无法在Eclipse中运行"Hello World"Drools示例:运行时异常org.drools.RuntimeDroolsException:无法加载方言

Question

我刚安装了Drools plug-inEclipse(版本3.5.2),我正在尝试运行插件附带的"Hello World"示例.

当我运行代码时,我得到runtime error以下堆栈跟踪:

org.drools.RuntimeDroolsException: Unable to load dialect 'org.drools.rule.builder.dialect.java.JavaDialectConfiguration:java:org.drools.rule.builder.dialect.java.JavaDialectConfiguration'
 at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:274)
 at org.drools.compiler.PackageBuilderConfiguration.buildDialectConfigurationMap(PackageBuilderConfiguration.java:259)
 at org.drools.compiler.PackageBuilderConfiguration.init(PackageBuilderConfiguration.java:176)
 at org.drools.compiler.PackageBuilderConfiguration.<init>(PackageBuilderConfiguration.java:153)
 at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:242)
 at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:142)
 at org.drools.builder.impl.KnowledgeBuilderProviderImpl.newKnowledgeBuilder(KnowledgeBuilderProviderImpl.java:29)
 at org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilder(KnowledgeBuilderFactory.java:29)
 at com.sample.DroolsTest.readKnowledgeBase(DroolsTest.java:39)
 at com.sample.DroolsTest.main(DroolsTest.java:23)
Caused by: java.lang.RuntimeException: **The Eclipse JDT Core jar is not in the classpath**
 at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.setCompiler(JavaDialectConfiguration.java:94)
 at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.init(JavaDialectConfiguration.java:55)
 at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:270)
 ... 9 more

以下是一些相关的Java代码:

public static final void main(String[] args) {
    try {
        // load up the knowledge base
        KnowledgeBase kbase = readKnowledgeBase();
    }
}

private static KnowledgeBase readKnowledgeBase() throws Exception {
    KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
    kbuilder.add(ResourceFactory.newClassPathResource("Sample.drl"), ResourceType.DRL);
    KnowledgeBuilderErrors errors = kbuilder.getErrors();
    if (errors.size() > 0) {
        for (KnowledgeBuilderError error : errors) {
            System.err.println(error);
        }
        throw new IllegalArgumentException("Could not parse knowledge.");
    }
    KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
    kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
    return kbase;
}

Answer 1

您在类路径中缺少eclipse JDT核心jar.如果您没有使用Drools类路径容器,或者您手动创建了自己的运行时,请确保jar是类路径或运行时目录的一部分.如果您正在使用Drools类路径容器并生成默认运行时,并且JDT核心jar不存在,请确保使用支持Eclipse 3.5.2的最新版本的插件.您当然也可以手动添加JDT核心jar并重新创建运行时.

有关运行时的更多信息,请访问http://download.jboss.org/drools/release/5.1.1.34858.FINAL/drools-5.1.1-docs.zip并打开drools-5.1.1-docs.zip\drools-flow\html\ch.Drools_Eclipse_IDE_Features.html