职责链模式实际应用

我就是我 2022-10-13 01:52 104阅读 0赞

### 需求背景 ###

需 求 ： 根 据 各 种 规 则 过 滤 数 据 ， 筛 选 出 满 足 条 件 的 数 据 \\color\{red\} 需求：根据各种规则过滤数据，筛选出满足条件的数据 需求：根据各种规则过滤数据，筛选出满足条件的数据  
要求：  
1. 支持各种规则动态组合  
2. 尽量灵活搭配，不要指定某种情景下的过滤器

### 代码下载 ###

[源代码下载][Link 1]

### 职责链模式 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aGVnYWE_size_16_color_FFFFFF_t_70]

### 开发设计 ###

1.  定义规则过滤器顶级接口

package com.dgut.edu.com.filterproject.filterchain.filter;
    
    /**
     * FileName: Filter
     * Author:
     * Date:     2021/6/22 19:09
     * Description: 过滤器接口
     */
    public interface RuleFilter<T> {
    
    	/**
    	 * 口径过滤逻辑
    	 * @param entity
    	 * @return true表示可以执行下一个过滤器,false终止过滤
    	 */
    	boolean filter(T entity)throws Exception;
    
    	/**
    	 * 获取器的名称
    	 * @return
    	 */
    	String name();
    }

1.1 具体实现类

package com.dgut.edu.com.filterproject.filterchain.filter.impl;
    
    import com.dgut.edu.com.filterproject.entity.PriceCompareResult;
    
    import com.dgut.edu.com.filterproject.filterchain.filter.RuleFilter;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.stereotype.Component;
    
    /**
     * @description: 跟价口径中，商品属性过滤器，过滤掉不满足条件的数据
     * @author: hongbin.zheng
     * @create: 2021-06-28 14:39
     **/
    @Slf4j
    @Component
    public class MerchandiseRuleFilter implements RuleFilter<PriceCompareResult> {
        
    
        private static final String MERCHANDISE_RULE_FILTER_NAME = "商品属性过滤器";
    
        /**
         * 1. 商品名称包含套装
         *
         * @param entity
         * @return
         * @throws Exception
         */
        @Override
        public boolean filter(PriceCompareResult entity) throws Exception {
        
            // 1. 过滤内网无货商品、过滤分货、过滤库存、过滤下架商品状态
            if (entity == null) {
        
                return true;
            }
    
            if (entity.getGoodsName().contains("套装")) {
        
                return true;
            }
            return false;
    
    
        }
    
    
        @Override
        public String name() {
        
            return "merchandiseRuleFilter";
        }
    }

package com.dgut.edu.com.filterproject.filterchain.filter.impl;
    
    import com.dgut.edu.com.filterproject.entity.PriceCompareResult;
    import com.dgut.edu.com.filterproject.filterchain.filter.RuleFilter;
    
    import com.dgut.edu.com.filterproject.utils.RuleFilterUtils;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.stereotype.Component;
    
    /**
     * @description: 专场过滤器
     * @author: hongbin.zheng
     * @create: 2021-06-28 17:24
     **/
    @Slf4j
    @Component
    public class SalesNoRuleFilter implements RuleFilter<PriceCompareResult> {
        
        private static final String SALES_NAME_RULE_FILTER_NAME = "商品专场过滤器";
    
        /**
         * 2. 专场包含：专场包含VIP 和 LUX (顺序先后无关系了)
         *
         * @param entity
         * @return
         * @throws Exception
         */
        @Override
        public boolean filter(PriceCompareResult entity) throws Exception {
        
            // 1 专场包含VIP 和 LUX (顺序先后无关系了)
            if (RuleFilterUtils.containsWord(entity.getSalesName(), RuleFilterUtils.VIP) &&
                    RuleFilterUtils.containsWord(entity.getSalesName(), RuleFilterUtils.LUX)) {
        
                return true;
            }
            return false;
        }
    
        @Override
        public String name() {
        
            return "salesNoRuleFilter";
        }
    }

2、BusinessHandler

package com.dgut.edu.com.filterproject.filterchain.handler;
    
    /**
     * FileName: Handler
     * Author:
     * Date:     2021/6/22 19:12
     * Description: 业务处理接口
     */
    public interface BusinessHandler<T> {
        
    
    
    	/**
    	 * 处理方法
    	 * @param entity
    	 */
    	void handler(T entity);
    
    }

3、FilterChainConfig 过滤器配置

package com.dgut.edu.com.filterproject.filterchain;
    
    import lombok.Data;
    
    import java.util.List;
    
    /**
     * FileName: FilterChainConfig
     * Author:   shangjie.tang
     * Date:     2021/6/22 20:08
     * Description: 解析配置
     */
    @Data
    public class FilterChainConfig {
        
    
    	private String name;
    	private String handler;
    	private Boolean enable;
    	private List<String> filterList;
    
