Abastract
public abstract class Forme {
public abstract float perimetre(); //methode abstraite
public abstract float surface(); //methode abstraite
public double rapport() {
return surface() / perimetre();
}
}
Date
Date now = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
System.out.println("Call event " + dateFormat.format(now));
Millisecond to hh:mm:ss
int seconds = (int) (milliseconds / 1000) % 60 ;
int minutes = (int) ((milliseconds / (1000*60)) % 60);
int hours = (int) ((milliseconds / (1000*60*60)) % 24);
String.format("%02d:%02d:%02d", hours, minutes, seconds);
File
Fichier ressource
File file = new File(getClass().getResource("name.txt").getFile());
Fichier temporaire
File temp = File.createTempFile("nom_du_fichier", ".xls");
Parcourir un fichier ligne par ligne
try {
InputStream inputStream = new FileInputStream(new File("readme.txt"));
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String line;
while ((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
bufferedReader.close();
} catch (Exception e) {
System.out.println(e.toString());
}
Trier une liste de fichier par date
List<File> files = new ArrayList<>();
files .add(file1);
files .add(file2);
Collections.sort(files , new Comparator<File>() {
@Override
public int compare(File f1, File f2) {
return Long.valueOf(f1.lastModified()).compareTo(f2.lastModified());
}
});
// The list files is now ordered by dates
Map
Itérer sur un set
HashSet<String> hashSet= new HashSet<String>();
//add elements to HashSet
hashSet.add("fred_1");
hashSet.add("fred_2");
// [...]
hashSet.add("fred_n");
Iterator<String> iterator = hashSet.iterator();
while(iterator.hasNext()){
System.out.println(iterator .next());
}
Map
Itérer sur une map
for (Map.Entry<String, Integer> entry : map.entrySet()) {
System.out.println("Key :"entry.getKey() + " - Value:" + entry.getValue());
}
String
Classe Scanner
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a word :");
String string = scanner.nextLine();
System.out.println("You have entered : " + string);
Thread
public class Counter {
private int step;
private Thread thread;
private Chronometer chronometer;
public void start() {
chronometer = new Chronometer();
thread = new Thread(chronometer);
thread.start();
}
public void stop() {
chronometer.setRunning(false);
}
private class Chronometer implements Runnable {
boolean isRunning;
public Chronometer() {
super();
this.isRunning = true;
}
public boolean isRunning() {
return isRunning;
}
public void setRunning(boolean isRunning) {
this.isRunning = isRunning;
}
public void run() {
do {
step = step + step;
System.out.println("chronometer value :" + step);
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} while (isRunning);
System.out.println("thread chronometer will stop");
}
}
}