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Drools executes string rules or executes a rule file

2022-07-02 12:14:00 【huan_ one thousand nine hundred and ninety-three】

1、 background

Here we mainly record 2 A small knowledge point , Prevent forgetting later .

1、 How to be in drools Execute a drl file .
2、 If our rule is a String String of type , So how to implement .

2、 Realization

2.1 Execute specified drl file

KieHelper kieHelper = new KieHelper();
//  Get the specified drl file 
Resource resource = ResourceFactory.newClassPathResource("rules/alway-rule.drl", "UTF-8");
kieHelper.addResource(resource,ResourceType.DRL);
KieBase kieBase = kieHelper.build();
KieSession kieSession = kieBase.newKieSession();
kieSession.fireAllRules();
kieSession.dispose();

2.2 perform String The rules

String drl = "package rules\n" +
                "\n" +
                "rule \"rule-01\"\n" +
                " when\n" +
                " $i: Integer()\n" +
                " then \n" +
                " System.out.println(\" The rules :[\"+drools.getRule().getName()+\"] perform , The value existing in the rule memory is :\"+$i);\n" +
                "end";


KieHelper kieHelper = new KieHelper();
kieHelper.addContent(drl, ResourceType.DRL);
//  establish KieBase It's a costly one 
KieBase kieBase = kieHelper.build(EqualityBehaviorOption.IDENTITY);
System.out.println(kieBase);
//  establish KieSession The cost is small 

KieSession kieSession = kieBase.newKieSession();

kieSession.insert(123);
kieSession.fireAllRules();

kieBase.removeRule("rules", "rule-01");

kieSession.insert(456);
kieSession.fireAllRules();

kieSession.dispose();