test/classes

Please help!

Thanks
[ July 11, 2007: Message edited by: Sree Va ]

[Jesper de Jong]

iyappan: The java.util.Properties class was not designed to keep the format of the properties file exactly the same. So
if you load and save your properties file by using the methods in class Properties, the comments and formatting will not be preserved. If this is really important, then you will have to read and write the file yourself (with BufferedReader and FileWriter) and parse and format the properties yourself.

Sree: You are hijacking someone else's topic; please start your own topic next time... To answer your question: So you expected that the Properties class would automatically replace ${...} somehow. It doesn't; that is not functionality of the Properties class. You probably saw this when you were using Ant. Ant is doing this for you; not the java.util.Properties class. So if you need this kind of functionality, you will need to program it yourself: search for ${...} expressions, and replace them by whatever you want.