Gets strong-type-value property from a standard Properties : Properties « Collections « Java Tutorial

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import java.util.Properties;
import java.util.Random;

public class StringUtils

   *  Gets an integer-valued property from a standard Properties
   *  list.  If the value does not exist, or is a non-integer, returns defVal.
   *  @since 2.1.48.
   *  @param props The property set to look through
   *  @param key   The key to look for
   *  @param defVal If the property is not found or is a non-integer, returns this value.
   *  @return The property value as an integer (or defVal).
  public static int getIntegerProperty( Properties props,
                                        String key,
                                        int defVal )
      String val = props.getProperty( key );

      return parseIntParameter( val, defVal );

   *  Gets a boolean property from a standard Properties list.
   *  Returns the default value, in case the key has not been set.
   *  The possible values for the property are "true"/"false", "yes"/"no", or
   *  "on"/"off".  Any value not recognized is always defined as "false".
   *  @param props   A list of properties to search.
   *  @param key     The property key.
   *  @param defval  The default value to return.
   *  @return True, if the property "key" was set to "true", "on", or "yes".
   *  @since 2.0.11
  public static boolean getBooleanProperty( Properties props,
                                            String key,
                                            boolean defval )
      String val = props.getProperty( key );

      if( val == null ) return defval;

      return isPositive( val );

   *  Fetches a String property from the set of Properties.  This differs from
   *  Properties.getProperty() in a couple of key respects: First, property value
   *  is trim()med (so no extra whitespace back and front), and well, that's it.
   *  @param props The Properties to search through
   *  @param key   The property key
   *  @param defval A default value to return, if the property does not exist.
   *  @return The property value.
   *  @since 2.1.151
  public static String getStringProperty( Properties props,
                                          String key,
                                          String defval )
      String val = props.getProperty( key );

      if( val == null ) return defval;

      return val.trim();

   *  Returns true, if the string "val" denotes a positive string.  Allowed
   *  values are "yes", "on", and "true".  Comparison is case-insignificant.
   *  Null values are safe.
   *  @param val Value to check.
   *  @return True, if val is "true", "on", or "yes"; otherwise false.
   *  @since 2.0.26
  public static boolean isPositive( String val )
      if( val == null ) return false;

      val = val.trim();

      return val.equalsIgnoreCase("true") || val.equalsIgnoreCase("on") ||

   *  Parses an integer parameter, returning a default value
   *  if the value is null or a non-number.
   *  @param value The value to parse
   *  @param defvalue A default value in case the value is not a number
   *  @return The parsed value (or defvalue).

  public static int parseIntParameter( String value, int defvalue )
      int val = defvalue;

          val = Integer.parseInt( value.trim() );
      catch( Exception e ) {}

      return val;


9.34.1.Setting and Getting Elements
9.34.2.using properties
9.34.3.Getting property by String key value
9.34.4.Getting a key List from Properties
9.34.5.Loading and Saving properties
9.34.6.Use store() to save the properties
9.34.7.List Properties to a print stream or print writer
9.34.8.Using Enumeration to loop through Properties
9.34.9.Put value to a Property list.
9.34.10.Sort Properties when saving
9.34.11.Sorts a property list and turns the sorted list into a string.
9.34.12.Sorts property list and print out each key=value pair prepended with specific indentation.
9.34.13.Load a properties file in the classpath
9.34.14.A Properties file stored in a JAR can be loaded this way
9.34.15.Load a properties file in the startup directory
9.34.16.Have a multi-line value in a properties file
9.34.17.Use XML with Properties
9.34.18.Store properties as XML file
9.34.19.Getting and Setting Properties
9.34.20.Convert a Properties list into a map.
9.34.21.To read a Properties file via an Applet
9.34.22.Read system property as an integer
9.34.23.Read a set of properties from the received input stream, strip off any excess white space that exists in those property values,
9.34.24.Property access utility methods
9.34.25.An utility class to ease up using property-file resource bundles.
9.34.26.Copy a set of properties from one Property to another.
9.34.27.Create Properties from String array
9.34.28.Gets strong-type-value property from a standard Properties
9.34.29.Merge Properties Into Map
9.34.30.Property Loader
9.34.31.Returns a Properties object matching the given node
9.34.32.The properties iterator iterates over a set of enumerated properties.
9.34.33.Use a default property list.