设计模式之观察者模式

public class ObserverPattern {public ObserverPattern() {Teacher teacher = new Teacher();Student student = new Student();student.addObserver(teacher);student.exam(80);}/** * 被观察者 */class Student extends Observable {String name = "WCY";int score;void exam(int score) {setScore(score);setChanged();notifyObservers(getScore());}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getScore() {return score;}public void setScore(int score) {this.score = score;}}/** * 观察者 */class Teacher implements Observer {@Overridepublic void update(Observable o, Object arg) {String name = ((Student) o).getName();int score = (int) arg;System.out.println("name:" + name + ",score:" + score);}}}