[bigdata-092] 一个java的drools app

1. 文档来源

从drools官方demo改编而来

2. eclipse要先安装drools的第三方开发工具

3. 用eclipse-->new-->project..->drools--> drools project创建一个新的空项目

3. 源码目录结构

├── pom.xml
├── src
│ ? └── main
│ ? ? ? ├── java
│ ? ? ? │ ? └── com
│ ? ? ? │ ? ? ? └── ttz
│ ? ? ? │ ? ? ? ? ? └── demo
│ ? ? ? │ ? ? ? ? ? ? ? ├── Main.java
│ ? ? ? │ ? ? ? ? ? ? ? └── Message.java
│ ? ? ? └── resources
│ ? ? ? ? ? ├── dtables
│ ? ? ? ? ? ├── META-INF
│ ? ? ? ? ? │ ? ├── kmodule.xml
│ ? ? ? ? ? │ ? └── maven
│ ? ? ? ? ? │ ? ? ? └── pom.properties
│ ? ? ? ? ? ├── process
│ ? ? ? ? ? └── rules
│ ? ? ? ? ? ? ? ├── Sample2.drl
│ ? ? ? ? ? ? ? └── Sample.drl

4. pom.xml内容如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

  <modelVersion>4.0.0</modelVersion>

  <groupId>com.ttz</groupId>
  <artifactId>mydroolsexample</artifactId>
  <version>1.0.0-SNAPSHOT</version>

  <name>Drools :: Sample Maven Project</name>
  <description>A sample Drools Maven project</description>

  <properties>
    <runtime.version>6.4.0.Final</runtime.version>
  </properties>

  <repositories>
    <repository>
      <id>jboss-public-repository-group</id>
      <name>JBoss Public Repository Group</name>
      <url>http://repository.jboss.org/nexus/content/groups/public/</url>
      <releases>
        <enabled>true</enabled>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>true</enabled>
        <updatePolicy>daily</updatePolicy>
      </snapshots>
    </repository>
  </repositories>

  <dependencies>
    <dependency>
      <groupId>org.kie</groupId>
      <artifactId>kie-api</artifactId>
      <version>${runtime.version}</version>
    </dependency>
    <dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-core</artifactId>
      <version>${runtime.version}</version>
    </dependency>
    <dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-decisiontables</artifactId>
      <version>${runtime.version}</version>
    </dependency>

    <dependency>
      <groupId>org.jbpm</groupId>
      <artifactId>jbpm-test</artifactId>
      <version>${runtime.version}</version>
    </dependency>
  </dependencies>
</project>

5. Main.jav内容如下：

package com.ttz.demo;

import org.kie.api.KieServices;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;

import com.ttz.demo.Message;

public class Main {

	public static void main(String[] args) {
		KieServices ks = KieServices.Factory.get();
	    KieContainer kContainer = ks.getKieClasspathContainer();
    	KieSession kSession = kContainer.newKieSession("ksession-rules");

    	Message message = new Message();
        message.setMessage("Hello World 2");
        message.setStatus(Message.HELLO);
        kSession.insert(message);
        kSession.fireAllRules();
	}
	
}

6. Message.java内容如下

package com.ttz.demo;

public class Message {
	public static final int HELLO = 0;
    public static final int GOODBYE = 1;

    private String message;

    private int status;

	public String getMessage() {
		return message;
	}

	public void setMessage(String message) {
		this.message = message;
	}

	public int getStatus() {
		return status;
	}

	public void setStatus(int status) {
		this.status = status;
	}



}

7.?Sample.drl文件内容如下

package com.ttz.demo
 
import com.ttz.demo.Message;
 
rule "Hello World"
    when
        m : Message( status == Message.HELLO,myMessage : message )
    then
        //System.out.println( myMessage );
        //m.setMessage( "THis is my hello world" );
        //m.setStatus( Message.GOODBYE );
        //update( m );
        System.out.print("hello wroldn");
end

rule "GoodBye"
    when
        Message( status == Message.GOODBYE,myMessage : message )
    then
        System.out.println( myMessage );
end

8. Sample2.drl文件内容如下

package com.ttz.demo
 
import com.ttz.demo.Message;
 
rule "Hello World 2"
    when
        m : Message( status == Message.HELLO,myMessage : message )
    then
        System.out.println("hello world 2n");
        //System.out.println( myMessage );
        //m.setMessage( "THis is my hello world 2" );
        //m.setStatus( Message.GOODBYE );
        //update( m );
end

rule "GoodBye 2"
    when
        Message( status == Message.GOODBYE,myMessage : message )
    then
        System.out.println( myMessage );
end

9. 其他文件都是自动生成的，不需要修改。

10. 运行，则输出结果是

hello wrold
hello world 2

表明对同一个Fact，两条规则都生效了。

同理，其实也可以设置更多的Fact，更多的规则。