drools 基于数据库实现动态规则，即为将规则文件字符串 存在数据库中，然后规则引擎执行的时候将规则从数据库中读取出来，写入到规则引擎KieFileSystem中，加载规则。从而实现，修改数据库后，即可及时执行规则。

创建springboot + mybatis 项目

https://abelyang.blog.csdn.net/article/details/89296273

导入drools 所需jar包

  <dependency>
            <groupId>org.kie</groupId>
            <artifactId>kie-api</artifactId>
            <version>6.5.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-core</artifactId>
            <version>6.5.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-compiler</artifactId>
            <version>6.5.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-decisiontables</artifactId>
            <version>6.5.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-templates</artifactId>
            <version>6.5.0.Final</version>
        </dependency>

在执行规则引擎的service 处的核心代码如下：
从数据加载规则字符串加载入规则引擎

 String rules = "";
        Rules ru = rulesDao.getById(id);
        if (ru != null && ru.getRules() != null) {
            rules = ru.getRules();
        }

        KieServices kieServices = KieServices.Factory.get();
        KieFileSystem kfs = kieServices.newKieFileSystem();
        kfs.write("src/main/resources/rules/rules.drl", rules.getBytes());
        KieBuilder kieBuilder = kieServices.newKieBuilder(kfs).buildAll();
        Results results = kieBuilder.getResults();
        if (results.hasMessages(org.kie.api.builder.Message.Level.ERROR)) {
            System.out.println(results.getMessages());
            throw new IllegalStateException("### errors ###");
        }
        KieContainer kieContainer = kieServices.newKieContainer(kieServices.getRepository().getDefaultReleaseId());
        KieBase kieBase = kieContainer.getKieBase();
        KieSession ksession = kieBase.newKieSession();

        Message message = new Message();
        message.setStatus("0");
        ksession.insert(message);
        ksession.fireAllRules();

启动

数据库修改规则

重新请求

源码：https://github.com/527515025/drools-springboot/tree/master/springboot-drools-dynamic-db