刚开始学drools,有问题想请教一下前辈

[shirley123324]

在执行kbuilder.add(ResourceFactory.newClassPathResource("test.drl"), ResourceType.DRL)时总是报错，同样的代码，在别的目录下可以执行，换个目录就出问题了
下面是异常信息：
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getBeanProperty(ReflectiveAccessorOptimizer.java:690)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getBeanPropertyAO(ReflectiveAccessorOptimizer.java:472)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:374)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:143)
at org.mvel2.optimizers.dynamic.DynamicOptimizer.optimizeAccessor(DynamicOptimizer.java:67)
at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:113)
at org.mvel2.MVEL.executeExpression(MVEL.java:906)
at org.drools.rule.builder.PatternBuilder.getFieldValue(PatternBuilder.java:1382)
at org.drools.rule.builder.PatternBuilder.addConstraintToPattern(PatternBuilder.java:765)
at org.drools.rule.builder.PatternBuilder.addConstraintToPattern(PatternBuilder.java:736)
at org.drools.rule.builder.PatternBuilder.buildRelationalExpression(PatternBuilder.java:721)
at org.drools.rule.builder.PatternBuilder.buildExpression(PatternBuilder.java:673)
at org.drools.rule.builder.PatternBuilder.buildCcdDescr(PatternBuilder.java:657)
at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:629)
at org.drools.rule.builder.PatternBuilder.processConstraintsAndBinds(PatternBuilder.java:477)
at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:302)
at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:123)
at org.drools.rule.builder.GroupElementBuilder.build(GroupElementBuilder.java:67)
at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:84)
at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:2830)
at org.drools.compiler.PackageBuilder.compileRules(PackageBuilder.java:970)
at org.drools.compiler.PackageBuilder.compileAllRules(PackageBuilder.java:879)
at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:871)
at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:466)
at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:694)
at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:51)
at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:40)
at com.example.Test.main(Test.java:25)






还有一个问题是src/main/java这个folder有讲究吗，包和类必须要放src/main/java下面吗？drl文件必须放到src/main/rules下面吗？drl文件有什么讲究，怎么就能找到，怎么就找不到？