这是使用工厂的策略模式的示例：
public interface Strategy { public Object[] execute(Object[] args);}public class StrategyFactory { public enum Name { REVERSE, STRINGIFY, DUPLICATE; } private StrategyFactory() { // never instantiate; only use static factory methods } public static Strategy getStrategyReverse() { return new Strategy() { public Object[] execute(Object[] args) { Object[] reversed = new Object[args.length]; for (int i = 0; i < args.length; i++) { reversed[i] = args[args.length - i - 1]; } return reversed; } }; } public static Strategy getStrategyStringify() { return new Strategy() { public Object[] execute(Object[] args) { String[] stringified = new String[args.length]; for (int i = 0; i < args.length; i++) { stringified[i] = String.valueOf(args[i]); } return stringified; } }; } public static Strategy getStrategyDuplicate() { return new Strategy() { public Object[] execute(Object[] args) { Object[] duplicated = new Object[2 * args.length]; for (int i = 0; i < args.length; i++) { duplicated[i * 2] = args[i]; duplicated[i * 2 + 1] = args[i]; } return duplicated; } }; } public static Strategy getStrategy(String name) { return getStrategy(Name.valueOf(name)); } public static Strategy getStrategy(Name name) { switch (name) { case REVERSE: return getStrategyReverse(); case STRINGIFY: return getStrategyStringify(); case DUPLICATE: return getStrategyDuplicate(); default: throw new IllegalStateException("No strategy known with name " + name); } }}public class Main { public static void main(String[] args) { Strategy strategy = StrategyFactory.getStrategy("DUPLICATE"); System.out.println(Arrays.toString(strategy.execute(args))); }}
