How to get list of properties using apache.commons

Question

I need to get the list of properties which are in the .properties file. For example, if have the following .properties file:

users.admin.keywords = admin
users.a         


        

Answer 1

You can use as below:

Configuration configuration = new PropertiesConfiguration(filename);
Iterator<String> keys = configuration.getKeys();
List<String> keyList = new ArrayList<String>();
while(keys.hasNext()) {
    keyList.add(keys.next());
}

Answer 2

You can use getKeys().

It returns an Iterator<String> on all the keys in the properties file.

Answer 3

Properties prop = new Properties();
prop.load(new FileInputStream("prop.properties"));
Set<Map.Entry<Object, Object>> set = prop.entrySet();
List<Object> list = new ArrayList<>();
for (Map.Entry<Object, Object> entry : prop.entrySet())
{
   list.add(entry.getKey());
}
System.out.println(list);

Using Apache Commons version <2.1:

Configuration config = new PropertiesConfiguration("prop.properties");
List<String> list = new ArrayList<>();
Iterator<String> keys = config.getKeys();
while(keys.hasNext()){
    String key = (String) keys.next();
    list.add(key);
}

Edited for Apache Commons Version 2.1:

List<String> list = new ArrayList<>();
Parameters params = new Parameters();
FileBasedConfigurationBuilder<FileBasedConfiguration> builder =
    new FileBasedConfigurationBuilder<FileBasedConfiguration>
    (PropertiesConfiguration.class)
    .configure(params.properties()
    .setFileName("prop.properties"));
try
{
    Configuration config = builder.getConfiguration();
    Iterator<String> keys = config.getKeys();
    while(keys.hasNext()){
      String key = (String) keys.next();
      list.add(key);
    }
}
catch(ConfigurationException cex)
{
    // handle exception here
}