Java 将新规则文件添加到现有知识会话

我想在运行时向现有的

KieSession

动态添加新的规则文件（或修改现有的规则文件）

我找到了一个与此相关的解决方案，并尝试了其中提到的解决方案，但出现了运行时异常

使用的代码如下：

Driver.java

：

package app1;

import java.io.FileInputStream;
import java.io.FileNotFoundException;

import org.kie.api.KieBase;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.Message;
import org.kie.api.builder.ReleaseId;
import org.kie.api.builder.Results;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;

public class Driver {

  public static final void main(String[] args) {
    try {
      KieServices kieServices = KieServices.Factory.get();
      KieFileSystem kfs = kieServices.newKieFileSystem();

      String ruleFilePath = "src/main/resources/rules/ruleFile1.drl";
      FileInputStream fis = null;
      try {
        fis = new FileInputStream(ruleFilePath);
      } catch (FileNotFoundException e) {
        e.printStackTrace();
      }
      kfs = kfs.write(ruleFilePath, kieServices.getResources().newInputStreamResource(fis));

      KieBuilder kieBuilder = kieServices.newKieBuilder(kfs).buildAll();
      Results results = kieBuilder.getResults();
      if (results.hasMessages(Message.Level.ERROR)) {
        System.out.println("~~ERROR~~:");
        System.out.println(results.getMessages());
        throw new IllegalStateException("### errors ###");
      }

      ReleaseId releaseId1 = kieServices.newReleaseId("org.default", "artifact", "1.0.0-SNAPSHOT");
      KieContainer kieContainer = kieServices.newKieContainer(releaseId1);
      KieBase kieBase = kieContainer.newKieBase(kieServices.newKieBaseConfiguration());

      KieSession kSession = kieBase.newKieSession();
      String s = "hello";
      kSession.insert(s);
      kSession.fireAllRules();

      // I edit the rule file manually at this point.
      System.out.println("Waiting");
      Thread.sleep(5000);

      ReleaseId releaseId2 = kieServices.newReleaseId("org.default", "artifact", "1.0.1-SNAPSHOT");
      kieContainer.updateToVersion(releaseId2);
      kSession.fireAllRules();

      System.out.println("Bye");
    } catch (Throwable t) {
      t.printStackTrace();
    }
  }
}

package app1;

rule "rule1"
when
    s: String()
then
    System.out.println("In rule - " + drools.getRule().getName());
    System.out.println("s = " + s);
end

规则文件1.drl

：

package app1;

import java.io.FileInputStream;
import java.io.FileNotFoundException;

import org.kie.api.KieBase;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.Message;
import org.kie.api.builder.ReleaseId;
import org.kie.api.builder.Results;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;

public class Driver {

  public static final void main(String[] args) {
    try {
      KieServices kieServices = KieServices.Factory.get();
      KieFileSystem kfs = kieServices.newKieFileSystem();

      String ruleFilePath = "src/main/resources/rules/ruleFile1.drl";
      FileInputStream fis = null;
      try {
        fis = new FileInputStream(ruleFilePath);
      } catch (FileNotFoundException e) {
        e.printStackTrace();
      }
      kfs = kfs.write(ruleFilePath, kieServices.getResources().newInputStreamResource(fis));

      KieBuilder kieBuilder = kieServices.newKieBuilder(kfs).buildAll();
      Results results = kieBuilder.getResults();
      if (results.hasMessages(Message.Level.ERROR)) {
        System.out.println("~~ERROR~~:");
        System.out.println(results.getMessages());
        throw new IllegalStateException("### errors ###");
      }

      ReleaseId releaseId1 = kieServices.newReleaseId("org.default", "artifact", "1.0.0-SNAPSHOT");
      KieContainer kieContainer = kieServices.newKieContainer(releaseId1);
      KieBase kieBase = kieContainer.newKieBase(kieServices.newKieBaseConfiguration());

      KieSession kSession = kieBase.newKieSession();
      String s = "hello";
      kSession.insert(s);
      kSession.fireAllRules();

      // I edit the rule file manually at this point.
      System.out.println("Waiting");
      Thread.sleep(5000);

      ReleaseId releaseId2 = kieServices.newReleaseId("org.default", "artifact", "1.0.1-SNAPSHOT");
      kieContainer.updateToVersion(releaseId2);
      kSession.fireAllRules();

      System.out.println("Bye");
    } catch (Throwable t) {
      t.printStackTrace();
    }
  }
}

package app1;

rule "rule1"
when
    s: String()
then
    System.out.println("In rule - " + drools.getRule().getName());
    System.out.println("s = " + s);
end

我得到的输出是：

In rule - rule1
s = hello
Waiting
java.lang.NullPointerException
  at org.drools.compiler.kie.util.ChangeSetBuilder.build(ChangeSetBuilder.java:53)
  at org.drools.compiler.kie.builder.impl.KieContainerImpl.update(KieContainerImpl.java:129)
  at org.drools.compiler.kie.builder.impl.KieContainerImpl.updateToVersion(KieContainerImpl.java:106)
  at app1.Driver.main(Driver.java:54)

我还阅读并注意到，它使用了一些类似这样的代码来动态地将新规则文件添加到

KieSession

：

KnowledgeBase kbase = SerializationHelper.serializeObject( loadKnowledgeBase( "test_Dynamic1.drl" ) );
Collection<KnowledgePackage> kpkgs = SerializationHelper.serializeObject( loadKnowledgePackages( "test_Dynamic2.drl" ) );
kbase.addKnowledgePackages(kpkgs);

KnowledgeBase kbase=SerializationHelper.serializeObject（loadKnowledgeBase（“test_Dynamic1.drl”）；
集合kpkgs=SerializationHelper.serializeObject（loadKnowledgePackages（“test_Dynamic2.drl”）；
kbase.addKnowledgePackages（kpkg）；

但问题是

KnowledgeBase

是一个内部API，不向最终用户公开

我正在使用Drools 6.2.0。

编辑：

我发现也许

KieScanner

可以用来实现我想要的。 但是我找不到一个合适的例子来描述如何使用

KieScanner

来添加新的规则文件或替换现有的规则文件

---

包含一些有用的信息，但我无法正确理解。另外，我更喜欢内存罐。

我一直怀疑w.r.t.通过添加规则并运行从该规则库派生的会话来动态更改规则库。当WM中存在触发新规则的事实时，这意味着什么？这些新规则修改了事实，从而触发了旧规则，而几秒钟后它们还没有被触发？（我想你知道我的意思。）--如果WM为空，请处理该会话并启动一个新会话。-如果WM不是空的，那要看情况而定，我不会在没有具体应用分析的情况下提出任何建议。