Java by API/java.util/Properties

new Properties()

  
/*
 * Output:
 * 
a 1
A 2
c: 3
z: default
 *  
 */
import java.util.Properties;
public class MainClass {
    public static void main(String args[]) {
        Properties prop = new Properties();
        prop.put("a", "1");
        prop.put("b", "2");
        prop.put("c", "3");
        Properties book = new Properties(prop);
        book.put("A", "4");
        book.put("B", "5");
        
        System.out.println("a " + book.getProperty("a"));
        System.out.println("A " + book.getProperty("b"));
        System.out.println("c: " + book.getProperty("c"));
        System.out.println("z: " + book.getProperty("z", "default"));
    }
}

new Properties(Properties prop)

  
/*
 * Output:
 * 
a 1
A 2
c: 3
z: default
 *  
 */
import java.util.Properties;
public class MainClass {
    public static void main(String args[]) {
        Properties prop = new Properties();
        prop.put("a", "1");
        prop.put("b", "2");
        prop.put("c", "3");
        Properties book = new Properties(prop);
        book.put("A", "4");
        book.put("B", "5");
        
        System.out.println("a " + book.getProperty("a"));
        System.out.println("A " + book.getProperty("b"));
        System.out.println("c: " + book.getProperty("c"));
        System.out.println("z: " + book.getProperty("z", "default"));
    }
}

Properties: getProperty(String key)

  
/*
 * Output:
 * 
a 1
A 2
c: 3
z: default
 *  
 */
import java.util.Properties;
public class MainClass {
    public static void main(String args[]) {
        Properties prop = new Properties();
        prop.put("a", "1");
        prop.put("b", "2");
        prop.put("c", "3");
        Properties book = new Properties(prop);
        book.put("A", "4");
        book.put("B", "5");
        
        System.out.println("a " + book.getProperty("a"));
        System.out.println("A " + book.getProperty("b"));
        System.out.println("c: " + book.getProperty("c"));
        System.out.println("z: " + book.getProperty("z", "default"));
    }
}

Properties: getProperty(String key, String defaultValue)

  
/*
 * Output:
 * 
a 1
A 2
c: 3
z: default
 *  
 */
import java.util.Properties;
public class MainClass {
    public static void main(String args[]) {
        Properties prop = new Properties();
        prop.put("a", "1");
        prop.put("b", "2");
        prop.put("c", "3");
        Properties book = new Properties(prop);
        book.put("A", "4");
        book.put("B", "5");
        
        System.out.println("a " + book.getProperty("a"));
        System.out.println("A " + book.getProperty("b"));
        System.out.println("c: " + book.getProperty("c"));
        System.out.println("z: " + book.getProperty("z", "default"));
    }
}

Properties: keySet()

  
/**
 *Output:
 The value of K2 is V2.
The value of K1 is V1.
 */
import java.util.Properties;
import java.util.Set;
public class MainClass {
  public static void main(String args[]) {
    Properties capitals = new Properties();
    capitals.put("K1", "V1");
    capitals.put("K2", "V2");
    Set states = capitals.keySet();
    for (Object name : states)
      System.out.println("The value of " + name + " is "
          + capitals.getProperty((String) name) + ".");
  }
}

Properties: list(PrintStream out)

  
/*
 * Output:
-- listing properties --
java.runtime.name=Java(TM) 2 Runtime Environment, Stand...
java.vm.version=1.5.0-b64
java.vm.vendor=Sun Microsystems Inc.
java.vendor.url=http://java.sun.ru/
path.separator=;
java.vm.name=Java HotSpot(TM) Client VM
file.encoding.pkg=sun.io
user.country=US
sun.os.patch.level=Service Pack 2
java.vm.specification.name=Java Virtual Machine Specification
java.runtime.version=1.5.0-b64
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
...
...
 */
import java.util.Properties;
public class MainClass {
  public static void main(String[] args) {
    Properties properties = System.getProperties();
    properties.list(System.out);
  }
}

Properties: loadFromXML(InputStream in)

 
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Date;
import java.util.Properties;
public class Main {
  public static void main(String args[]) throws Exception {
    Properties p = new Properties();
    p.put("today", new Date().toString());
    p.put("user", "A");
    FileOutputStream out = new FileOutputStream("user.props");
    p.storeToXML(out, "updated");
    FileInputStream in = new FileInputStream("user.props");
    p.loadFromXML(in);
    p.list(System.out);
  }
}

