activiti 如何使用database前缀来区分activiti数据库和业务数据库

为什么80%的码农都做不了架构师？>>>

第一步是先集成好activiti，我使用的是5.22.0，使用springboot集成，pom文件如下：

​
<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.RELEASE</version>
	</parent>
<span class="hljs-tag">&lt;<span class="hljs-name">properties</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">java.version</span>&gt;</span>1.8<span class="hljs-tag">&lt;/<span class="hljs-name">java.version</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">activiti.version</span>&gt;</span>5.22.0<span class="hljs-tag">&lt;/<span class="hljs-name">activiti.version</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">properties</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">dependencies</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-starter-thymeleaf<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
	<span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-starter-web<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
	<span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.activiti<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>activiti-spring-boot-starter-basic<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">version</span>&gt;</span>${activiti.version}<span class="hljs-tag">&lt;/<span class="hljs-name">version</span>&gt;</span>
	<span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>mysql<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>mysql-connector-java<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">scope</span>&gt;</span>runtime<span class="hljs-tag">&lt;/<span class="hljs-name">scope</span>&gt;</span>
	<span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
	<span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-starter-test<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
		<span class="hljs-tag">&lt;<span class="hljs-name">scope</span>&gt;</span>test<span class="hljs-tag">&lt;/<span class="hljs-name">scope</span>&gt;</span>
	<span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">dependencies</span>&gt;</span>

​

配置springboot的启动配置文件中的数据库，我们指定一个独立的数据库来进行创建activiti的数据库

spring: 
  datasource: 
    url: jdbc:mysql://localhost:3306/activiti?characterEncoding=utf8
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    show-sql: true
    hibernate:
      ddl-auto: false
debug: true

运行启动类，

@SpringBootApplication
public class ActivitiApplication {
<span class="hljs-comment">/**
 * Description: 
 * <span class="hljs-doctag">@author</span> Liu Wenjie
 * <span class="hljs-doctag">@date</span> 2018年2月11日 上午10:38:00
 * <span class="hljs-doctag">@param</span> args
 */</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">main</span><span class="hljs-params">(String[] args)</span> </span>{
	SpringApplication.run(ActivitiApplication.class, args);
}

}

我们打开数据库，可以看到已经动态生成了对应的数据库文件，而正常业务我们不想使用activiti的数据库作为数据源的链接源，那么我们就修改配置文件的链接到test 数据库上，修改后的配置如下：

spring: 
  datasource: 
    url: jdbc:mysql://localhost:3306/test?characterEncoding=utf8
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    show-sql: true
    hibernate:
      ddl-auto: false
debug: true

如果我们现在启动，那么activiti会默认在test database上创建数据库表结构，这时候我们需要增加一个配置类，

@Component
public class ActivitiProcessEngineConfigurationConfigurer implements ProcessEngineConfigurationConfigurer {
<span class="hljs-comment">/**
 * &lt;p&gt;Description: &lt;/p&gt;
 * <span class="hljs-doctag">@author</span> Liu Wenjie
 * <span class="hljs-doctag">@date</span> 2018年2月12日 上午11:09:19
 * <span class="hljs-doctag">@param</span> processEngineConfiguration
 * <span class="hljs-doctag">@see</span> org.activiti.spring.boot.ProcessEngineConfigurationConfigurer#configure(org.activiti.spring.SpringProcessEngineConfiguration)
 */</span>
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">configure</span><span class="hljs-params">(SpringProcessEngineConfiguration processEngineConfiguration)</span> </span>{
	processEngineConfiguration.setDatabaseTablePrefix(<span class="hljs-string">"activiti."</span>);
	processEngineConfiguration.setTablePrefixIsSchema(<span class="hljs-keyword">true</span>);
	processEngineConfiguration.setDatabaseSchemaUpdate(<span class="hljs-string">"no"</span>);
}

}

configure方法里的方法是为了让activiti开始时不创建也不校验activiti版本，然后在业务执行的时候都增加对应的数据库前缀，这样变相的解决了activiti的表与业务表不在同一个数据库的问题。

activiti的源码关键点在：

DbSqlSession.class中的以下方法：

public void performSchemaOperationsProcessEngineBuild() {
    String databaseSchemaUpdate = Context.getProcessEngineConfiguration().getDatabaseSchemaUpdate();
    if (ProcessEngineConfigurationImpl.DB_SCHEMA_UPDATE_DROP_CREATE.equals(databaseSchemaUpdate)) {
      try {
        dbSchemaDrop();
      } catch (RuntimeException e) {
        // ignore
      }
    }
    if ( org.activiti.engine.ProcessEngineConfiguration.DB_SCHEMA_UPDATE_CREATE_DROP.equals(databaseSchemaUpdate) 
         || ProcessEngineConfigurationImpl.DB_SCHEMA_UPDATE_DROP_CREATE.equals(databaseSchemaUpdate)
         || ProcessEngineConfigurationImpl.DB_SCHEMA_UPDATE_CREATE.equals(databaseSchemaUpdate)
       ) {
      dbSchemaCreate();
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (org.activiti.engine.ProcessEngineConfiguration.DB_SCHEMA_UPDATE_FALSE.equals(databaseSchemaUpdate)) {
  dbSchemaCheckVersion();
  
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (ProcessEngineConfiguration.DB_SCHEMA_UPDATE_TRUE.equals(databaseSchemaUpdate)) {
  dbSchemaUpdate();
}

}

                                    </div>原文地址：https://my.oschina.net/6WiVT5YRI7U/blog/1621605
                                        </div>

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