drools in java_drools 编程例子

关于 Drools 更多的介绍 可以参考之前的文章。

这篇文章主要讲解如何在项目中执行 DRL 文件并取得结果。

ERROR

如果遇到这样的错误，大部分情况下是 drl 规则文件所在的文件夹，没有被项目识别为 resources 文件夹，在 IntelliJ IDE 中可以使用设置为资源文件夹来解决。

Exception in thread "main" java.lang.RuntimeException: Unable to get LastModified for ClasspathResource

at org.drools.core.io.impl.ClassPathResource.getLastModified(ClassPathResource.java:212)

at org.drools.core.io.impl.ClassPathResource.getInputStream(ClassPathResource.java:149)

at org.drools.compiler.compiler.DrlParser.parse(DrlParser.java:154)

at org.drools.compiler.compiler.DrlParser.parse(DrlParser.java:144)

at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.drlToPackageDescr(KnowledgeBuilderImpl.java:541)

at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.addPackageFromDrl(KnowledgeBuilderImpl.java:529)

at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.addKnowledgeResource(KnowledgeBuilderImpl.java:753)

at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:2296)

at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:2285)

at com.neo.drools.banking.RuleRunner.runRules(RuleRunner.java:32)

at com.neo.drools.banking.BankingExample1.main(BankingExample1.java:10)

Caused by: java.io.FileNotFoundException: 'Example1.drl' cannot be opened because it does not exist

at org.drools.core.io.impl.ClassPathResource.getURL(ClassPathResource.java:173)

at org.drools.core.io.impl.ClassPathResource.getLastModified(ClassPathResource.java:185)

... 10 more