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如何用Spring Boot集成Drools

小樊
99
2024-08-29 13:06:27
栏目: 编程语言

要在Spring Boot项目中集成Drools,你需要遵循以下步骤:

  1. 添加依赖

在你的pom.xml文件中,添加以下依赖:

    <!-- Spring Boot Starters -->
   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter</artifactId>
    </dependency>

    <!-- Drools Dependencies -->
   <dependency>
       <groupId>org.drools</groupId>
       <artifactId>drools-compiler</artifactId>
       <version>${drools.version}</version>
    </dependency>
   <dependency>
       <groupId>org.drools</groupId>
       <artifactId>drools-decisiontables</artifactId>
       <version>${drools.version}</version>
    </dependency>
   <dependency>
       <groupId>org.kie</groupId>
       <artifactId>kie-api</artifactId>
       <version>${drools.version}</version>
    </dependency>
   <dependency>
       <groupId>org.kie</groupId>
       <artifactId>kie-internal</artifactId>
       <version>${drools.version}</version>
    </dependency>
   <dependency>
       <groupId>org.kie.modules</groupId>
       <artifactId>org-drools-module</artifactId>
       <version>${drools.version}</version>
    </dependency>
</dependencies>

${drools.version}替换为你想使用的Drools版本,例如7.60.0.Final

  1. 创建KieContainer

创建一个配置类,用于初始化KieContainer。这个类将负责加载和管理你的Drools规则。

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.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();

        // 从类路径加载规则文件
        kieFileSystem.write(kieServices.getResources().newClassPathResource("rules/sample-rule.drl"));

        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem);
        kieBuilder.buildAll();

        return kieServices.newKieContainer(kieRepository.getDefaultReleaseId());
    }
}
  1. 编写规则文件

resources/rules目录下创建一个名为sample-rule.drl的文件,并编写你的Drools规则。例如:

package com.example.drools

import com.example.domain.Person;

rule "Check if person is adult"
when
    $person: Person(age >= 18)
then
    System.out.println("Person is an adult.");
end
  1. 使用KieContainer

现在你可以在你的应用程序中使用KieContainer来执行Drools规则。例如,你可以创建一个服务类来处理规则执行:

import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class DroolsService {

    @Autowired
    private KieContainer kieContainer;

    public void executeRules(Object... facts) {
        KieSession kieSession = kieContainer.newKieSession();
        for (Object fact : facts) {
            kieSession.insert(fact);
        }
        kieSession.fireAllRules();
        kieSession.dispose();
    }
}
  1. 调用服务类

最后,你可以在你的控制器或其他类中调用DroolsService来执行规则。例如:

import com.example.domain.Person;
import com.example.service.DroolsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class SampleController {

    @Autowired
    private DroolsService droolsService;

    @GetMapping("/check-adult")
    public String checkAdult() {
        Person person = new Person();
        person.setAge(20);
        droolsService.executeRules(person);
        return "Checked if person is adult.";
    }
}

现在,当你访问/check-adult端点时,Drools将根据sample-rule.drl中定义的规则检查Person对象是否是成年人。

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