规则引擎drools封装

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