drools是什么

Drools 是一个开源的业务规则管理系统 (BRMS) 和决策管理系统 (DMS)，它提供了一个基于规则引擎的方法来管理和执行业务规则和决策。

Drools 允许用户定义、管理和执行规则，它提供了一种基于声明式语言的方式来表达业务规则和决策，这使得规则和决策更加易于理解和维护。Drools 可以与 Java 应用程序集成，也可以作为独立的服务运行。Drools 还提供了一些高级功能，如事务处理、事件处理和实时决策等。

使用 Drools 可以帮助企业更加灵活地管理和调整业务规则和决策，以快速适应不断变化的业务需求。

简单使用例子

该例子在网上找的，整理时未找到出处，如果哪位发现了告知我一下
实现一个商品打折的规则，买1件不打折，买2件打98折，买3件打0.85折
代码如下：

• 创建文件夹

mkdir my-project
cd my-project 
mkdir -p src/main/java/com/example
mkdir -p src/main/resources

• 初始化pom.xml文件

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>my-project</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>my-project</name>
  <url>http://maven.apache.org</url>


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


  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.3</version>
    </dependency>
    <dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-compiler</artifactId>
    </dependency>
    <dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-mvel</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <!-- Maven Compiler Plugin -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.8.1</version>
        <configuration>
          <source>11</source>
          <target>11</target>
        </configuration>
      </plugin>
      <!-- Maven Surefire Plugin -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.0.0-M5</version>
      </plugin>
    </plugins>
  </build>

</project>

• 初始化META-INF/kmodule.xml，定义drools元数据信息

<kmodule xmlns="http://www.drools.org/xsd/kmodule">
    <!--
        kbase 可以存在多个
        name: 指定kbase的名字，需要是唯一的
        packages: 包名，可以理解为到src/main/resources目录下查找这个包名下的规则文件,多个包使用逗号分割
        default: 当前kbase是否是默认的kbase
    -->
    <kbase name="shop-kabse" packages="com.example.shop" default="false">
        <!--
            ksession 可以存在多个
            name: 指定ksession 的名字，需要唯一
            defalut: 当前ksession在这个kbase下是否是默认的
            type: 指定当前ksession是否是有状态的 stateless表示是无状态的
        -->
        <ksession name="shop-ksession" default="false" type="stateless"/>
        <ksession name="shop-ksession-stateful" default="false" type="stateful"/>
    </kbase>
</kmodule>

shop-ksession和shop-ksession-stateful将在调用StatelessKieSession kieSession = kieContainer.newStatelessKieSession("shop-ksession");时使用

• com/example/shop/shop-discount.drl,定义drools文件

// 包名，必须防止到第一行，这个名字需要和 kbase中package属性的值一致
package com.example.shop

/**
 * 导入类
 */
import com.example.CustomerOrder

// 定义规则
rule "shop-rule-01"
    when
        // 模式匹配：到工作内存中查找CustomerOrder，并且这个对象的purchaseQuantity值需要是1，
        // 如果条件成立，$order是绑定变量名，一般以$开头，和fact对象区分开
        $order:CustomerOrder(purchaseQuantity == 1)
    then
        System.out.println("匹配规则 shop-rule-01");
        // 赋值，此处赋值后，在Java代码中获取获取到赋值后的值
        $order.setDiscount(1D);
end

rule "shop-rule-02"
    when
        $order:CustomerOrder(purchaseQuantity == 2)
    then
        System.out.println("匹配规则 shop-rule-02");
        $order.setDiscount(0.98);
end

rule "shop-rule-03"
    when
        $order:CustomerOrder(purchaseQuantity >= 3)
    then
        System.out.println("匹配规则 shop-rule-03");
        $order.setDiscount(0.85);
end

• 初始化领域对象com/example/CustomerOrder.java

package com.example;

public class CustomerOrder {
    /**
     * 购买了几件衣服
     */
    private Integer purchaseQuantity;
    /**
     * 最终打多少折
     */
    private Double discount;

    public CustomerOrder(Integer purchaseQuantity) {
        this.purchaseQuantity = purchaseQuantity;
    }

    public Integer getPurchaseQuantity() {
        return purchaseQuantity;
    }

    public void setPurchaseQuantity(Integer purchaseQuantity) {
        this.purchaseQuantity = purchaseQuantity;
    }

    public Double getDiscount() {
        return discount;
    }

    public void setDiscount(Double discount) {
        this.discount = discount;
    }
}

