Spring Boot+Drools规则引擎整合详解

目的

官方的Drools范例大都是基于纯Java项目或Maven项目，而基于Spring Boot项目的很少。

本文介绍如何在Spring Boot项目上加上Drools规则引擎。

POM依赖

POM文件如下：

									<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

									 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

									 <modelVersion>4.0.0</modelVersion>

									 <groupId>com.galaxyyao</groupId>

									 <artifactId>springbootdroolstest1</artifactId>

									 <version>1.0.0</version>

									 <packaging>jar</packaging>

									 <name>springbootdroolstest1</name>

									 <url>http://maven.apache.org</url>

									 <properties>

									  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

									  <java.version>1.8</java.version>

									 </properties>

									 <parent>

									  <groupId>org.springframework.boot</groupId>

									  <artifactId>spring-boot-starter-parent</artifactId>

									  <version>1.5.2.RELEASE</version>

									 </parent>

									 <dependencies>

									  <dependency>

									   <groupId>org.springframework.boot</groupId>

									   <artifactId>spring-boot-starter-web</artifactId>

									  </dependency>

									  <dependency>

									   <groupId>org.drools</groupId>

									   <artifactId>drools-core</artifactId>

									   <version>7.0.0.Final</version>

									  </dependency>

									  <dependency>

									   <groupId>org.drools</groupId>

									   <artifactId>drools-compiler</artifactId>

									   <version>7.0.0.Final</version>

									  </dependency>

									  <dependency>

									   <groupId>org.drools</groupId>

									   <artifactId>drools-decisiontables</artifactId>

									   <version>7.0.0.Final</version>

									  </dependency>

									  <dependency>

									   <groupId>org.drools</groupId>

									   <artifactId>drools-templates</artifactId>

									   <version>7.0.0.Final</version>

									  </dependency>

									  <dependency>

									   <groupId>org.kie</groupId>

									   <artifactId>kie-api</artifactId>

									   <version>7.0.0.Final</version>

									  </dependency>

									 </dependencies>

									 <build>

									  <plugins>

									   <plugin>

									    <artifactId>maven-compiler-plugin</artifactId>

									   </plugin>

									   <plugin>

									    <groupId>org.springframework.boot</groupId>

									    <artifactId>spring-boot-maven-plugin</artifactId>

									   </plugin>

									   <plugin>

									    <groupId>org.codehaus.mojo</groupId>

									    <artifactId>exec-maven-plugin</artifactId>

									    <configuration>

									     <executable>java</executable>

									     <arguments>

									      <argument>com.galaxyyao.springbootdroolstest1.SpringBootDroolsTest1Application</argument>

									     </arguments>

									    </configuration>

									   </plugin>

									  </plugins>

									 </build>

									</project>

其中比较需要注意的是使用了exec-maven-plugin插件，不然无法启动

引用的Drools包的版本可以自行调整。

Resources

在src/main/resources下添加两个目录：

META-INF和rules

META-INF下添加kmodule.xml，内容如下：

									<kmodule xmlns="http://jboss.org/kie/6.0.0/kmodule">

									 <kbase name="rules" packages="rules">

									  <ksession name="ksession-rules"/>

									 </kbase>

									</kmodule>

rules目录下添加一个简单的Hello World规则

									package com.galaxyyao.springbootdroolstest1

									import com.galaxyyao.springbootdroolstest1.domain.Message

									dialect "mvel"

									rule "Hello World"

									 dialect "mvel"

									 when

									  m : Message(status.equals(Message.HELLO), message : message )

									 then

									  System.out.println( message);

									 modify ( m ) { message = "Goodbye cruel world",status = Message.GOODBYE };

									end

									rule "Good Bye"

									 dialect "java"

									 when

									  Message( status == Message.GOODBYE, message : message )

									 then

									  System.out.println( message );

									end

Domain层

Domain层定义一个Drools中需要使用到的Model：

									package com.galaxyyao.springbootdroolstest1.domain;

									public class Message {

									 public static final Integer HELLO = 0;

									 public static final Integer GOODBYE = 1;

									 private String message;

									 private Integer status;

									 public String getMessage() {

									  return this.message;

									 }

									 public void setMessage(String message) {

									  this.message = message;

									 }

									 public Integer getStatus() {

									  return this.status;

									 }

									 public void setStatus(Integer status) {

									  this.status = status;

									 }

									}

Service层

Service层负责实际运行规则：

									package com.galaxyyao.springbootdroolstest1.service;

									import org.kie.api.KieServices;

									import org.kie.api.runtime.KieContainer;

									import org.kie.api.runtime.KieSession;

									import org.springframework.stereotype.Service;

									import com.galaxyyao.springbootdroolstest1.domain.Message;

									@Service

									public class DroolsService {

									 public String fireRule() {

									 // load up the knowledge base

									  KieServices ks = KieServices.Factory.get();

									  KieContainer kContainer = ks.getKieClasspathContainer();

									  KieSession kSession = kContainer.newKieSession("ksession-rules");

									  // go !

									  Message message = new Message();

									  message.setMessage("Hello World");

									  message.setStatus(Message.HELLO);

									  kSession.insert(message);//插入

									  kSession.fireAllRules();//执行规则

									  kSession.dispose();

									  return message.getMessage();

									 }

									}