默认上easy-rules 的数据是没有返回值的，同时对于基于yaml 配置方式更是如此，官方给予我们了一种解决方法
就是基于pojo添加返回字段，但是基于yaml 配置的方式就不方便了，实际上我们可以通过组合的模式——添加一个
最总解决的rule（使用pojo）同时配置一个比较大的优先级，同时这个rule，永远都是执行的就可以解决了，以下是
一个实践
项目结构
详细的可以参考https://www.cnblogs.com/rongfengliang/p/12686702.html
- pom.xml
<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.dalong</groupId>
<artifactId>myruleapps</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<encoding>UTF-8</encoding>
<java.version>1.8</java.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>
</build>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>org.jeasy</groupId>
<artifactId>easy-rules-core</artifactId>
<version>3.4.0</version>
</dependency>
<dependency>
<groupId>org.jeasy</groupId>
<artifactId>easy-rules-mvel</artifactId>
<version>3.4.0</version>
</dependency>
<dependency>
<groupId>org.jeasy</groupId>
<artifactId>easy-rules-spel</artifactId>
<version>3.4.0</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.25</version>
</dependency>
</dependencies>
</project>
- yaml规则
---
name: "1"
description: "1"
condition: "user.getAge()>26"
priority: 1
actions:
- "user.age=user.age-2;System.out.println(user.userinfo);"
---
name: "2"
description: "2"
condition: "user.getAge()<26"
priority: 2
actions:
- "UserService.doAction1(user)"
---
name: "3"
description: "3"
condition: "user.name.length<10"
priority: 3
actions:
- "UserService.doAction2(user)"
---
name: "4"
description: "4"
condition: "user.name.length<40"
priority: 4
actions:
- "System.out.println("rule4 "+user.userinfo)"
---
name: "5"
description: "5"
condition: "user.name.length<30"
priority: 5
actions:
- "UserService.doAction4(user.userinfo)"
---
name: "6"
description: "6"
condition: "user.name.length<30"
priority: 6
actions:
- "System.out.println("rule6 "+user.userinfo)"
---
name: "7"
description: "7"
condition: "user.name.length<30"
priority: 7
actions:
- "UserService.doAction4(user)"
---
name: "8"
description: "8"
condition: "user.name.length<30"
priority: 8
actions:
- "System.out.println("rule8 "+user)"
- 最后必须执行的rule
MyRule.java 优先级数字很大，最后执行
package com.dalong;
import org.jeasy.rules.annotation.Action;
import org.jeasy.rules.annotation.Condition;
import org.jeasy.rules.annotation.Fact;
import org.jeasy.rules.annotation.Rule;
import org.jeasy.rules.api.Facts;
@Rule(name = "100", description = "my rule description", priority = 100)
public class MyRule<T> {
private boolean executed;
private T result;
@Condition
public boolean when(@Fact("user") T fact) {
//my rule conditions
return true;
}
@Action(order = 1)
public void then(@Fact("user") T facts) throws Exception {
try {
System.out.println("my rule has been executed");
result = (T)facts; // assign your result here
executed = true;
} catch (Exception e) {
// executed flag will remain false if an exception occurs
throw e;
}
}
public boolean isExecuted() {
return executed;
}
public T getResult() {
return result;
}
}
代码集成
- 入口
package com.dalong;
import org.jeasy.rules.api.*;
import org.jeasy.rules.core.DefaultRulesEngine;
import org.jeasy.rules.core.InferenceRulesEngine;
import org.jeasy.rules.core.RuleBuilder;
import org.jeasy.rules.mvel.MVELRuleFactory;
import org.jeasy.rules.support.YamlRuleDefinitionReader;
import org.mvel2.ParserContext;
import java.io.FileReader;
import java.util.HashMap;
import java.util.Map;
import static com.dalong.DecreaseTemperatureAction.decreaseTemperature;
import static com.dalong.HighTemperatureCondition.itIsHot;
import static com.dalong.AppendUserName.appendUserName;
import static com.dalong.NameTooShort.nameTooShort;
public class Launcher {
public static void main(String[] args) throws Exception {
app3();
}
private static void app3() throws Exception {
MVELRuleFactory ruleFactory = new MVELRuleFactory(new YamlRuleDefinitionReader());
ParserContext context =new ParserContext();
context.addImport("UserService", UserService.class);
Rules yamlRules = ruleFactory.createRules(new FileReader(Launcher.class.getClassLoader().getResource("rules.yml").getFile()),context);
DefaultRulesEngine rulesEngine = new DefaultRulesEngine();
Facts facts = new Facts();
// 此规则理论上应该走执行的
MyRule<User> rule = new MyRule<User>();
Map<Object,Object> userinfo = new HashMap<>();
userinfo.put("name2","dalong");
userinfo.put("age2",27);
yamlRules.register(rule);
User user =new User("dalong",27);
user.setUserinfo(userinfo);
facts.put("user",user);
rulesEngine.registerRuleListener(new MyRulesListener());
rulesEngine.registerRulesEngineListener(new MyRuleEngineListener());
rulesEngine.fire(yamlRules, facts);
// 规则执行完成之后，获取最后的结果
if(rule.isExecuted()){
User userResult= rule.getResult();
System.out.println("result from final ruls"+userResult.toString());
}
}
}
说明
以及上参考资料的一个实践，实际中还是有点用的
参考资料
https://github.com/j-easy/easy-rules/wiki/faqs
https://www.cnblogs.com/rongfengliang/p/12686702.html