Properties: load(InputStream inStream)

  
import java.io.FileInputStream;
import java.util.Properties;
public class MainClass {
  public static void main(String args[]) throws Exception {
    Properties p = new Properties();
    p.load(new FileInputStream("colon.txt"));
    p.list(System.out);
  }
}
//File: colon.txt
/*
foo:bar
one
two
three=four
five  six seven eight
nine ten
*/

Properties: propertyNames()

  
import java.awt.EventQueue;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.util.Arrays;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Properties;
import java.util.SortedSet;
import java.util.TreeSet;
import javax.swing.AbstractListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.ToolTipManager;
public class MainClass extends JList {
  SortedListModel model;
  Properties tipProps;
  public MainClass(Properties props) {
    model = new SortedListModel();
    setModel(model);
    ToolTipManager.sharedInstance().registerComponent(this);
    tipProps = props;
    addProperties(props);
  }
  private void addProperties(Properties props) {
    Enumeration names = props.propertyNames();
    while (names.hasMoreElements()) {
      model.add(names.nextElement());
    }
  }
  public String getToolTipText(MouseEvent event) {
    Point p = event.getPoint();
    int location = locationToIndex(p);
    String key = (String) model.getElementAt(location);
    String tip = tipProps.getProperty(key);
    return tip;
  }
  public static void main(String args[]) {
    JFrame frame = new JFrame("Custom Tip Demo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Properties props = System.getProperties();
    MainClass list = new MainClass(props);
    JScrollPane scrollPane = new JScrollPane(list);
    frame.add(scrollPane);
    frame.setSize(300, 300);
    frame.setVisible(true);
  }
}
class SortedListModel extends AbstractListModel {
  SortedSet<Object> model;
  public SortedListModel() {
    model = new TreeSet<Object>();
  }
  public int getSize() {
    return model.size();
  }
  public Object getElementAt(int index) {
    return model.toArray()[index];
  }
  public void add(Object element) {
    if (model.add(element)) {
      fireContentsChanged(this, 0, getSize());
    }
  }
  public void addAll(Object elements[]) {
    Collection<Object> c = Arrays.asList(elements);
    model.addAll(c);
    fireContentsChanged(this, 0, getSize());
  }
  public void clear() {
    model.clear();
    fireContentsChanged(this, 0, getSize());
  }
  public boolean contains(Object element) {
    return model.contains(element);
  }
  public Object firstElement() {
    return model.first();
  }
  public Iterator iterator() {
    return model.iterator();
  }
  public Object lastElement() {
    return model.last();
  }
  public boolean removeElement(Object element) {
    boolean removed = model.remove(element);
    if (removed) {
      fireContentsChanged(this, 0, getSize());
    }
    return removed;
  }
}

Properties: setProperty(String key, String value)

 

import java.io.FileOutputStream;
import java.util.Properties;
public class Main {
  public static void main(String[] args) throws Exception {
    Properties properties = new Properties();
    properties.setProperty("database.type", "mysql");
    properties.setProperty("database.url", "jdbc:mysql://localhost/mydb");
    properties.setProperty("database.username", "root");
    properties.setProperty("database.password", "root");
    FileOutputStream fos = new FileOutputStream("database-configuration.xml");
    properties.storeToXML(fos, "Database Configuration", "UTF-8");
  }
}

Properties: store(OutputStream out, String comments)

  

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Properties;
public class Main {
  public static void main(String args[]) throws Exception {
    Properties p = new Properties();
    p.load(new FileInputStream("test.txt"));
    p.store(new FileOutputStream("t.txt"),"no comments");
  }
}

Properties: storeToXML(OutputStream os, String comment)

 
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Date;
import java.util.Properties;
public class Main {
  public static void main(String args[]) throws Exception {
    Properties p = new Properties();
    p.put("today", new Date().toString());
    p.put("user", "A");
    FileOutputStream out = new FileOutputStream("user.props");
    p.storeToXML(out, "updated");
    FileInputStream in = new FileInputStream("user.props");
    p.loadFromXML(in);
    p.list(System.out);
  }
}