Use the Registry to store informations (Preferences API)Tag(s): Language


With JDK1.4, the Preferences class can use the Windows registry (on Unix, a file is used) :
import java.util.prefs.Preferences;

public class UsingReg {
  public static final String REALKEY= "com.rgagnon.foo";

  public static void main(String[] args){
     new UsingReg().doit();
  }

  public void doit() {
    // write into HKCU\Software\Javasoft\Prefs\com.rgagnon.foo
    Preferences p = Preferences.userRoot();
    p.put(REALKEY, "bar");

    // read back from HKEY_CURRENT_USER
    System.out.println(p);
    System.out.println(p.get(REALKEY, "HKCU houston we have a problem"));

    // write into HKLM\Software\Javasoft\Prefs\com.rgagnon.foo
    p = Preferences.systemRoot();
    p.put(REALKEY, "barbar");

    // read back from HKEY_LOCAL_MACHINE
    System.out.println(p);
    System.out.println(p.get(REALKEY, "HKLM houston we have a problem"));
  }
}

See also this How-to (Query Windows registry) to access the Windows registry.

With Unix (or Linux), a file is used and you may run into problems if you don't have write access in the default location for the Preferences storage. See this interesting article and these 2 bugs :  1      2    


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