[drools]spring-boot使用drools规则引擎

一、springboot项目引用依赖如下（exclusion部分，大家根据自己的情况处理）：

        
        
            org.drools
            drools-core
            7.0.0.Final
        
        
            org.drools
            drools-compiler
            7.0.0.Final
        
        
            org.drools
            drools-decisiontables
            7.0.0.Final
            
                
                    poi
                    org.apache.poi
                
                
                    poi-ooxml
                    org.apache.poi
                
            
        
        
            org.drools
            drools-templates
            7.0.0.Final
        
        
            org.kie
            kie-spring
            7.0.0.Final
        

二、规则编写在如下图的层级（大家也可以按照情况自己选择）

三、编写config配置文件

可以看到，这里也指定了步骤二的规则文件的所在目录

@Configuration
public class DroolsAutoConfiguration {

    private static final String RULES_PATH = "rules/";

    @Bean
    @ConditionalOnMissingBean(KieFileSystem.class)
    public KieFileSystem kieFileSystem() throws IOException {
        KieFileSystem kieFileSystem = getKieServices().newKieFileSystem();
        for (Resource file : getRuleFiles()) {
            kieFileSystem.write(ResourceFactory.newClassPathResource(RULES_PATH + file.getFilename(), "UTF-8"));
        }
        return kieFileSystem;
    }

    private Resource[] getRuleFiles() throws IOException {
        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        return resourcePatternResolver.getResources("classpath*:" + RULES_PATH + "**/*.*");
    }

    @Bean
    @ConditionalOnMissingBean(KieContainer.class)
    public KieContainer kieContainer() throws IOException {
        final KieRepository kieRepository = getKieServices().getRepository();
        kieRepository.addKieModule(kieRepository::getDefaultReleaseId);
        KieBuilder kieBuilder = getKieServices().newKieBuilder(kieFileSystem());
        kieBuilder.buildAll();
        return getKieServices().newKieContainer(kieRepository.getDefaultReleaseId());
    }

    private KieServices getKieServices() {
        return KieServices.Factory.get();
    }

    @Bean
    @ConditionalOnMissingBean(KieBase.class)
    public KieBase kieBase() throws IOException {
        return kieContainer().getKieBase();
    }

    @Bean
    @ConditionalOnMissingBean(KieSession.class)
    public KieSession kieSession() throws IOException {
        KieSession kieSession = kieContainer().newKieSession();
        return kieSession;
    }

    @Bean
    @ConditionalOnMissingBean(KModuleBeanFactoryPostProcessor.class)
    public KModuleBeanFactoryPostProcessor kiePostProcessor() {
        return new KModuleBeanFactoryPostProcessor();
    }
}

四、开始使用

1)自动注入：

    @Autowired
    private KieSession kieSession;

2)例子：

    /**
     * 通过参数，获取对应的模板key
     * @param contractType 合同类型
     * @param subjectId 合同主体Id,对应t_contract_detail的id
     * @param subjectName 合同主体名称
     * @param workAreaName 工作地点
     * @return String
     */
    public String getContractTemplateKeyFormRules(String contractType,Long subjectId,String subjectName, String workAreaName){
        // load up the knowledge base
        EntryContractTemplateRuleParam ruleParam = new EntryContractTemplateRuleParam();
        ruleParam.setContractType(Optional.ofNullable(contractType).orElse(""));
        ruleParam.setSubjectId(Optional.ofNullable(subjectId).orElse(-1L));
        ruleParam.setSubjectName(Optional.ofNullable(subjectName).orElse(""));
        ruleParam.setWorkAreaName(Optional.ofNullable(workAreaName).orElse(""));
        ruleParam.setActive(active);
        //插入
        kieSession.insert(ruleParam);
        //执行规则
        kieSession.fireAllRules();
        return ruleParam.getTemplateKey();
    }

3)规则编写例子（就是写在EntryContractTemplateRule.drl中的内容）：
通过在java代码中传入参数2)中的参数，规则引擎会解析到EntryContractTemplateRule.drl中配置的规则，然后规则中使用m.setTemplateKey(“0_0”);
进行赋值并返回，如果命中如下的规则getContractTemplateKeyFormRules方法就会返回字符串"0_0"，完成本次规则的命中。

rule "XX劳动合同模板"
salience 0
no-loop true
lock-on-active
    when
        m : EntryContractTemplateRuleParam(!active.equals("production") && contractType.equals("1") &&
        subjectId != 590 &&
        subjectId != 154 &&
        subjectId != 589 &&
        subjectId != 67 &&
        subjectId != 75 &&
        subjectId != 173)
    then
        m.setTemplateKey("0_0");
        
end

五、快速教程结束