    }

4、 FilterChainFactory 过滤链创建工厂

package com.dgut.edu.com.filterproject.filterchain;
    
    import com.dgut.edu.com.filterproject.filterchain.filter.RuleFilter;
    import com.dgut.edu.com.filterproject.filterchain.handler.BusinessHandler;
    import com.google.common.collect.Maps;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.ApplicationContext;
    import org.springframework.stereotype.Service;
    
    import javax.annotation.PostConstruct;
    import java.util.Map;
    import java.util.Optional;
    
    /**
     * FileName: FilterChainF
     * Author:   shangjie.tang
     * Date:     2021/6/22 20:06
     * Description: 根据配置,创建过滤链的工厂
     */
    @Service
    @Slf4j
    public class FilterChainFactory {
        
    
    	@Autowired
    	private ApplicationContext context;
    
    	private Map<String, RuleFilter> filterMap;
    
    	private Map<String, BusinessHandler> handlerMap;
    
    
    	@PostConstruct
    	private void init(){
        
    		filterMap = Maps.newHashMap();
    		handlerMap = Maps.newHashMap();
    		Map<String, RuleFilter> filterBeanMap = context.getBeansOfType(RuleFilter.class);
    		for (Map.Entry<String, RuleFilter> entry : filterBeanMap.entrySet()) {
        
    			filterMap.put(entry.getValue().name(),entry.getValue());
    		}
    		Map<String, BusinessHandler> handlerBeanMap = context.getBeansOfType(BusinessHandler.class);
    		for (Map.Entry<String, BusinessHandler> entry : handlerBeanMap.entrySet()) {
        
    			handlerMap.put(entry.getKey(),entry.getValue());
    		}
    	}
    
    
    	public <T> FilterChain<T> createChains(FilterChainConfig config,Class<T> tClass){
        
    		FilterChain<T> chain = new FilterChain<T>(config.getName(),handlerMap.get(config.getHandler()), Optional.ofNullable(config.getEnable()).orElse(true));
    		for (String filterBeanName : config.getFilterList()) {
        
    			RuleFilter<T> filter = filterMap.get(filterBeanName);
    			if(filter!=null){
        
    				chain.addFilter(filter);
    			}
    		}
    		log.info("创建过滤链成功");
    		return chain;
    	}
    
    }

5、过滤链 FilterChain

package com.dgut.edu.com.filterproject.filterchain;
    
    
    import com.dgut.edu.com.filterproject.filterchain.filter.RuleFilter;
    import com.dgut.edu.com.filterproject.filterchain.handler.BusinessHandler;
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.ArrayList;
    import java.util.List;
    
    
    /**
     * FileName: BaseFilterChain
     * Author:   shangjie.tang
     * Date:     2021/6/22 19:11
     * Description: 过滤链
     */
    @Slf4j
    public class FilterChain<T> {
        
    
        private String name;
        private BusinessHandler<T> businessHandler;
        private List<RuleFilter<T>> chain;
        private boolean enable;
    
        public FilterChain(String name, BusinessHandler<T> businessHandler, boolean enable) {
        
            this.name = name;
            this.businessHandler = businessHandler;
            this.enable = enable;
            this.chain = new ArrayList<>();
        }
    
        public void addFilter(RuleFilter<T> ruleFilter) {
        
            this.chain.add(ruleFilter);
        }
    
        /**
         * 开始进行过滤
         *
         * @param entity
         * @return 通过返回原样, 不通过返回null
         * @throws Exception
         */
        public T process(T entity) throws Exception {
        
            if (enable && chain.size() != 0) {
        
                for (RuleFilter<T> ruleFilter : chain) {
        
                    if (ruleFilter.filter(entity)) {
        
                        log.info("FilterChain_process-filter","没有通过该过滤器");
                        return null;
                    }
                }
                //能达到这步的,都是符合业务的数据,执行业务操作
                if (businessHandler != null) {
        
                    businessHandler.handler(entity);
                }
            } else {
        
                log.info("FilterChain_process-filterChain_name","过滤链没有启用");
            }
            return entity;
        }
    
        public String getName() {
        
            return name;
        }
    }

6、读取配置 CfgCenterUtil

package com.dgut.edu.com.filterproject.service;
    
    public class CfgCenterUtil {
        
        public static String getValue(String CfgName, String other) {
        
            return "[\n" +
                    "\t{\n" +
                    "\t\t\"name\":\"过滤链\",\n" +
                    "\t\t\"handler\":\"\",\n" +
                    "\t\t\"filterList\":[\"merchandiseRuleFilter\", \"salesNoRuleFilter\"]\n" +
                    "\t}\n" +
                    "\t\n" +
                    "]";
        }
    }

7、包装服务层

package com.dgut.edu.com.filterproject.service;
    
    import com.alibaba.fastjson.JSONArray;
    import com.dgut.edu.com.filterproject.entity.PriceCompareResult;
    import com.dgut.edu.com.filterproject.filterchain.FilterChain;
    import com.dgut.edu.com.filterproject.filterchain.FilterChainConfig;
    import com.dgut.edu.com.filterproject.filterchain.FilterChainFactory;
    import com.google.common.collect.Lists;
    import lombok.extern.slf4j.Slf4j;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.util.DigestUtils;
    import org.springframework.util.StringUtils;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.stream.Collectors;
    
