java设计模式之:策略模式+工厂模式整合案例实战(一)

本文介绍项目中常用的策略模式+工厂模式的案例，该案例是针对策略类比较少的情况；下一篇会讲解策略类比较多的案例，下面直接开始：

案例1：项目中对系统中的客户和销售进行事件通知(短信、邮件、钉钉)

首先要有通知的策略接口，接口里面要有一个方法就是通知的方法

java 复制代码

public interface PushChannelStrategy｛
   // 通知方法
   SendResult send(MessagePushParam param，BaseMsg baseMsg）;

｝

有了接口那必然有实现类，三个实现类短信、邮件、钉钉

短信：

java 复制代码

@Slf4j
@Component
public class SmsPushChannelStrategy implements PushChannelStrategy｛
   @Autowired
   private NoticeClient noticeClient；
   
   @Override
   public SendResult send（MessagePushParam param，BaseMsg baseMsg）｛
       //1、before send check
       //2、send sms
       NoticeResult noticeResult=noticeClient.sendSms（xxxx）；
       sendResult.setMessageStatus（MessageStatusEnum.SUCCESS）；
       return sendResult；
   ｝
｝

邮件：

java 复制代码

@Slf4j
@Component
public class EmailPushChannelStrategy implements PushChannelStrategy｛
   @Autowired
   private NoticeClient noticeClient；
   
   @Override
   public SendResult send（MessagePushParam param，BaseMsg baseMsg）｛
       //1、before send check
       //2、send email
       Email emailMsg=(Email)baseMsg；
       NoticeResult noticeResult=noticeClient.sendEmail（xxxx）；
       sendResult.setMessageStatus（MessageStatusEnum.SUCCESS）；
       return sendResult；
   ｝
｝

钉钉：

java 复制代码

@Slf4j
@Component
public class DingTalkPushChannelStrategy implements PushChannelStrategy｛
   @Autowired
   private DingTalkClient dingTalkClient；
   
   @Override
   public SendResult send（MessagePushParam param，BaseMsg baseMsg）｛
       //1、before send check
       //2、send ding talk
       SendResult sendResult=dingTalkClient.send(xxx)；
       // 其他结果参数组装
       return sendResult；
   ｝
｝

然后通过策略工厂来获取具体的策略类：(由于只有三个策略类，所以通过注入的方式对channel进行判断)

java 复制代码

@Component
public class PushChannelStrategyFactory｛
    @Autowired 
    private DingTalkPushChannelStrategy dingTalkPushChannelStrategy；
    @Autowired
    private SmsPushChannelStrategy smsPushChannelStrategy；
    @Autowired
    private EmailPushChannelStrategy emailPushChannelStrategy；
    
    public PushChannelStrategy getStrategy(PushChannel pushChannel)｛
        switch(pushChannel)｛
           case DING_TALK：
              return dingTalkPushChannelStrategy；
           case SMS：
              return smsPushChannelStrategy；
           case EMAIL：
              return emailPushChannelStrategy；
           default：
              throw new RuntimeException(＂不支持的类型＂)；
           ｝
     ｝
｝

当然策略工厂针对策略实现类比较少的情况还可以这样写：

java 复制代码

@Component
public class PushChannelStrategyFactory2｛
    @Autowired
    private DingTalkPushChannelStrategy dingTalkPushChannelStrategy;
    @Autowired
    private SmsPushChannelStrategy smsPushChannelStrategy;
    @Autowired
    private EmailPushChannelStrategy emailPushChannelStrategy;
    
    private static final Map<PushChannel,PushChannelStrategy> pushChannelBuilderMap=new HashMap<>();
    
    @PostConstruct
    public void init(){
        pushChannelBuilderMap.put(PushChannel.SMS,smsPushChannelStrategy);
        pushChannelBuilderMap.put(PushChannel.Email,emailPushChannelStrategy);
        pushChannelBuilderMap.put(PushChannel.DING_TALK,dingTalkPushChannelStrategy);
      }

   Public PushChannelStrategy getStrategy(PushChannel PushChannel){
      if(PushChannel==null){
          return null;
       }
       return pushChannelBuilderMap.get(PushChannel);
    }
}

用到的枚举类：

java 复制代码

@Getter
public enum PushChannel{
   SMS(＂sms＂，＂短信＂），
   EMAIL(＂email＂，＂邮件＂），
   DING_TALK(＂dingTalk＂，＂钉钉＂）；
   
   private final String value;
   
   PushChannel(String value,String desc){
      this.value=value;
    }

   public static PushChannel getPushChannel(String pushChannel){
      if(pushChannel==null){
         return null;
      }
      for(PushChannel channel:PushChannel.values()){
        if(pushChannel.equals(channel.getValue())){
           return channel;
       }
   }
    return null;
  }
}

在使用的时候通过策略工厂里面的方法获取具体的策略类：

java 复制代码

@Slf4j
@Service
 public class MessagePushService{
     @Autowired
     private PushChannelStrategyFactory pushChannelStrategyFactory;
     @Autowired
     private MessageRecordRepository messageRecordRepository;
     
     public ResultDTO<Boolean> pushSync(MessagePushCommand command){
        MessagePushParam messagePushParam =MessagePushAssembler.convert(command);
        //1,业务逻辑处理
        //2、根据渠道进行触达
        PushChannel pushChannel=messagePushParam.getChannel();
        if(pushChannel==null){
          throw new MessagePushException(xxx);
        }
        //3、获取具体的策略类
        PushChannelStrategy pushChannelStrategy=pushChannelStrategyFactory.getStrategy(pushChannel);
        SendResult sendResult=PushChannelStrategy.send(messagePushParam,xxx);
        //4,记录落库
        return ResultDTO.getSuccessResult（true）;
    ｝
 ｝

到此该版本的策略模式+工厂模式就结束了，欢迎点评和指出不足之处。