\u89c2\u5bdf\u8005\u6a21\u5f0f\u662f\u5178\u578b\u7684\u7528\u6765\u89e3\u8026\u7684\uff0c\u4e00\u4e2a\u88ab\u89c2\u5bdf\u5bf9\u8c61\uff0c\u53ef\u4ee5\u6709\u591a\u4e2a\u89c2\u5bdf\u8005\uff0c\u5bf9\u8c61\u72b6\u6001\u53d8\u5316\uff0c\u81ea\u52a8\u89e6\u53d1\u89c2\u5bdf\u8005\u7684\u901a\u77e5\u884c\u4e3a\u3002<\/p>\n\n\n\n
\u5b9e\u73b0\u65b9\u5f0f\uff1a\n\n1.\u88ab\u89c2\u5bdf\u5bf9\u8c61\n\u9700\u8981\u6709\u4e00\u4e2a\uff08\u591a\u4e2a\uff09\u72b6\u6001\u3001\u9700\u8981\u6709\u4e00\u4e2a\u589e\u52a0\u89c2\u5bdf\u8005\u7684\u529f\u80fd\uff08\u8ba2\u9605\uff09\u3001\u9700\u8981\u4e00\u4e2a\u901a\u77e5\u7684\u65b9\u6cd5\n\n2.\u89c2\u5bdf\u8005\u662f\u4e00\u4e2a\u62bd\u8c61\u7c7b\uff0c\u9700\u8981\u6709\u4e00\u4e2a\u901a\u77e5\u7684\u65b9\u5f0f\n\n3.\u591a\u4e2a\u4e0d\u540c\u7684\u89c2\u5bdf\u8005\u7ee7\u627f\u62bd\u8c61\u7c7b\uff0c\u5b9e\u73b0\u901a\u77e5\u65b9\u6cd5\uff0c\u505a\u4e0d\u540c\u7684\u52a8\u4f5c\n\n4.\u4f8b\u5b50\uff0c\u6765\u81ea\u6587\u672b\u7684\u7b14\u8bb0\n\n\u89c2\u5bdf\u8005\u62bd\u8c61\u7c7b\uff1a\npublic abstract class Observer { \n public abstract void update(String msg);\n}\n\n\u7b2c\u4e00\u4e2a\u89c2\u5bdf\u8005\uff1a\npublic class F_Observer extends Observer {\n public void update(String msg) {\n System.out.println(F_Observer.class.getName() + \" : \" + msg);\n }\n}\n\n\u7b2c\u4e8c\u4e2a\u89c2\u5bdf\u8005\uff1a\npublic class S_Observer extends Observer {\n public void update(String msg) {\n System.out.println(S_Observer.class.getName() + \" : \" + msg);\n }\n}\n\n\u7b2c\u4e09\u4e2a\u89c2\u5bdf\u8005\uff1a\npublic class T_Observer extends Observer {\n public void update(String msg) {\n System.out.println(T_Observer.class.getName() + \" : \" + msg);\n }\n}\n\n\n\u88ab\u89c2\u5bdf\u8005\uff1a\npublic class Subject { \n private List<Observer> observers = new ArrayList<>(); \/\/\u72b6\u6001\u6539\u53d8 \n public void setMsg(String msg) { \n notifyAll(msg); \n } \n \/\/\u8ba2\u9605 \n public void addAttach(Observer observer) { \n observers.add(observer); \n } \n \/\/\u901a\u77e5\u6240\u6709\u8ba2\u9605\u7684\u89c2\u5bdf\u8005 \n private void notifyAll(String msg) { \n for (Observer observer : observers) { \n observer.update(msg); \n } \n }\n}\n\n\u4f7f\u7528\u65b9\u6cd5\uff1a\npublic class Main { \n public static void main(String[] args) { \n F_Observer fObserver = new F_Observer(); \n S_Observer sObserver = new S_Observer(); \n T_Observer tObserver = new T_Observer(); \n Subject subject = new Subject(); \n subject.addAttach(fObserver); \n subject.addAttach(sObserver); \n subject.addAttach(tObserver); \n subject.setMsg(\"msg change\"); \n }\n}\n\n\u8fd0\u884c\u7ed3\u679c\uff1a test.F_Observer : msg changetest.S_Observer : msg changetest.T_Observer : msg change<\/pre>\n\n\n\n