SpringBoot 策略+工厂模式优化if..else..

男娘i 2023-02-09 10:25 28阅读 0赞

1.策略接口

public interface IStrategy {
    
        /**
         * 根据id获取对应数据
         * @param dispatchQuery
         */
        <T> T getData(QueryParams queryParams);
    }

2. 策略工厂

@Component
    public class StrategyFactory {
        /**
         * 关键功能 Spring 会自动将 EntStrategy 接口的类注入到这个Map中
         */
    
        @Autowired
        private Map<String, IStrategy> strategies = new ConcurrentHashMap<>();
    
        public IStrategy getStrategy(String graphId){
            IStrategy strategy = strategies.get(graphId);
            if(null == strategy) {
                throw new BizException(ResultEnum.STRATEGY_NOT_EXITS);
            }
    
            return strategy;
        }
    }

这里的strategies map用@Autowired修饰， spring IOC会自动将实现Istragety的类put到该map中，这里就是本文的关键，你品，细品！建议看相关源码搞清楚

3.具体的策略类

@Component("one")
    public class OneStrategy implements IStrategy {
     //TODO
    }

这时候的OneStrategy已然在上文中的map中

4.上下文

@Component
    public class DispatchCtx {
    
        @Autowired
        private StrategyFactory strategyFactory;
    
        public <T> T getData(DispatchQuery dispatchQuery) {
            if (StringUtils.isEmpty(dispatchQuery)) {
                throw new BizException(ResultEnum.STRATEGY_NOT_EXITS);
            }
    
            IStrategy strategy = strategyFactory.getStrategy(dispatchQuery.getGraphId());
            return strategy.getGraphData(dispatchQuery);
        }
    
    }

5.替换原来的if...else...

for (String id: graphIds) {
                QueryParams query = QueryParams();
                query .setStrategyId(id);
                Map graphMap = dispatchCtx.getGraphData(query );
                list.add((T) graphMap);
            }

总结：该实现主要运用了java泛型及工厂+策略模式，摆脱了原来的if...else...的逻辑判断的堆砌。

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