向应用程序中加入jBPM�l��g

xzc — Tue, 24 Oct 2006 06:18:00 GMT

本文介绍怎样把jBPM�l��g��d��到Web应用�E�序中。所需要用到的资源�Q�可以在jbpm-starters-kit-3.1.2中找到�?/div>

一、首先安装jBPM数据库。jBPM是一个停止状态的�l��g�Q�需要数据库表持久化保存�Q?�Q�业务程序定义和业务�E�序实例及相关的工作��数据。保障工作流引擎的执行�?�Q�异步系�l��用数据库表来模拟消息�pȝ��的功能。需要把消息到数据库表中�Q�由消息�pȝ��的命令执行器异步查询和执行。不像专业的消息�pȝ��那样是远�E�的。它仅仅使用数据库模拟消息系�l��?/div>

1�Q�打开MySQL的命令执行工具Query Browser�?/div>

2�Q�当前选定应用�E�序的数据库�Q�如wcms�?/div>

3�Q�导入脚本文�Ӟ��mysql.drop.create.sql

4�Q�执行该脚本。会在当前数据库中增加jBPM的数据库表�?/div>

二、导入jBPM所需�?jar文�g

1�Q�jbpmlib目录中包含了jBPM所需的全部jar包。包括MySQL的jdbc包�?/div>

2�Q�把它整个复制到应用�E�序的lib目录下�?/div>

3�Q�应用程序的构徏器�\径的“�?#8221;中，把这些jar都加�q�来�?/div>

�q�些classpath下的jar包，都会被该Web应用�E�序的类载入器蝲入�?/div>

三、创建config.files和processes目录�Q��ƈ加入classpath的源代码路径

�Q�一�Q�config.files目录的功�?/div>

�q�个目录存放jBPM的各�c�配�|�文件。放在这里（��是classpath��层�Q�的配置文�g会取代jBPM的jar包中各处的配�|�文件�?/div>

�q�里�Q�由于需要��用mysql�Q�而不是内�|�的hsql内存数据库。所以我们提供了一个修改过的配�|�文�Ӟ��hibernate.cfg.xml。这里提供了Hibernate3的配�|��?/div>

hibernate.cfg.xml配置文�g的部分内�?/div>

    org.hibernate.dialect.MySQLInnoDBDialect
    com.mysql.jdbc.Driver
    jdbc:mysql://localhost:3306/wcms
    root
    root

�Q�二�Q�processes目录的功�?/div>

�q�个目录存放process��程定义。如�Q�manageNews\内有3个文件�?/div>

在jBPM应用�E�序导入.par�?xml文�g�?使用相对路径�Q�如�Q�withubCMS/processdefinition.xml�Q�来定位业务�E�序定义资源文�g�?/div>

怎样把它们放到classpath下，需要根据不同的环境�q�行不同的处理�?/div>

一、一般Java�E�序

1�Q�创建config.files和processes目录�?/div>

2�Q�配�|�构建器路径�Q�将�q?个目录设为到classpath的源代码路径�?/div>

�q�样�Q�运行时�Q�会把它们中的内容复制到classpath目录下�?/div>

二、Eclipse下的Web�E�序

我们使用Eclipse自带的功能发布Web�E�序�?/div>

1�Q�创建config.files和processes目录�?/div>

2�Q�配�|�构建器路径�Q�将�q?个目录设为到classpath的源代码路径�?/div>

3�Q�配�|�classpath,也就�?#8220;�~�省输出文�g�?#8221;�Q��ؓ�Q?/div>

内容��理�Q�应用程序根路径名）/webapps/WEB-INF/classes

4�Q�这��P��在Eclipse�~�译�Ӟ��默认是保存即�~�译�Q�，把这2个文件夹中的内容复制到classpath下�?/div>

5�Q�然后，使用Eclipse自带的功能，发布该Web应用�E�序�?/div>

Eclipse会把/webapps/文�g夹下的所有内容复制到Web服务器下�Q��ƈ且把webapps改名��Web应用�E�序的Eclipse��目名字�?/div>

�q�样�Q�我们的配置�Q�对于classpath来说也是正确的！Web应用�E�序可以��利地运行�?/div>

三、Ant发布的Web�E�序

可以和上面一栗��把�q�些classpath的源文�g�Q�编译，然后把内部的内容复制到classpath下�?/div>

Web��目�q�行时的classpath是classes和lib。当然也需要把jar包都复制到l(f��)ib下�?/div>

最后，在内容管理\webapps\WEB-INF\jbpm\下放�|�那2个目录。�ƈ把它们设为classpath的源路径�?/div>

目标classpath路径是内容管理\webapps\WEB-INF\classes�?/div>

四、测试jBPM和数据库

建立test源文件夹。提供一个junit��试�c?org.jbpm.test.db.HelloWorldDbTest�?/span>

�q�个�c�M��用字�W�串定义了一个简单的业务�E�序�Q�然后在数据库上完整的执行它�?/div>

执行该单元测试。在应用�E�序的数据库中的2个表�Q?/div>

SELECT * FROM jbpm_processdefinition j;

