Activiti指南（建立流程引擎）

建立流程引擎

正如以前在maven依賴關係摘要中所建議的，Activiti利用Simple Logging Facade for Java（slf4j）進行日誌記錄，在此示例應用程序中，咱們將使用log4j日誌記錄實現，將log4j.properties文件添加到項目中。

文件：$mvnProject/src/main/resources/log4j.properties

log4j.rootLogger=DEBUG, ACT

log4j.appender.ACT=org.apache.log4j.ConsoleAppender
log4j.appender.ACT.layout=org.apache.log4j.PatternLayout
log4j.appender.ACT.layout.ConversionPattern= %d{hh:mm:ss,SSS} [%t] %-5p %c %x - %m%n

建立一個新類，包含空的main方法。

文件：$mvnProject/src/main/java/com/example/OnboardingRequest.java

package com.example;

public class OnboardingRequest {
  public static void main(String[] args) {
    
  }
}

添加到main入口點的是建立流程引擎，添加到OnboardingRequest.java，以下圖所示：

package com.example;

import org.activiti.engine.ProcessEngine;
import org.activiti.engine.ProcessEngineConfiguration;
import org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration;

public class OnboardingRequest {
  public static void main(String[] args) {
    ProcessEngineConfiguration cfg = new StandaloneProcessEngineConfiguration()
      .setJdbcUrl("jdbc:h2:mem:activiti;DB_CLOSE_DELAY=1000")
      .setJdbcUsername("sa")
      .setJdbcPassword("")
      .setJdbcDriver("org.h2.Driver")
      .setDatabaseSchemaUpdate(ProcessEngineConfiguration.DB_SCHEMA_UPDATE_TRUE);
    ProcessEngine processEngine = cfg.buildProcessEngine();
    String pName = processEngine.getName();
    String ver = ProcessEngine.VERSION;
    System.out.println("ProcessEngine [" + pName + "] Version: [" + ver + "]");
  }
}

• 導入Activiti流程引擎和配置。
• 導入獨立環境的配置助手（例如，不使用依賴關係管理器）
• 使用基於內存的h2嵌入式數據庫建立流程引擎。
• 顯示流程引擎配置和Activiti版本。

Activiti支持依賴注入：

• Activiti專爲而且能夠輕鬆利用依賴注入而構建，有關詳細信息，請查看Activiti用戶指南。

Activiti發佈了許多數據庫提供商：

• 「$actUnzipedPack/database/create」中的數據庫腳本
• Activiti用戶指南（各類開發和管理部分）

支持IDE和平臺無關的配置，併爲此快速入門提供簡單性，將一個「fat jar」配置添加到pom.xml中，以下面的所示。

文件：$mvnProject/pom.xml

<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">
...
  <build>
...
    <plugins>
...
      <!-- Maven Assembly Plugin -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>2.4.1</version>
        <configuration>
          <!-- get all project dependencies -->
          <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
          </descriptorRefs>
          <!-- MainClass in mainfest make a executable jar -->
          <archive>
            <manifest>
              <mainClass>com.example.OnboardingRequest</mainClass>
            </manifest>
          </archive>
        </configuration>
        <executions>
          <execution>
            <id>make-assembly</id>
            <!-- bind to the packaging phase -->
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
...
    </plugins>
...
  </build>
...
</project>

經過運行「mvn package」打包代碼。

命令：mvn package

基礎路徑：$mvnProject

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building $quickStartJavaProjectName 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ $quickStartJavaProjectName ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.5.1:compile (default-compile) @ HelloProcess2 ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ HelloProcess2 ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.5.1:testCompile (default-testCompile) @ HelloProcess2 ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ HelloProcess2 ---
[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ HelloProcess2 ---
[INFO] Building jar: $mvnProject/target/$quickStartJavaProjectName-0.0.1-SNAPSHOT.jar
[INFO] META-INF/maven/$quickStartJavaProjectName/HelloProcess2/pom.xml already added, skipping
[INFO] META-INF/maven/$quickStartJavaProjectName/$quickStartJavaProjectName/pom.properties already added, skipping
[INFO] 
[INFO] --- maven-assembly-plugin:2.4.1:single (make-assembly) @ $quickStartJavaProjectName ---
[INFO] Building jar: $mvnProject/target/$quickStartJavaProjectName-0.0.1-SNAPSHOT-jar-with-dependencies.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.029s
[INFO] Finished at: Sun Nov 27 07:23:43 EST 2016
[INFO] Final Memory: 33M/702M
[INFO] ------------------------------------------------------------------------

