java策略模式三种实现方案

方案1：@Autowired Map

public interface ClientService {void hanlde(Object obj);String type();
}

@Service
public class PcClientService implements ClientService  {    @Overridepublic void handle(Object obj) {// todo pc客户端逻辑}    @Overridepublic String type() {// 使用时根据type匹配对应实现类，可以使用枚举或常量代替return "pcClientService ";}
}

@Service
public class AndroidClientService implements ClientService  {    @Overridepublic void handle(Object obj) {// todo Android客户端逻辑}    @Overridepublic String type() {// 使用时根据type匹配对应实现类（对应beanname），可以使用枚举或常量代替return "androidClientService ";}
}

    @Autowiredprivate Map<String, ClientService> clientHandlers;// 策略调用public void strategy(String strategyType) {clientHandlers.get(strategyType).handle();}

方案2： @PostConstruct

public interface ClientService {void hanlde(Object obj);
}

public class ClientManager {private static final Map<String, ClientService> clientHandlers = new ConcurrentHashMap<>();public static void register(String type, ClientService service) {clientHandlers.put(type, service);}
}


@Component
public class PcClientServiceImpl implements ClientService{@PostConstructpublic void afterInit() {// 不需要 type() 方法了// 但我们仍需要在注册策略时提供 type 参数ClientManager.register("pcClientServiceImpl ", this);}// 使用方式同上
}

方案三：InitializingBean
相比第二种@PostConstruct增加了约束力，避免忘记实现@PostConstruct方法

public interface ClientService extends InitializingBean {void hanlde(Object obj);
}

public class PcClientServiceImpl implements ClientService {@Overridepublic void hanlde(Object obj) {// todo 业务逻辑}@Overridepublic void afterPropertiesSet() throws Exception {    ClientManager.register("pcClientServiceImpl ", this);}
}