• 准备调用文件com/example/App.java

package com.example;

import org.kie.api.KieServices;
import org.kie.api.event.rule.DebugRuleRuntimeEventListener;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.StatelessKieSession;

/**
 * Hello world!
 */
public class App {
    public static void main(String[] args) {
        // 无状态session测试
        statelessSessionTest();
        // 有状态session测试
        statefulSessionTest();
    }
    private static void statelessSessionTest() {
        // 获取kie services
        KieServices kieServices = KieServices.get();
        // 获取kie容器对象
        KieContainer kieContainer = kieServices.getKieClasspathContainer();
        // 获取kie session , 此处获取的是无状态的session，因为 <ksession name="shop-ksession" default="false" type="stateless"/>
        // 中type="stateless"就是无状态的session
        StatelessKieSession kieSession = kieContainer.newStatelessKieSession("shop-ksession");
        // 创建一个对象，可以理解为 Fact对象，即事实对象
        CustomerOrder customerOrder = new CustomerOrder(2);
        // 添加监听器，便于观察日志
        kieSession.addEventListener(new DebugRuleRuntimeEventListener());
        // 无状态的session只需要执行 execute 方法即可。
        kieSession.execute(customerOrder);

        System.err.println("通过规则后，获取到的折扣为:" + customerOrder.getDiscount());
    }

    private static void statefulSessionTest() {
        // 获取kie services
        KieServices kieServices = KieServices.get();
        // 获取kie容器对象
        KieContainer kieContainer = kieServices.getKieClasspathContainer();
        // 获取kie session , 此处获取的是有状态的session
        KieSession kieSession = kieContainer.newKieSession("shop-ksession-stateful");
        // 创建一个对象，可以理解为 Fact对象，即事实对象
        CustomerOrder customerOrder = new CustomerOrder(3);
        // 添加监听器，便于观察日志
        kieSession.addEventListener(new DebugRuleRuntimeEventListener());
        // 将customerOrder对象加入到工作内存中
        kieSession.insert(customerOrder);
        // 触发所有的规则，如果只想触发指定的规则，则使用fireAllRules(AgendaFilter agendaFilter)方法
        kieSession.fireAllRules();

        // 有状态的session一定需要调用dispose方法
        kieSession.dispose();

        System.err.println("通过规则后，获取到的折扣为:" + customerOrder.getDiscount());
    }
}

• 执行效果

11:03:39.746 [main] DEBUG org.kie.api.internal.utils.ServiceDiscoveryImpl - Service org.kie.api.internal.weaver.KieWeavers is implemented by org.kie.internal.services.KieWeaversImpl@3967e60c
11:03:39.836 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Found kmodule: file:/E:/nick/drools/my-project/target/classes/META-INF/kmodule.xml
11:03:39.839 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - KieModule URL type=file url=/E:/nick/drools/my-project/target/classes
11:03:39.993 [main] WARN org.drools.compiler.kie.builder.impl.ClasspathKieProject - Unable to find pom.properties in /E:/nick/drools/my-project/target/classes
11:03:39.996 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Recursed up folders, found and used pom.xml E:\nick\drools\my-project\pom.xml
11:03:39.997 [main] INFO org.drools.compiler.kie.builder.impl.InternalKieModuleProvider - Creating KieModule for artifact com.example:my-project:1.0-SNAPSHOT
11:03:39.998 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - Discovered classpath module com.example:my-project:1.0-SNAPSHOT
11:03:39.999 [main] DEBUG org.drools.compiler.kie.builder.impl.KieRepositoryImpl - KieModule was added: FileKieModule[releaseId=com.example:my-project:1.0-SNAPSHOT,file=E:\nick\drools\my-project\target\classes]
11:03:40.000 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - Start creation of KieBase: shop-kabse
11:03:40.008 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
11:03:40.030 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
11:03:40.030 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
11:03:40.368 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - End creation of KieBase: shop-kabse
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:1:1875532039:1875532039:1:DEFAULT:NON_TRAIT:com.example.CustomerOrder:com.example.CustomerOrder@6fca5907], getObject()=com.example.CustomerOrder@6fca5907, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:1:1875532039:1875532039:1:DEFAULT:NON_TRAIT:com.example.CustomerOrder:com.example.CustomerOrder@6fca5907], originOffset=-1, propagationNumber=2, rule=null, type=INSERTION]]
11:03:40.387 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now FIRING_ALL_RULES
匹配规则 shop-rule-02
11:03:40.398 [main] DEBUG org.drools.core.common.DefaultAgenda - State was FIRING_ALL_RULES is now HALTING
11:03:40.398 [main] DEBUG org.drools.core.common.DefaultAgenda - State was HALTING is now INACTIVE
11:03:40.398 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now DISPOSED
11:03:40.401 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now FIRING_ALL_RULES
匹配规则 shop-rule-03
11:03:40.401 [main] DEBUG org.drools.core.common.DefaultAgenda - State was FIRING_ALL_RULES is now HALTING
11:03:40.401 [main] DEBUG org.drools.core.common.DefaultAgenda - State was HALTING is now INACTIVE
11:03:40.401 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now DISPOSED
通过规则后，获取到的折扣为:0.98
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:1:609825180:609825180:1:DEFAULT:NON_TRAIT:com.example.CustomerOrder:com.example.CustomerOrder@2459319c], getObject()=com.example.CustomerOrder@2459319c, getKnowledgeRuntime()=KieSession[1], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:1:609825180:609825180:1:DEFAULT:NON_TRAIT:com.example.CustomerOrder:com.example.CustomerOrder@2459319c], originOffset=-1, propagationNumber=2, rule=null, type=INSERTION]]
通过规则后，获取到的折扣为:0.85

