规则引擎drools封装

2024-03-16 21:39:40

一.前言

网上规则引擎drools介绍很多,并且有很多细致的说明,作者也不敢托大说自己的好用,但作者经过2个项目使用过规则引擎后,自己对规则引擎的理解并进行封装,对规则内容及如何使用,有自己的一番实践,并提供源代码,供大家参考

二.设计思路及具体代码

首先我希望是轻量级的使用drools,不希望使用太过复杂的架构,以这种思路入手,就可以与任何项目轻易融入,这样就需要能够将drools规则的来源,从规则文件(drl)中可以从maven和自己的数据库中获取,脚本是动态的,配合drools6.5支持通过maven接入的规则的API,就可以做到从任何处获取规则内容

一个工具类DroolsUtils


package com.vip.jie.rule.util;
 
import org.drools.compiler.kie.builder.impl.InternalKieModule;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.ReleaseId;
import org.kie.api.builder.model.KieBaseModel;
import org.kie.api.builder.model.KieModuleModel;
import org.kie.api.builder.model.KieSessionModel;
import org.kie.api.conf.EqualityBehaviorOption;
import org.kie.api.conf.EventProcessingOption;
 
import java.io.IOException;
 
 
 
/**
 * 动态生成kjar
 * @author jie01.zhu
 * @DateTime 2018/3/19 22:14
 */
public class DroolsUtils {
 
  /**
   * 创建默认的kbase和stateful的kiesession
  *
     * @param ks
  * @param isdefault
   * @return
    */
  private static KieFileSystem createKieFileSystemWithKProject(KieServices ks, boolean isdefault) {
     KieModuleModel kproj = ks.newKieModuleModel();
      KieBaseModel kieBaseModel1 = kproj.newKieBaseModel("KBase").setDefault(isdefault)
              .setEqualsBehavior(EqualityBehaviorOption.EQUALITY)
             .setEventProcessingMode(EventProcessingOption.STREAM);
      // Configure the KieSession.
      kieBaseModel1.newKieSessionModel("KSession").setDefault(isdefault)
             .setType(KieSessionModel.KieSessionType.STATEFUL);
      KieFileSystem kfs = ks.newKieFileSystem();
      kfs.writeKModuleXML(kproj.toXML());
     return kfs;
   }
 
  /**
   * 创建kjar的pom
  *
     * @param releaseId
   * @param dependencies
    * @return
    */
  private static String getPom(ReleaseId releaseId, ReleaseId... dependencies) {
      String pom = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
              + "<project xmlns=\"http://maven.apache.org/POM/4.0.0\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
              + "         xsi:schemaLocation=\"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd\">\n"
               + "  <modelVersion>4.0.0</modelVersion>\n" + "\n" + "  <groupId>" + releaseId.getGroupId()
             + "</groupId>\n" + "  <artifactId>" + releaseId.getArtifactId() + "</artifactId>\n" + "  <version>"
             + releaseId.getVersion() + "</version>\n" + "\n";
       if (dependencies != null && dependencies.length > 0) {
          pom += "<dependencies>\n";
           for (ReleaseId dep : dependencies) {
              pom += "<dependency>\n";
             pom += "  <groupId>" + dep.getGroupId() + "</groupId>\n";
             pom += "  <artifactId>" + dep.getArtifactId() + "</artifactId>\n";
                pom += "  <version>" + dep.getVersion() + "</version>\n";
             pom += "</dependency>\n";
            }
           pom += "</dependencies>\n";
      }
       pom += "</project>";
     return pom;
   }
 
  /**
   * 初始化一个kjar：把原有的drl包含进新建的kjar中
    *
     * @param ks
  * @param releaseId
   * @return
    * @throws IOException
    */
  public static InternalKieModule initKieJar(KieServices ks, ReleaseId releaseId) throws IOException {
      KieFileSystem kfs = createKieFileSystemWithKProject(ks, true);
        kfs.writePomXML(getPom(releaseId));
     KieBuilder kieBuilder = ks.newKieBuilder(kfs);
      if (!kieBuilder.buildAll().getResults().getMessages().isEmpty()) {
            throw new IllegalStateException("Error creating KieBuilder.");
     }
       return (InternalKieModule) kieBuilder.getKieModule();
 }
 
  public static InternalKieModule createKieJar(KieServices ks, ReleaseId releaseId, DroolsResource droolsResource) {
      KieFileSystem kfs = createKieFileSystemWithKProject(ks, true);
        kfs.writePomXML(getPom(releaseId));
     kfs.write("src/main/resources/" + droolsResource.getTargetResourceName(), droolsResource.getResource());
 
