Properties API and escape charachers

[Hanna Habashy]

hi:
I am using Properties API to write and read the property file. I am have a problem with escape squence '\'. When I write I change '\' to '\\', when I read I lose one '\'. When I write again I loose another '\'.
let me explain:
properties.write("c://sun//java//");
properties.read()
the result: c:/sun/java/ //fine for one time read
if I write the same string again and attempts to read it
the result : c sun java

Do I have to reformat the string every time I read and write,or there is another way?

thanks

[Denis Spirin]

You should use System.getProperty("file.separator"), thats all.

[Willy Leung]

I am a bit confused. There's no read and write methods in the Properties class. According to the API doc, load and store should take care of all the escape characters for you.

[Andy Zhu]

Hey, Hanna:

You may also consider using relative path so that your program is relocatable.

[Hanna Habashy]

hi guys:
Properties.load, and properties.write doesn't take care of this problem for me. I am haveing this proplem becuase, every time I want to wirte a key value pair the the properties file, I have to load the file first, add the key value pair, then rewrite the whole thing to the file.
I tried to just write the new key value pair wiout reloading file, it overrite the file, and it earase everthing there, and leave it with only the new key value pair.
I can't ust relative path all the time. I use it only if the server database file is in the application directory(defualt), but if the application admin chooses to set the server database to anyother file, then it cannot be a relative path.
I hope I made it clearer

[Willy Leung]

Hi Hanna,

I tried to do what you described and couldn't duplicate your problem. Below is the piece of code I wrote. It assumed the properties file already exists. The code reads what's in the file, add one new key-value pair, and writes the file in each iteration.

 
    public static void main(String[] args) {
        try {
            String propFilePath = "C:\\test.properties";
            
            for (int i = 0; i < 10; i++) {
                Properties properties = new Properties();
                
                FileInputStream fis = new FileInputStream(propFilePath);
                properties.load(fis);
                fis.close();
                
                String propKey = "key" + i;
                String propValue = "C:" + System.getProperty("file.separator") + "value" + i;
                properties.put(propKey, propValue);
                                
                FileOutputStream fos = new FileOutputStream(propFilePath);
                properties.store(fos, null);
                fos.close();
            }
            
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }
 

And this is what's in the properties file after running the program.

 
#Mon Jun 07 17:50:45 EDT 2004
key9=C\:\\value9
key8=C\:\\value8
key7=C\:\\value7
key6=C\:\\value6
key5=C\:\\value5
key4=C\:\\value4
key3=C\:\\value3
key2=C\:\\value2
key1=C\:\\value1
key0=C\:\\value0
 

Notice the colons and file separators were all handled automatically.

[Javini Javono]

Hi,


I tried to just write the new key value pair wiout reloading file, it overrite the file,
and it earase everthing there, and leave it with only the new key value pair.


Not speaking to all the details, in general, I believe that I also rewrite the whole
file during the save of the properties even if only one property within the file
has changed.

I don't have any "new" key-value pairs, only a key with perhaps a new value.

Thanks,
Javini Javono