Process finished with exit code 0

处理多个数据

这一个按钮处理一个list对象，本例子从内存内读取对象列表，理论上该对象数据可以从数据库中获取。

• 添加规则文件com/example/retire/retire-rules.drl

// 包名，必须防止到第一行，这个名字需要和 kbase中package属性的值一致
package com.example.retire

/**
 * 导入类
 */
import com.example.Person

// 定义规则
rule "retire-rule-01"
    when
        // 模式匹配：到工作内存中查找Person，并且这个对象的家里需要有矿
        // 如果条件成立，$person，一般以$开头，和fact对象区分开
        $person:Person(hasMine == true)
    then
        System.out.println($person.getName()+"：你家里有矿，快快退休");
        // 赋值，此处赋值后，在Java代码中获取获取到赋值后的值
        $person.setRetire(true);
end

rule "retire-rule-02"
    when //家里没矿，又小于65岁，那老实工作吧
        $person:Person(hasMine == false, age  < 65 )
    then
        System.out.println($person.getName()+"：家里穷，再干几年吧");
        $person.setRetire(false);
end

rule "retire-rule-03"
    when //家里没矿，又大于等于65岁，没办法，干不动了，退休吧
       $person:Person(hasMine == false, age  >= 65 )
    then
       System.out.println($person.getName()+"：年纪到了，牛都干不动了，退了退了");
       $person.setRetire(true);
end

• 修改元数据文件META-INF/kmodule.xml，添加retire-kabse

<kmodule xmlns="http://www.drools.org/xsd/kmodule">
    <!--
        kbase 可以存在多个
        name: 指定kbase的名字，需要是唯一的
        packages: 包名，可以理解为到src/main/resources目录下查找这个包名下的规则文件,多个包使用逗号分割
        default: 当前kbase是否是默认的kbase
    -->
    <kbase name="shop-kabse" packages="com.example.shop" default="false">
        <!--
            ksession 可以存在多个
            name: 指定ksession 的名字，需要唯一
            defalut: 当前ksession在这个kbase下是否是默认的
            type: 指定当前ksession是否是有状态的 stateless表示是无状态的
        -->
        <ksession name="shop-ksession" default="false" type="stateless"/>
        <ksession name="shop-ksession-stateful" default="false" type="stateful"/>
    </kbase>
    <kbase name="retire-kabse" packages="com.example.retire" default="false">
        <ksession name="retire-ksession" default="false" type="stateless"/>
        <ksession name="retire-ksession-stateful" default="false" type="stateful"/>
    </kbase>
</kmodule>

• 添加Person待处理对象

package com.example;

public class Person {
    private String name;
    private Integer age;
    private Boolean hasMine;

    private Boolean retire;

    public Person() {
    }

    public Person(String name, Integer age, Boolean hasMine) {
        this.name = name;
        this.age = age;
        this.hasMine = hasMine;
    }

    public Boolean getRetire() {
        return retire;
    }

    public void setRetire(Boolean retire) {
        this.retire = retire;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Boolean getHasMine() {
        return hasMine;
    }

    public void setHasMine(Boolean hasMine) {
        this.hasMine = hasMine;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", hasMine=" + hasMine +
                ", retire=" + retire +
                '}';
    }
}