      KieBuilder kieBuilder = ks.newKieBuilder(kfs);
      if (!kieBuilder.getResults().getMessages().isEmpty()) {
           throw new IllegalStateException(
                   "Error creating KieBuilder. errorMsg:" + kieBuilder.getResults().getMessages());
      }
      return (InternalKieModule) kieBuilder.getKieModule();
    }
 
 
}

重点调用参考:


String fileName = "jie-" + group + "-rules";
/**
 * 指定kjar包
 */
final ReleaseId releaseId = kieServices.newReleaseId("com.vip.jie", fileName, "1.0.0");
 
log.info("DroolsGetKieSession fileName:{}", fileName);
log.info("[DroolsGetKieSession] drlStr:{}", drlStr);
// 创建初始化的kjar
InternalKieModule kJar = DroolsUtils.createKieJar(kieServices, releaseId,
       new DroolsResource(ResourceFactory.newByteArrayResource(drlStr.getBytes()),
              fileName + ".drl"));

其次再将如何让使用者可以很灵活的接入,利用可变参数类型,将入参对象无限制传入,由规则脚本去决定入参的变化,通过此种方式可以比较好的实现业务灵活接入

如下单元测试类:


package com.vip.jie.rule.service.impl;
 
 
import com.vip.jie.rule.object.User;
import com.vip.jie.rule.service.RuleManager;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
 
import static junit.framework.TestCase.fail;
 
/**
 * 规则测试
 *  @author jie01.zhu
 *   @DateTime 2018/3/19 21:17
 *
 */
@Slf4j
public class RuleManagerImplTest {
 
  private RuleManager ruleManager = new RuleManagerImpl();
 
   private String getRuleContent() {
     StringBuilder stringBuilder = new StringBuilder();
 
       stringBuilder.append("import com.vip.jie.rule.object.User;\n");
        stringBuilder.append("rule test1 when\n");
     stringBuilder.append("user : User(age==20)\n");
        stringBuilder.append("then\n");
        stringBuilder.append("user.setName(\"张三\");\n");
       stringBuilder.append("end\n");
     return stringBuilder.toString();
  }
 
  @Test
    public void executeRule1() throws Exception {
 
        User user = new User();
       user.setAge(20);
 
      //调用规则
        ruleManager.executeRule("test1", getRuleContent(), user);
      log.info("test result:{}", user.toString());
 
      if (!"张三".equals(user.getName())) {
          fail("error rule");
        }
   }
 
  @Test
    public void executeRule2() throws Exception {
 
        User user = new User();
       user.setAge(21);
 
      //调用规则
        ruleManager.executeRule("test1", getRuleContent(), user);
      log.info("test result:{}", user.toString());
 
      if ("张三".equals(user.getName())) {
           fail("error rule");
        }
   }
}

三.对应示例源代码获取方式

githup:

https://github.com/jie01/drools-demo

csdn资源下载地址:

https://download.csdn.net/download/vipshop_fin_dev/10296393

还有一些关于安全性及与spring的封装思路,作者表示还会继续完善,并还不是最终版本,有需要可以持续关注-_-!

与当前文章有关联的链接

业务框架之个性化监控方案

vipshop_ebs/朱杰

2018-03-19

原文地址：https://blog.csdn.net/vipshop_fin_dev/article/details/79618067

码农公寓

网上规则引擎drools介绍很多,并且有很多细致的说明,作者也不敢托大说自己的好用,但作者经过2个项目使用过规则引擎后,自己对规则引擎的理解并进行封装,对规则内容及如何使用,有自己的一番实践,并提供源代码,供大家参考

与当前文章有关联的链接

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