• 你的輸出可能看起來不一樣，這裏的重要輸出是「BUILD SUCCESS」之上的行，顯示了jar依賴的成功：
• 「[INFO] Building jar: $mvnProject/target/$quickStartJavaProjectName-0.0.1-SNAPSHOT-jar-with-dependencies.jar」

支持IDE和平臺獨立以及本快速入門的簡單性，從命令行運行Java程序，以下所示。

命令：java -jar target/ActivitiDeveloperQuickStart-0.0.1-SNAPSHOT-jar-with-dependencies.jar

或

java -jar target/$quickStartJavaProjectName-0.0.1-SNAPSHOT-jar-with-dependencies.jar

11:45:32,849 [main] DEBUG org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl  - initializing datasource to db: jdbc:h2:mem:activiti;DB_CLOSE_DELAY=1000
11:45:32,856 [main] DEBUG org.apache.ibatis.logging.LogFactory  - Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter.

...

11:45:33,777 [main] DEBUG org.activiti.engine.impl.db.DbSqlSession  - SQL: create table ACT_PROCDEF_INFO ( 
ID_ varchar(64) not null, 
PROC_DEF_ID_ varchar(64) not null, 
REV_ integer, 
INFO_JSON_ID_ varchar(64), 
primary key (ID_) 
)

...

11:45:33,835 [main] DEBUG org.activiti.engine.impl.db.DbSqlSession  - activiti db schema create for component identity successful
11:45:33,835 [main] DEBUG org.activiti.engine.impl.db.DbSqlSession  - flush summary: 0 insert, 0 update, 0 delete.
11:45:33,835 [main] DEBUG org.activiti.engine.impl.db.DbSqlSession  - now executing flush...
11:45:33,835 [main] DEBUG org.activiti.engine.impl.cfg.standalone.StandaloneMybatisTransactionContext  - firing event committing...
11:45:33,835 [main] DEBUG org.activiti.engine.impl.cfg.standalone.StandaloneMybatisTransactionContext  - committing the ibatis sql session...
11:45:33,835 [main] DEBUG org.activiti.engine.impl.cfg.standalone.StandaloneMybatisTransactionContext  - firing event committed...
11:45:33,836 [main] DEBUG org.apache.ibatis.transaction.jdbc.JdbcTransaction  - Resetting autocommit to true on JDBC Connection [conn0: url=jdbc:h2:mem:activiti user=SA]
11:45:33,836 [main] DEBUG org.apache.ibatis.transaction.jdbc.JdbcTransaction  - Closing JDBC Connection [conn0: url=jdbc:h2:mem:activiti user=SA]
11:45:33,836 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource  - Returned connection 667346055 to pool.
11:45:33,836 [main] DEBUG org.activiti.engine.impl.interceptor.LogInterceptor  - --- SchemaOperationsProcessEngineBuild finished --------------------------------------------------------
11:45:33,836 [main] DEBUG org.activiti.engine.impl.interceptor.LogInterceptor  - 

11:45:33,836 [main] INFO  org.activiti.engine.impl.ProcessEngineImpl  - ProcessEngine default created
ProcessEngine [default] Version: [$actVer]

感興趣的關鍵輸出是打印你的Activiti版本：$actVer它應該與配置在「[INFO] Building jar: $mvnProject/target/$quickStartJavaProjectName-0.0.1-SNAPSHOT-jar-with-dependencies.jar」的版本匹配。

或者，固然，你能夠在IDE中運行相同的程序，例如，從Eclipse中選擇OnboardingRequest.java文件，而後右鍵單擊「Run As> Java Application」。若是從IDE中運行程序，結果應該相同（一般顯示在IDE的控制檯視圖中）。

你已經在這個簡單的Java程序中成功嵌入了Activiti的BPM引擎。

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