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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
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：
@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：
@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：
@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)
@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：
@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：
@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：
@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。