• 调用规则例子

    private static void handlePersonTest(){
        // 获取kie services
        KieServices kieServices = KieServices.get();
        // 获取kie容器对象
        KieContainer kieContainer = kieServices.getKieClasspathContainer();
        // 获取kie session , 此处获取的是有状态的session
        KieSession kieSession = kieContainer.newKieSession("retire-ksession-stateful");

        List<Person> persons = Arrays.asList(
                new Person("张三",25,true),
                new Person("李四",62,false),
                new Person("李四",66,false)
                );;
                
        // 添加监听器，便于观察日志
        kieSession.addEventListener(new DebugRuleRuntimeEventListener());
        // 将读取的数据插入到规则引擎中
        for (Person person : persons) {
            kieSession.insert(person);
        }

        // 触发所有的规则，如果只想触发指定的规则，则使用fireAllRules(AgendaFilter agendaFilter)方法
        kieSession.fireAllRules();

        // 有状态的session一定需要调用dispose方法
        kieSession.dispose();
        for (Person person : persons) {
            System.err.println(person.toString());
        }
        
    }

• 执行日志

10:56:46.502 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Found kmodule: file:/E:/nick/drools/my-project/target/classes/META-INF/kmodule.xml
10:56:46.505 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - KieModule URL type=file url=/E:/nick/drools/my-project/target/classes
10:56:46.653 [main] WARN org.drools.compiler.kie.builder.impl.ClasspathKieProject - Unable to find pom.properties in /E:/nick/drools/my-project/target/classes
10:56:46.656 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Recursed up folders, found and used pom.xml E:\nick\drools\my-project\pom.xml
10:56:46.657 [main] INFO org.drools.compiler.kie.builder.impl.InternalKieModuleProvider - Creating KieModule for artifact com.example:my-project:1.0-SNAPSHOT
10:56:46.658 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - Discovered classpath module com.example:my-project:1.0-SNAPSHOT
10:56:46.659 [main] DEBUG org.drools.compiler.kie.builder.impl.KieRepositoryImpl - KieModule was added: FileKieModule[releaseId=com.example:my-project:1.0-SNAPSHOT,file=E:\nick\drools\my-project\target\classes]
10:56:46.660 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - Start creation of KieBase: retire-kabse
10:56:46.669 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
10:56:46.690 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
10:56:46.690 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
10:56:47.034 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - End creation of KieBase: retire-kabse
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:1:992955027:992955027:1:DEFAULT:NON_TRAIT:com.example.Person:Person{name='张三', age=25, hasMine=true, retire=null}], getObject()=Person{name='张三', age=25, hasMine=true, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:1:992955027:992955027:1:DEFAULT:NON_TRAIT:com.example.Person:Person{name='张三', age=25, hasMine=true, retire=null}], originOffset=-1, propagationNumber=2, rule=null, type=INSERTION]]
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:2:1092822:1092822:2:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=62, hasMine=false, retire=null}], getObject()=Person{name='李四', age=62, hasMine=false, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:2:1092822:1092822:2:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=62, hasMine=false, retire=null}], originOffset=-1, propagationNumber=3, rule=null, type=INSERTION]]
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:3:1641931089:1641931089:3:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=66, hasMine=false, retire=null}], getObject()=Person{name='李四', age=66, hasMine=false, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:3:1641931089:1641931089:3:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=66, hasMine=false, retire=null}], originOffset=-1, propagationNumber=4, rule=null, type=INSERTION]]
Person{name='张三', age=25, hasMine=true, retire=true}
Person{name='李四', age=62, hasMine=false, retire=false}
Person{name='李四', age=66, hasMine=false, retire=true}
10:56:47.059 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now FIRING_ALL_RULES
张三：你家里有矿，快快退休
李四：家里穷，再干几年吧
李四：年纪到了，牛都干不动了，退了退了
10:56:47.073 [main] DEBUG org.drools.core.common.DefaultAgenda - State was FIRING_ALL_RULES is now HALTING
10:56:47.073 [main] DEBUG org.drools.core.common.DefaultAgenda - State was HALTING is now INACTIVE
10:56:47.073 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now DISPOSED

Process finished with exit code 0

全集变量

前面一个版本，实现退休年龄是写死的，如果想要作一个参数传入，则做如下修改：

• 添加规则文件com/example/retire1/retire-rules.drl

// 包名，必须防止到第一行，这个名字需要和 kbase中package属性的值一致
package com.example.retire1;

/**
 * 导入类
 */
import com.example.Person;


global com.example.MyGlobalObject myGlobalObject;



