Spring Boot

Spring Boot中Drools规则引擎怎么用

小樊
82
2024-08-29 13:08:03
栏目: 编程语言

在 Spring Boot 中使用 Drools 规则引擎主要包括以下几个步骤:

  1. 添加依赖

在你的 pom.xml 文件中添加 Drools 和 Spring Boot 相关的依赖:

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

    <!-- Drools -->
   <dependency>
       <groupId>org.drools</groupId>
       <artifactId>drools-compiler</artifactId>
       <version>7.59.0.Final</version>
    </dependency>
   <dependency>
       <groupId>org.drools</groupId>
       <artifactId>drools-core</artifactId>
       <version>7.59.0.Final</version>
    </dependency>
   <dependency>
       <groupId>org.drools</groupId>
       <artifactId>drools-decisiontables</artifactId>
       <version>7.59.0.Final</version>
    </dependency>
</dependencies>
  1. 创建规则文件

src/main/resources 目录下创建一个名为 rules 的文件夹,然后在该文件夹中创建一个名为 sample.drl 的规则文件。在这个文件中编写你的 Drools 规则:

package com.example.drools

import com.example.drools.domain.Person;

rule "Sample Rule"
when
    $person: Person(age >= 18)
then
    System.out.println("Person is eligible for voting.");
end
  1. 创建实体类

com.example.drools.domain 包下创建一个名为 Person 的实体类:

package com.example.drools.domain;

public class Person {
    private String name;
    private int age;

    // Getters and setters
}
  1. 配置 Drools

创建一个名为 DroolsConfig 的配置类,用于初始化 Drools 的 KieContainer

package com.example.drools.config;

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;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.io.IOException;

@Configuration
public class DroolsConfig {

    @Bean
    public KieContainer kieContainer() throws IOException {
        KieServices kieServices = KieServices.Factory.get();
        KieRepository kieRepository = kieServices.getRepository();
        KieFileSystem kieFileSystem = kieServices.newKieFileSystem();

        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        Resource[] resources = resourcePatternResolver.getResources("classpath*:/rules/*.*");

        for (Resource resource : resources) {
            kieFileSystem.write(resource.getFilename(), resource.getInputStream());
        }

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

        return kieServices.newKieContainer(kieRepository.getDefaultReleaseId());
    }
}
  1. 使用 Drools

在你的服务类中注入 KieContainer,并使用它来执行规则:

package com.example.drools.service;

import com.example.drools.domain.Person;
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(Person person) {
        KieSession kieSession = kieContainer.newKieSession();
        kieSession.insert(person);
        kieSession.fireAllRules();
        kieSession.dispose();
    }
}
  1. 测试

在你的控制器或测试类中调用服务类的 executeRules 方法来测试 Drools 规则引擎:

package com.example.drools.controller;

import com.example.drools.domain.Person;
import com.example.drools.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 DroolsController {

    @Autowired
    private DroolsService droolsService;

    @GetMapping("/test")
    public String test() {
        Person person = new Person();
        person.setName("John Doe");
        person.setAge(20);

        droolsService.executeRules(person);

        return "Rules executed successfully.";
    }
}

现在,当你访问 /test 端点时,Drools 规则引擎将根据定义的规则执行。

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