    @Service
    @Slf4j
    public class PcResultFilterService {
        
        @Autowired
        private FilterChainFactory filterChainFactory;
    
        /**
         * 老配置的md5
         */
        private String oldConfigMd5;
    
        /**
         * 生成的过滤链
         */
        private List<FilterChain<PriceCompareResult>> filterChains = new ArrayList<>();
    
        /**
         * 批量进行过滤
         *
         * @param priceCompareResultList
         * @return
         */
        public List<PriceCompareResult> batchExecute(List<PriceCompareResult> priceCompareResultList) {
        
            return priceCompareResultList.stream().filter(priceCompareResult -> execute(priceCompareResult) != null ? true : false).collect(Collectors.toList());
    
        }
    
        /**
         * 单个进行过滤
         *
         * @param result
         * @return
         */
        public PriceCompareResult execute(PriceCompareResult result) {
        
            checkChains();
            for (FilterChain<PriceCompareResult> filterChain : filterChains) {
        
                try {
        
                    return filterChain.process(result);
                } catch (Exception e) {
        
                    log.error("PcResultFilterAdmin_execute-filterChain", "执行失败");
                }
            }
            return result;
        }
    
        /**
         * 查看配置有没有更新,有就重新创建
         */
        private void checkChains() {
        
            try {
        
                String filterChainConfig = CfgCenterUtil.getValue("PC_RESULT_FILTER_CHAIN", "");
                if (StringUtils.isEmpty(filterChainConfig)) {
        
                    log.info("checkChains-filterChainConfig", "配置为空");
                    return;
                }
                String newConfigMd5 = DigestUtils.md5DigestAsHex(filterChainConfig.getBytes());
                if (!newConfigMd5.equals(oldConfigMd5)) {
        
                    List<FilterChainConfig> configs = JSONArray.parseArray(filterChainConfig, FilterChainConfig.class);
                    List<FilterChain<PriceCompareResult>> list = Lists.newArrayListWithCapacity(configs.size());
                    for (FilterChainConfig config : configs) {
        
                        FilterChain<PriceCompareResult> chain = filterChainFactory.createChains(config, PriceCompareResult.class);
                        list.add(chain);
                    }
                    oldConfigMd5 = newConfigMd5;
                    filterChains.clear();
                    filterChains = list;
                }
            } catch (Exception e) {
        
                log.error("PcResultFilterAdmin_checkChains-新增或更新过滤链失败", e);
            }
        }
    
    }

8、 测试代码

package com.dgut.edu.com.filterproject;
    
    import com.dgut.edu.com.filterproject.entity.PriceCompareResult;
    import com.dgut.edu.com.filterproject.service.PcResultFilterService;
    import com.google.common.collect.Lists;
    import org.junit.Assert;
    import org.junit.jupiter.api.Test;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    
    import java.util.List;
    
    @SpringBootTest
    class FilterprojectApplicationTests {
        
        @Autowired
        private PcResultFilterService pcResultFilterService;
    
        @Test
        void contextLoads() {
        
            List<PriceCompareResult> priceCompareResultLists = getPriceCompareResultLists();
            List<PriceCompareResult> priceCompareResults = pcResultFilterService.batchExecute(priceCompareResultLists);
            Assert.assertEquals(1, priceCompareResults.size());
        }
    
        private List<PriceCompareResult> getPriceCompareResultLists() {
        
            List<PriceCompareResult> results = Lists.newArrayList();
            PriceCompareResult priceCompareResult1 = getPriceCompareResult();
            results.add(priceCompareResult1);
    
            PriceCompareResult priceCompareResult2 = getPriceCompareResult();
            priceCompareResult2.setSalesName("专场包含VIP和LUX");
            results.add(priceCompareResult2);
    
            PriceCompareResult priceCompareResult3= getPriceCompareResult();
            priceCompareResult3.setGoodsName("专场套装");
            results.add(priceCompareResult3);
    
            return results;
        }
        private PriceCompareResult getPriceCompareResult() {
        
            PriceCompareResult entity = new PriceCompareResult();
            entity.setGoodsName("商品名称");
            entity.setMerchandiseNo(10086L);
            entity.setSalesName("专场名称VIP LUP");
            entity.setSalesNo(123456L);
            return entity;
        }
    
    }

### 测试结果 ###

最后效果，输入三条数据  
只有一条满足，返回满足的一条，其他两天直接过滤  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aGVnYWE_size_16_color_FFFFFF_t_70 1]

## 总结 ##

知 道 的 越 多 ， 不 知 道 的 越 多 ， 希 望 对 你 有 帮 助 ！ \\color\{red\}知道的越多，不知道的越多，希望对你有帮助！ 知道的越多，不知道的越多，希望对你有帮助！

[Link 1]: https://download.csdn.net/download/xiaozhegaa/20041235?spm=1001.2014.3001.5503
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aGVnYWE_size_16_color_FFFFFF_t_70]: /images/20221005/5b7968b2276c4c0daa96b8e66aec88d1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aGVnYWE_size_16_color_FFFFFF_t_70 1]: /images/20221005/be004d6744f64e52a5e1c0f4d26ada5d.png