//定义全局参数
//global Integer count; //定义一个包装类型的全局变量


// 定义规则
rule "retire1-rule-01"
    when
        // 模式匹配：到工作内存中查找Person，并且这个对象的家里需要有矿
        // 如果条件成立，$person，一般以$开头，和fact对象区分开
        $person:Person(hasMine == true)
    then
        System.out.println($person.getName()+"：你家里有矿，快快退休:");
//        System.out.println(count);
        // 赋值，此处赋值后，在Java代码中获取获取到赋值后的值
        $person.setRetire(true);
end

rule "retire1-rule-02"
    when //家里没矿，又小于65岁，那老实工作吧
        $person:Person(hasMine == false, age  < myGlobalObject.getRetireAge() )
    then
        System.out.println($person.getName()+"：家里穷，再干几年吧，还没超过"+myGlobalObject.getRetireAge());
        $person.setRetire(false);
end

rule "retire1-rule-03"
    when //家里没矿，又大于等于65岁，没办法，干不动了，退休吧
       $person:Person(hasMine == false, age  >= myGlobalObject.getRetireAge() )
    then
       System.out.println($person.getName()+"：年纪到了，牛都干不动了，退了退了，超过"+myGlobalObject.getRetireAge());
       $person.setRetire(true);
end

• 添加规则元数据声明META-INF/kmodule.xml

<kmodule xmlns="http://www.drools.org/xsd/kmodule">
    <!--
        kbase 可以存在多个
        name: 指定kbase的名字，需要是唯一的
        packages: 包名，可以理解为到src/main/resources目录下查找这个包名下的规则文件,多个包使用逗号分割
        default: 当前kbase是否是默认的kbase
    -->
    <kbase name="shop-kabse" packages="com.example.shop" default="false">
        <!--
            ksession 可以存在多个
            name: 指定ksession 的名字，需要唯一
            defalut: 当前ksession在这个kbase下是否是默认的
            type: 指定当前ksession是否是有状态的 stateless表示是无状态的
        -->
        <ksession name="shop-ksession" default="false" type="stateless"/>
        <ksession name="shop-ksession-stateful" default="false" type="stateful"/>
    </kbase>
    <kbase name="retire-kabse" packages="com.example.retire" default="false">
        <ksession name="retire-ksession" default="false" type="stateless"/>
        <ksession name="retire-ksession-stateful" default="false" type="stateful"/>
    </kbase>
    <kbase name="retire-kabse1" packages="com.example.retire1" default="false">
        <ksession name="retire-ksession1" default="false" type="stateless"/>
        <ksession name="retire-ksession-stateful1" default="false" type="stateful"/>
    </kbase>
</kmodule>

• 添加全局对象com/example/MyGlobalObject.java

package com.example;

public class MyGlobalObject {
    private Integer retireAge;

    public MyGlobalObject(Integer retireAge) {
        this.retireAge = retireAge;
    }

    public Integer getRetireAge() {
        return retireAge;
    }

    public void setRetireAge(Integer retireAge) {
        this.retireAge = retireAge;
    }
}

• 调用规则例子src/main/java/com/example/App.java

  public static void main(String[] args) {
        handlePersonTest1();
    }

    private static void handlePersonTest1(){
        // 获取kie services
        KieServices kieServices = KieServices.get();
        // 获取kie容器对象
        KieContainer kieContainer = kieServices.getKieClasspathContainer();
        // 获取kie session , 此处获取的是有状态的session
        KieSession kieSession = kieContainer.newKieSession("retire-ksession-stateful1");

        // 定义全局参数
        MyGlobalObject myGlobalObject = new MyGlobalObject(60);

        // 将全局参数插入到规则引擎中
        kieSession.setGlobal("myGlobalObject", myGlobalObject);


        List<Person> persons = Arrays.asList(
                new Person("张三",25,true),
                new Person("李四",55,false),
                new Person("王五",62,false),
                new Person("李麻子",66,false)
        );;

        // 添加监听器，便于观察日志
        kieSession.addEventListener(new DebugRuleRuntimeEventListener());
        // 将读取的数据插入到规则引擎中
        for (Person person : persons) {
            kieSession.insert(person);
        }

        // 触发所有的规则，如果只想触发指定的规则，则使用fireAllRules(AgendaFilter agendaFilter)方法
        kieSession.fireAllRules();

        // 有状态的session一定需要调用dispose方法
        kieSession.dispose();
        for (Person person : persons) {
            System.err.println(person.toString());
        }
    }

