SpringBoot integrated drools

1. Background

In the previous article, we learned some basic syntax of drools , in this article, we implemented the integration in SpringBoot drools .

2. Demand

We need to determine whether the user can play the game in drools .

规则一： If the user's age age>=18 , then 可以 play the game.
规则二： if the user's age age<18 , then 不可以 play the game.

3. Realize

3.1 Introducing jar package

 <dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-bom</artifactId>
            <type>pom</type>
            <version>7.69.0.Final</version>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.6.7</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-compiler</artifactId>
    </dependency>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-mvel</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.22</version>
    </dependency>
</dependencies>

The drools springboot jar package is introduced here.

3.2 Write drools configuration class

 @Configuration
public class DroolsConfig {

    @Bean
    public KieContainer kieContainer() {
        KieServices kieServices = KieServices.get();
        return kieServices.getKieClasspathContainer();
    }
}

3.3 Writing the Person object

It can be simply understood as the drools Fact object in ---93bec35fad740d619c00c57d3f4bcfe2---. Inserted into working memory in drools is the Fact object.

 @Data
@AllArgsConstructor
public class Person {
    private String name;
    private Integer age;
    // 是否可以玩游戏，此字段的值，由 drools 引擎计算得出
    private Boolean canPlayGame;
}

canPlayGame : The value of this field is calculated by the drools engine.

3.4 Write drl file

 package rules

import com.huan.drools.fact.Person

// 用户可以玩游戏
rule "rule_person_can_play_game"
    when
        $person: Person( age >= 18)
    then
        $person.setCanPlayGame(true);
        System.out.println("触发规则:" + drools.getRule().getName());
end

// 用户不可以玩游戏
rule "rule_person_Can't_play_game"
    when
        $person: Person( age < 18)
    then
        $person.setCanPlayGame(false);
        System.out.println("触发规则:" + drools.getRule().getName());
end

There are two rules written above, both of which are judged according to age , so as to calculate whether the user can play the game canPlayGame .

3.5 Write the kmodule.xml file

The path of ---aa24484f2aedef4b0a0b0fa5a067d205 kmodule.xml is located in the src/main/resources/META-INF directory.

 <kmodule xmlns="http://www.drools.org/xsd/kmodule">
    <kbase name="kabse" packages="rules" default="false">
        <ksession name="ksession" default="false" type="stateful">
            <consoleLogger/>
            <listeners>
                <ruleRuntimeEventListener type="org.kie.api.event.rule.DebugRuleRuntimeEventListener"/>
                <processEventListener type="org.drools.core.event.DebugProcessEventListener"/>
                <agendaEventListener type="org.drools.core.event.DebugAgendaEventListener"/>
            </listeners>
        </ksession>
    </kbase>
</kmodule>

3.6 Write Controller trigger rules

 @RestController
public class PersonController {

    private final KieContainer kieContainer;

    public PersonController(KieContainer kieContainer) {
        this.kieContainer = kieContainer;
    }

    /**
     * 调用drools rule判断用户是否可以玩游戏
     */
    @GetMapping("canPlayGame")
    public Person canPlayGame(Person person) {
        KieSession kieSession = kieContainer.newKieSession("ksession");
        try {
            kieSession.insert(person);
            kieSession.fireAllRules();
        } finally {
            kieSession.dispose();
        }
        return person;
    }
}

3.7 Testing

3.7.1 User's age >= 18 years old

 ➜ curl http://localhost:8081/canPlayGame\?name\=huan\&age\=20
{"name":"huan","age":20,"canPlayGame":true}

It can be seen that the value calculated in drools canPlayGame value is `true

3.7.2 User's age < 18 years old

 ➜ curl http://localhost:8081/canPlayGame\?name\=huan\&age\=16
{"name":"huan","age":20,"canPlayGame":false}

It can be seen that the value calculated in drools canPlayGame is false

4. Complete code

https://gitee.com/huan1993/spring-cloud-parent/tree/master/drools/drools-integrated-springboot