Spring Boot 中使用 Drools 规则引擎的完整步骤

 <!-- drools规则引擎 -->
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-compiler</artifactId>
            <version>7.6.0.Final</version>
        </dependency>

package com.song;
import com.song.rulesobj.Customer
rule "ORDINARY-Customers"
when
    customer: Customer(type == "ORDINARY")
then
    customer.setDiscount(0.9*customer.getOriginalPrice()); // 9折  普通会员
end
rule "VIP-Customers"
when
    customer: Customer(type == "VIP")
then
    customer.setDiscount(0.6*customer.getOriginalPrice()); // 6折 VIP会员
end
rule "SVIP-Customers"
when
    customer: Customer(type == "SVIP")
then
    customer.setDiscount(0.4*customer.getOriginalPrice()); // 4折 SVIP会员
end

package com.song.rulesobj;
import lombok.Data;
@Data
public class Customer {
    /**
     * 客户类型
     */
    private String type;
    /**
     * 客户订单价格
     */
    private Double  originalPrice; // 订单原始价格，即优惠前的价格
    /**
     * 优惠后最终结算价格
     */
    private Double discount;
}

package com.song.conf;
import com.song.bean.DiscountBean;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.KieRepository;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class DroolsConfig {
    @Bean
    public KieContainer kieContainer() {
        KieServices kieServices = KieServices.Factory.get();
        KieRepository kieRepository = kieServices.getRepository();
        KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
        kieFileSystem.write(kieServices.getResources().newClassPathResource("rules/sample.drl"));
        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem);
        kieBuilder.buildAll();
        return kieServices.newKieContainer(kieRepository.getDefaultReleaseId());
    }
    @Bean
    public KieSession kieSession() {
        return kieContainer().newKieSession();
    }
    @Bean
    public DiscountBean discountBean() {
       return new  DiscountBean(kieSession());
    }
}

/*******************************************************************************
 * Package: com.song.bean
 * Type:    DiscountService
 * Date:    2024-06-28 13:45
 *
 * Copyright (c) 2024 LTD All Rights Reserved.
 *
 * You may not use this file except in compliance with the License.
 *******************************************************************************/
package com.song.bean;
import com.song.rulesobj.Customer;
import org.kie.api.runtime.KieSession;
/**
 * 功能描述： 规则处理器封装
 *
 * @author Songxianyang
 * @date 2024-06-28 13:45
 */
public class DiscountBean {
    private KieSession kieSession;
    public DiscountBean(KieSession kieSession) {
        this.kieSession = kieSession;
    }
    public void applyDiscount(Customer customer) {
        kieSession.insert(customer); // 插入客户对象到规则引擎中
        kieSession.fireAllRules(); // 执行规则
        // 客户对象已经被更新，包含了计算出的折扣
        System.out.println("客户订单价格"+customer.getOriginalPrice()+"客户折扣类型: " + customer.getType() + ", 优惠后最终结算价格: " + customer.getDiscount());
    }
}

package com.song.web;
import com.song.bean.DiscountBean;
import com.song.common.annotation.ResponseInfoSkin;
import com.song.rulesobj.Customer;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
@RestController
@Api(tags = "规则引擎")
@ResponseInfoSkin
public class DemoController {
    @Autowired
    private DiscountBean discountBean;
    @PostMapping("/discount")
    @ApiOperation("打折")
    public Double discount(@RequestBody Customer customer) {
        // 规则处理器封装
        discountBean.applyDiscount(customer);
        return customer.getDiscount();
    }
}