Java properties files: direct access to an element

samuele.mattiuzzo · 2010-08-19 16:09:33

Hello,

i have to deal with java properties files. Actually i have a file called prop.properties and it's structured like this

index1=1
name1=asd
index2=2
name2=rotfl
val2=10

which suits my needs. To read values i have a loop from 0 to 10, which i use to read "<key_name>+<index>" from properties (example: at loop 0, index = 0, so i'm searching for "index0","name0" and so on).
As i understood, this means my script everytime loops through the whole file to find the correct key, and i was thinking if maybe there was a quick way to direct access every element, instead of reading all n-1 elements before the nth i need, but googling around still didn't help me do you have any hint for me?
thanks!

Inxsible · 2010-08-19 16:11:14

Looping through properties file is a bad idea. You can do something like this.

System.getProperty("propertyname");

Or if all your properties relate to a particular module that you have in your code, you can even create a custom Properties object

samuele.mattiuzzo · 2010-08-19 16:13:08

that's what i'm using now, but my teacher told me it looks for every other element before that one, instead of doing a direct access to that element... or is that wrong?

Inxsible · 2010-08-19 16:15:41

http://download.oracle.com/javase/1.4.2 … ng.String)

Hmm I am not entirely sure about the inner workings of the System.getProperty() call.

But if you want you can always create a Map of all the properties and then use that in place of a properties file.

EDIT : The more I think about it, I am sure the getProperty also uses a hashtable behind the scenes. It would be wasteful to use a list for properties file which is nothing but a key-value pair

Last edited by Inxsible (2010-08-19 16:18:23)

samuele.mattiuzzo · 2010-08-19 16:21:37

reading your reply gave me the correct input of search and i went looking for this:

java.util
Class Properties

java.lang.Object
  extended byjava.util.Dictionary
      extended byjava.util.Hashtable
          extended byjava.util.Properties

All Implemented Interfaces:
    Cloneable, Map, Serializable

so i guess it uses a map or an hashtable to do the search, and the getProperty() call does what i need

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#1 2010-08-19 16:09:33

Java properties files: direct access to an element

#2 2010-08-19 16:11:14

Re: Java properties files: direct access to an element

#3 2010-08-19 16:13:08

Re: Java properties files: direct access to an element

#4 2010-08-19 16:15:41

Re: Java properties files: direct access to an element

#5 2010-08-19 16:21:37

Re: Java properties files: direct access to an element

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