SELECT * FROM jbpm_processinstance j;

应该有数据�?/div>

��x��Q�jBPM�l��g��成功地加入到Web应用�E�序中了�Q?/div>

附录�Q�HelloWorldDbTest.java源代�?/div>

package org.jbpm.test.db;

import java.util.List;

import junit.framework.TestCase;

import org.jbpm.JbpmConfiguration;
import org.jbpm.JbpmContext;
import org.jbpm.db.GraphSession;
import org.jbpm.graph.def.ProcessDefinition;
import org.jbpm.graph.exe.ProcessInstance;
import org.jbpm.graph.exe.Token;

public class HelloWorldDbTest extends TestCase {

static JbpmConfiguration jbpmConfiguration = null;

static {
    // An example configuration file such as this can be found in
    // 'src/config.files'. Typically the configuration information is in the
    // resource file 'jbpm.cfg.xml', but here we pass in the configuration
    // information as an XML string.

    // First we create a JbpmConfiguration statically. One JbpmConfiguration
    // can be used for all threads in the system, that is why we can safely
    // make it static.
   /**
    *单例对象�?br />    *JbpmConfiguration能够被系�l�中所有线�E�所使用�?br />    *jbpm.cfg.xml�q�个命名方式和Hibernate配置文�g的命名方式一致�?br />    *
    */

    jbpmConfiguration = JbpmConfiguration.parseXmlString(
      "" +

      // A jbpm-context mechanism separates the jbpm core
      // engine from the services that jbpm uses from
      // the environment.
      /*jbpm-context机制在环境中把jbpm核心引擎和jbpm使用的服务分开�?br />       * 持久化服务是jbpm核心引擎使用的一个服务�?br />       *
       * */

      " " +
      "          "             factory='org.jbpm.persistence.db.DbPersistenceServiceFactory' />" +
      " " +

      // Also all the resource files that are used by jbpm are
      // referenced from the jbpm.cfg.xml
      /*
       *string�Q�配�|�了所有jbpm使用的资源文件的路径�?br />       * */

      "       "          value='hibernate.cfg.xml' />" +
      "       "          value='org/jbpm/calendar/jbpm.business.calendar.properties' />" +
      "       "          value='org/jbpm/graph/def/jbpm.default.modules.properties' />" +
      "       "          value='org/jbpm/db/hibernate/jbpm.converter.properties' />" +
      "       "          value='org/jbpm/graph/action/action.types.xml' />" +
      "       "          value='org/jbpm/graph/node/node.types.xml' />" +
      "       "          value='org/jbpm/context/exe/jbpm.varmapping.xml' />" +
      ""
    );
}

public void setUp() {
   //创徏数据库表
    //jbpmConfiguration.createSchema();
}

public void tearDown() {
   //删除数据库表
    //jbpmConfiguration.dropSchema();
}

public void testSimplePersistence() {
    // Between the 3 method calls below, all data is passed via the
    // database. Here, in this unit test, these 3 methods are executed
    // right after each other because we want to test a complete process
    // scenario情节. But in reality, these methods represent different
    // requests to a server.

    // Since we start with a clean, empty in-memory database, we have to
    // deploy the process first. In reality, this is done once by the
    // process developer.
   /**
    * �q�个�Ҏ(gu��)��把业务处理定义通过Hibernate保存到数据库中�?br />    */
    deployProcessDefinition();

    // Suppose we want to start a process instance (=process execution)
    // when a user submits a form in a web application...
    /*假设当一个用��h��交一个表单时�Q�我们要开始一个业务处理的实例/执行�?br />     * �q�可以在Action中执行处理�?br />     */
    processInstanceIsCreatedWhenUserSubmitsWebappForm();

    // Then, later, upon the arrival of an asynchronous message the
    // execution must continue.
    /*
     * 然后�Q�直到异步消息来刎ͼ�才��l�执行业务处理实例的余下的工作流�E��?br />     * */
    theProcessInstanceContinuesWhenAnAsyncMessageIsReceived();
}

public void deployProcessDefinition() {
    // This test shows a process definition and one execution
    // of the process definition. The process definition has
    // 3 nodes: an unnamed start-state, a state 's' and an
    // end-state named 'end'.
   /*
    * �q�个�Ҏ(gu��)��把业务处理定义通过Hibernate保存到数据库中�?br />    *
    * */
    ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
      "" +
      " " +
      "    " +
      " " +
      " " +
      "    " +
      " " +
      " " +
      ""
    );