• 执行效果日志：

12:00:51.599 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Found kmodule: file:/E:/nick/drools/my-project/target/classes/META-INF/kmodule.xml
12:00:51.602 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - KieModule URL type=file url=/E:/nick/drools/my-project/target/classes
12:00:51.755 [main] WARN org.drools.compiler.kie.builder.impl.ClasspathKieProject - Unable to find pom.properties in /E:/nick/drools/my-project/target/classes
12:00:51.758 [main] INFO org.drools.compiler.kie.builder.impl.ClasspathKieProject - Recursed up folders, found and used pom.xml E:\nick\drools\my-project\pom.xml
12:00:51.758 [main] INFO org.drools.compiler.kie.builder.impl.InternalKieModuleProvider - Creating KieModule for artifact com.example:my-project:1.0-SNAPSHOT
12:00:51.759 [main] DEBUG org.drools.compiler.kie.builder.impl.ClasspathKieProject - Discovered classpath module com.example:my-project:1.0-SNAPSHOT
12:00:51.761 [main] DEBUG org.drools.compiler.kie.builder.impl.KieRepositoryImpl - KieModule was added: FileKieModule[releaseId=com.example:my-project:1.0-SNAPSHOT,file=E:\nick\drools\my-project\target\classes]
12:00:51.762 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - Start creation of KieBase: retire-kabse1
12:00:51.771 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
12:00:51.791 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
12:00:51.791 [main] DEBUG org.drools.compiler.compiler.JavaDialectConfiguration - Selected compiler ECLIPSE [drools.dialect.java.compiler:null, hasEclipseCompiler:true]
12:00:52.145 [main] INFO org.drools.compiler.kie.builder.impl.KieContainerImpl - End creation of KieBase: retire-kabse1
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:1:1833343025:1833343025:1:DEFAULT:NON_TRAIT:com.example.Person:Person{name='张三', age=25, hasMine=true, retire=null}], getObject()=Person{name='张三', age=25, hasMine=true, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:1:1833343025:1833343025:1:DEFAULT:NON_TRAIT:com.example.Person:Person{name='张三', age=25, hasMine=true, retire=null}], originOffset=-1, propagationNumber=2, rule=null, type=INSERTION]]
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:2:1022830989:1022830989:2:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=55, hasMine=false, retire=null}], getObject()=Person{name='李四', age=55, hasMine=false, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:2:1022830989:1022830989:2:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李四', age=55, hasMine=false, retire=null}], originOffset=-1, propagationNumber=3, rule=null, type=INSERTION]]
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:3:33510911:33510911:3:DEFAULT:NON_TRAIT:com.example.Person:Person{name='王五', age=62, hasMine=false, retire=null}], getObject()=Person{name='王五', age=62, hasMine=false, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:3:33510911:33510911:3:DEFAULT:NON_TRAIT:com.example.Person:Person{name='王五', age=62, hasMine=false, retire=null}], originOffset=-1, propagationNumber=4, rule=null, type=INSERTION]]
==>[ObjectInsertedEventImpl: getFactHandle()=[fact 0:4:891232836:891232836:4:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李麻子', age=66, hasMine=false, retire=null}], getObject()=Person{name='李麻子', age=66, hasMine=false, retire=null}, getKnowledgeRuntime()=KieSession[0], getPropagationContext()=PhreakPropagationContext [entryPoint=EntryPoint::DEFAULT, factHandle=[fact 0:4:891232836:891232836:4:DEFAULT:NON_TRAIT:com.example.Person:Person{name='李麻子', age=66, hasMine=false, retire=null}], originOffset=-1, propagationNumber=5, rule=null, type=INSERTION]]
12:00:52.171 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now FIRING_ALL_RULES
张三：你家里有矿，快快退休:
李四：家里穷，再干几年吧，还没超过60
王五：年纪到了，牛都干不动了，退了退了，超过60
李麻子：年纪到了，牛都干不动了，退了退了，超过60
12:00:52.186 [main] DEBUG org.drools.core.common.DefaultAgenda - State was FIRING_ALL_RULES is now HALTING
12:00:52.186 [main] DEBUG org.drools.core.common.DefaultAgenda - State was HALTING is now INACTIVE
12:00:52.186 [main] DEBUG org.drools.core.common.DefaultAgenda - State was INACTIVE is now DISPOSED
Person{name='张三', age=25, hasMine=true, retire=true}
Person{name='李四', age=55, hasMine=false, retire=false}
Person{name='王五', age=62, hasMine=false, retire=true}
Person{name='李麻子', age=66, hasMine=false, retire=true}

Process finished with exit code 0