如何优雅的替换掉Java代码中的if else

public class SmsSendService{
	/**
 	 * @Param phoneNo 手机号
	 * @Param content 短信内容
	 */
	public void send(String phoneNo,String content){
		//从配置中读取 短信渠道
		String channelType=config.getChannelType();
		
		//如果是短信渠道A，则调用渠道A的api发送
		if(Objects.equals(channelType,"CHANNEL_A")){
			System.out.println("通过短信渠道A发送短信");
		}
		//如果是短信渠道B，则调用渠道B的api发送
		else if(Objects.equals(channelType,"CHANNEL_B")){
			System.out.println("通过短信渠道B发送短信");
		}
	}
}

//... 此处省略部分代码 ...

//从配置中读取 短信渠道
String channelType=config.getChannelType();
//如果是短信渠道A，则调用渠道A的api发送
if(Objects.equals(channelType,"CHANNEL_A")){
	System.out.println("通过短信渠道A发送短信");
}
//如果是短信渠道B，则调用渠道B的api发送
else if(Objects.equals(channelType,"CHANNEL_B")){
	System.out.println("通过短信渠道B发送短信");
}
//ADD: 如果是短信渠道C，则调用渠道C的api发送
else if(Objects.equals(channelType,"CHANNEL_C")){
	System.out.println("通过短信渠道C发送短信");
}

//... 此处省略部分代码 ...

public interface SmsChannelService{
	//发送短信
	void send(String phoneNo,String content);
}

public class SmsChannelServiceImplA implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道A发送短信");
	}
}

public class SmsChannelServiceImplB implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道B发送短信");
	}
}

public class SmsChannelFactory {
	private Map<String,SmsChannelService> serviceMap;

	//初始化工厂，将所有的短信渠道Service放入Map中
	public SmsChannelFactory(){
		//渠道类型为 key , 对应的服务类为value ：
		serviceMap=new HashMap<String, SmsChannelService>(2);
		serviceMap.put("CHANNEL_A",new SmsChannelServiceImplA());
		serviceMap.put("CHANNEL_B",new SmsChannelServiceImplB());
	}

	//根据短信渠道类型获得对应渠道的Service
	public SmsChannelService buildService(String channelType){
		return serviceMap.get(channelType);
	}
}

public class SmsSendService {

	private SmsChannelFactory smsChannelFactory;

	public SmsSendService(){
		smsChannelFactory=new SmsChannelFactory();
	}

	public void send(String phoneNo,String content){
		//从配置中读取 短信渠道
		String channelType=config.getChannelType();
		//获取渠道类型对应的服务类
		SmsChannelService channelService=smsChannelFactory.buildService(channelType);
		//发送短信
		channelService.send(phoneNo,content);
	}

}

public class SmsChannelServiceImplC implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道C发送短信");
	}
}

public class SmsChannelFactory {
	private Map<String,SmsChannelService> serviceMap;

	//初始化 serviceMap ，将所有的短信渠道Service放入Map中
	public SmsChannelFactory(){
		//渠道类型为 key , 对应的服务类为value ：
		serviceMap=new HashMap<String, SmsChannelService>(3);
		serviceMap.put("CHANNEL_A",new SmsChannelServiceImplA());
		serviceMap.put("CHANNEL_B",new SmsChannelServiceImplB());
		//ADD 增加一行 SmsChannelServiceImplC 的初始化代码 
		serviceMap.put("CHANNEL_C",new SmsChannelServiceImplC());
	}

	//根据渠道类型构建短信渠道Service
	public SmsChannelService buildService(String channelType){
		return serviceMap.get(channelType);
	}
}

public interface SmsChannelService {
	//发送短信
	void send(String phoneNo,String content);
	//关键：增加getChannelType()方法，子类实现这个方法用于标识出渠道类型
	String getChannelType();
}

@Service
public class SmsChannelServiceImplA implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道A发送短信");
	}
	//关键：增加 getChannelType() 实现
	public String getChannelType() {
		return "CHANNEL_A";
	}
}

@Service
public class SmsChannelServiceImplB implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道B发送短信");
	}
	//关键：增加 getChannelType() 实现
	public String getChannelType() {
		return "CHANNEL_B";
	}
}

@Service
public class SmsChannelFactory {

	private Map<String,SmsChannelService> serviceMap;
	
	/*注入：通过spring容器将所有实现 SmsChannelService 接口的类的实例注入到 serviceList 中*/
	@Autowired
	private List<SmsChannelService> serviceList;

	/*通过 @PostConstruct 注解，在 SmsChannelFactory 实例化后，来初始化 serviceMap */
	@PostConstruct
	private void init(){
		if(CollectionUtils.isEmpty(serviceList)){
			return ;
		}
		serviceMap=new HashMap<String, SmsChannelService>(serviceList.size());
		//将 serviceList 转换为 serviceMap
		for (SmsChannelService channelService : serviceList) {
			String channelType=channelService.getChannelType();
			//重复性校验，避免不同实现类的 getChannelType() 方法返回同一个值。
			if(serviceMap.get(channelType)!=null){
				throw new RuntimeException("同一个短信渠道只能有一个实现类");
			}
			/*渠道类型为 key , 对应的服务类为value ：
			与“优化代码1”中的通过手工设置“CHANNEL_A"、"CHANNEL_B"相比，
			这种方式更加自动化，后续在增加“CHANNEL_C"无需再改此处代码*/
			serviceMap.put(channelType,channelService);
		}
	}

	//根据渠道类型获取对应短信渠道的Service
	public SmsChannelService buildService(String channelType){
		return serviceMap.get(channelType);
	}
}

@Service
public class SmsSendService {

	@Autowired
	private SmsChannelFactory smsChannelFactory;

	public void send(String phoneNo,String content){
		//从配置中读取短信渠道类型
		String channelType=config.getChannelType();
		//构建渠道类型对应的服务类
		SmsChannelService channelService=smsChannelFactory.buildService(channelType);
		//发送短信
		channelService.send(phoneNo,content);
	}

}

@Service
public class SmsChannelServiceImplC implements SmsChannelService {
	public void send(String phoneNo, String content) {
		System.out.println("通过短信渠道C发送短信");
	}

	public String getChannelType() {
		return "CHANNEL_C";
	}
}