    // Lookup the pojo persistence context-builder that is configured above
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {
      // Deploy the process definition in the database
      jbpmContext.deployProcessDefinition(processDefinition);

    } finally {
      // Tear down the pojo persistence context.
      // This includes flush the SQL for inserting the process definition
      // to the database.
    /*
    * 关闭jbpm上下文。删除pojo持久化上下文�?br />    * �q�包括刷新SQL来真正的把业务处理定义插入到数据库中�?br />    * */
      jbpmContext.close();
    }
}

public void processInstanceIsCreatedWhenUserSubmitsWebappForm() {
// The code in this method could be inside a struts-action
// or a JSF managed bean.

    // Lookup the pojo persistence context-builder that is configured above
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {
/*
* 图表会话�Q�是图表定义/业务处理定义相关的数据库层面的会话。应该也是一个Hibernate会话�?br /> * 可以从JBpm上下文这个数据库----业务处理定义、实例等得到业务处理定义会话�?br /> *
* */
      GraphSession graphSession = jbpmContext.getGraphSession();
      //从数据库中根据业务处理定义的名字得到一个业务处理定义�?br />      ProcessDefinition processDefinition =
          graphSession.findLatestProcessDefinition("hello world");

      // With the processDefinition that we retrieved from the database, we
      // can create an execution of the process definition just like in the
      // hello world example (which was without persistence).
      /*
       * 创徏业务处理定义的一个实例�?br />       *
       * */
      ProcessInstance processInstance =
          new ProcessInstance(processDefinition);

      Token token = processInstance.getRootToken();
      assertEquals("start", token.getNode().getName());
      // Let's start the process execution
      token.signal();
      // Now the process is in the state 's'.
      assertEquals("s", token.getNode().getName());

      // Now the processInstance is saved in the database. So the
      // current state of the execution of the process is stored in the
      // database.
      /*
       * 执行一步工作流�E�后�Q��用jbpmContext保存�q�个业务处理实例�q�数据库�?br />       *    所以现在就把业务处理实例的执行状态也保存�q�了数据库�?br />       * 因�ؓ�Q�业务处理定义的实例 �q�个�c�M��是一个Model�c�，用于��理一个业务处理定义的执行的所有信息，
       * 是一个多例模式的Model�?br />       *
       * */
      jbpmContext.save(processInstance);
      // The method below will get the process instance back out
      // of the database and resume execution by providing another
      // external signal.

    } finally {
      // Tear down the pojo persistence context.
      jbpmContext.close();
    }
}

public void theProcessInstanceContinuesWhenAnAsyncMessageIsReceived() {
    // The code in this method could be the content of a message driven bean.
    //�q�个�Ҏ(gu��)��可能在消息驱动Bean�q�个�q�程业务代理�c�M��?br />    // Lookup the pojo persistence context-builder that is configured above
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {

      GraphSession graphSession = jbpmContext.getGraphSession();
      // First, we need to get the process instance back out of the database.
      // There are several options to know what process instance we are dealing
      // with here. The easiest in this simple test case is just to look for
      // the full list of process instances. That should give us only one
      // result. So let's look up the process definition.

      ProcessDefinition processDefinition =
          graphSession.findLatestProcessDefinition("hello world");

      // Now, we search for all process instances of this process definition.
      /*
       * �Ҏ(gu��)��业务处理定义的id得到数据库中所有的业务处理实例。这表明�Q�数据库中应该存�?张表
       * 它们�?#160; 一对多的关�p�R�?br />       *
       * */
      List processInstances =
          graphSession.findProcessInstances(processDefinition.getId());

      // Because we know that in the context of this unit test, there is
      // only one execution. In real life, the processInstanceId can be
      // extracted from the content of the message that arrived or from
      // the user making a choice.
      ProcessInstance processInstance =
          (ProcessInstance) processInstances.get(0);

      // Now we can continue the execution. Note that the processInstance
      // delegates signals to the main path of execution (=the root token).
      processInstance.signal();

      // After this signal, we know the process execution should have
      // arrived in the end-state.
      assertTrue(processInstance.hasEnded());

      // Now we can update the state of the execution in the database
      jbpmContext.save(processInstance);

    } finally {
      // Tear down the pojo persistence context.
      jbpmContext.close();
    }
}
}

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向应用程序中加入jBPM�l��g