Java规则引擎drools：drt动态生成规则并附上具体项目逻辑

/**
 * 加载规则
 */

public void loadRule() {
    try {
        List<RuleDTO> ruleDTOs = getActivityRuleList();
        log.info("{}条加入规则引擎", ruleDTOs.size());
        if (!ruleDTOs.isEmpty()) {
            RuleGenerator generator = new RuleGenerator();
            generator.generateRules(ruleDTOs);
        }
    } catch (Exception e) {
        log.error("RuleService.loadRule。e={}",e.getMessage(), e);
    }
}

/**
     * 从数据库里面取规则
     */
    public List<RuleDTO> getActivityRuleList() {
        Date begin = Date.from(LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant());
        Date end = Date.from(LocalDateTime.now().plusDays(1).atZone(ZoneId.systemDefault()).toInstant());

        List<ActivityRule> list = testService.selectAll();
        List<RuleDTO> ruleDTOList = new ArrayList<>();
        for (ActivityRule dto : list) {
            RuleDTO ruleDTO = new RuleDTO();
            ruleDTO.setBeginTime(begin);
            ruleDTO.setEndTime(end);
            ruleDTO.setRule(dto);
            ruleDTOList.add(ruleDTO);
        }
        return ruleDTOList;
    }

/**
 * 根据传递进来的参数对象生规则
 *
 * @param ruleDTOs
 */
public void generateRules(List<RuleDTO> ruleDTOs) {
    List<String> ruleDrls = new ArrayList<>();
    for (int i = 0; i < ruleDTOs.size(); i++) {
        //规则的生成
        String drlString = applyRuleTemplate(ruleDTOs.get(i));
        ruleDrls.add(drlString);
        log.info("规则引擎加载规则,id-{}", ruleDTOs.get(i).getRule().getId());
    }
    //规则的加载
    createOrRefreshDrlInMemory(ruleDrls);
}

/**
     * 根据Rule生成drl的String
     */
    private String applyRuleTemplate(RuleDTO ruleDTO) {
        Map<String, Object> data = prepareData(ruleDTO);
//        log.info("rule={}", JSON.toJSON(ruleDTO));
        ObjectDataCompiler objectDataCompiler = new ObjectDataCompiler();
        return objectDataCompiler.compile(Arrays.asList(data), Thread.currentThread().getContextClassLoader().getResourceAsStream("give-reward-rule-template.drt"));
    }

   /**
     * 根据Rule生成drl的map data
     */
    protected Map<String, Object> prepareData(RuleDTO ruleDTO) {
        Map<String, Object> data = new HashMap<>();
        ActivityRule rule = ruleDTO.getRule();
        data.put("ruleCode", ruleDTO.hashCode());
        data.put("beginTime", DateUtil.dateToStringFormat(ruleDTO.getBeginTime(), "dd-MMM-yyyy"));
        data.put("endTime", DateUtil.dateToStringFormat(ruleDTO.getEndTime(), "dd-MMM-yyyy"));
        data.put("eventType", FactManager.getFactClassByEvent(rule.getEvent()).getName());
        data.put("rule", rule.getRuleValue());
        data.put("awardeeType", rule.getAwardeeType());
//        data.put("ruleId", rule.getId());
//        data.put("joinChannels", ruleDTO.getJoinChannel());
//        data.put("priority", rule.getPriority());
//        log.info("data={}", JSON.toJSON(data));
        return data;
    }

/**
 * 根据String格式的Drl生成Maven结构的规则
 *
 * @param rules
 */
private void createOrRefreshDrlInMemory(List<String> rules) {
    KieServices kieServices = KieServices.Factory.get();
    KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
    kieFileSystem.generateAndWritePomXML(RuleExecutor.getReleaseId());
    for (String str : rules) {
        kieFileSystem.write("src/main/resources/" + UUID.randomUUID() + ".drl", str);
        log.info("str={}", str);
    }
    KieBuilder kb = kieServices.newKieBuilder(kieFileSystem).buildAll();
    if (kb.getResults().hasMessages(Message.Level.ERROR)) {
        log.error("create rule in kieFileSystem Error", kb.getResults());
        throw new IllegalArgumentException("生成规则文件失败");
    }
    doAfterGenerate(kieServices);
}

    /**
     * 触发规则
     */
    public void useRule(String userId, String phone) {
        BaseFact fact = buildBaseFact(userId);
        /**
         * 因为是uuid所以修改了的规则，重载加载是新的drl，故从数据库动态加载之时，is_delete属性要注意
         * */
        String orderId = UUID.randomUUID().toString();
        /**
         * 此处应当是从其他服务获取的的消息体，而不是空值
         * */
        RegisterMqDTO domain = new RegisterMqDTO();
        domain.setTelephone(phone);
        try {
            /*可以知道一条信息，匹配了多少个规则，成功了几个*/
            RuleExecutorResult ruleExecutorResult = beforeExecute(orderId, fact, domain);
            log.info("RuleService|useRule|ruleExecutorResult={}", JSON.toJSON(ruleExecutorResult));
//            Assert.isTrue(ruleExecutorResult.getFailure() == 0, String.format("有%d条规则执行失败", ruleExecutorResult.getFailure()));
        } catch (Exception e) {
            log.error("RuleService|useRule|class={},orderId={}, userId={}, 规则执行异常:{}", this.getClass().getName(), orderId, "123456789", e.getMessage(), e);
        }
    }

    /**
     * 生成初始的baseFact
     */
    public BaseFact buildBaseFact(String userId) {
        BaseFact fact = new BaseFact();
//        此处应获取用户的信息
//        fact.setCust();
        fact.setUserId(userId);
        return fact;
    }

/**
 * 执行前
 */
public RuleExecutorResult beforeExecute(String orderId, BaseFact fact, RegisterMqDTO domain) {
    RegisterFact registerFact = buildRegisterFact(domain);
    CopyUtil.copyPropertiesCglib(fact, registerFact);
    log.info("RuleService|beforeExecute|{}事件的orderId={}, RegisterMqDTO={}", registerFact.getClass().getAnnotation(Fact.class).value(), orderId, domain);
    return RuleExecutor.execute(registerFact, orderId);
}

/**
 * 生成初始的registerFact
 */
private RegisterFact buildRegisterFact(RegisterMqDTO domain) {
    RegisterFact registerFact = new RegisterFact();

    CopyUtil.copyPropertiesCglib(domain, registerFact);
    return registerFact;
}

/**
 * modify by xiaohua
 * KieBase被抽取
 *
 * @param fact
 * @param orderId
 * @return 规则执行结果
 * @author xiaohua 2016年10月24日 下午2:09:12
 */
public static RuleExecutorResult execute(BaseFact fact, String orderId) {
    LOGGER.info("RuleExecutor|execute|fact={}", JSON.toJSON(fact));
    StatelessKieSession statelessKieSession = getKieBase().newStatelessKieSession();
    RuleExecuteGlobal global = new RuleExecuteGlobal();
    global.setUserId(fact.getUserId());
    global.setOrderId(orderId);
    global.setFactObj(fact);
    global.setResult(new RuleExecutorResult());
    statelessKieSession.getGlobals().set("globalParams", global);
    statelessKieSession.execute(fact);

    return global.getResult();
}