如何解决无法在Spring Boot中实现Drools KieSession持久性
我试图在Spring Boot Maven项目中使用KieSession的持久性功能来实现Drools。遵循this documentation进行实施。可以在普通的Java应用程序中做到这一点，但是在Spring Boot应用程序中尝试这样做时却出现异常。
下面是实现。
项目结构
配置类
@Configuration
public class PersistentDroolConfig {
public static Long KIE_SESSION_ID;
private final KieServices kieServices = KieServices.Factory.get();
@Bean
public KieSession kieSession() {
KieSession kieSession = kieServices.getStoreServices().newKieSession(getKieBase(),null,getEnv());
PersistentDroolConfig.KIE_SESSION_ID = kieSession.getIdentifier();
return kieSession;
}
public KieServices getKieServices() {
initDataSource();
return kieServices;
}
public KieBase getKieBase() {
KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
kieFileSystem.write(ResourceFactory.newClassPathResource("rules/rules.drl"));
final KieRepository kieRepository = kieServices.getRepository();
kieRepository.addKieModule(kieRepository::getDefaultReleaseId);
KieBuilder kb = kieServices.newKieBuilder(kieFileSystem);
kb.buildAll();
KieModule kieModule = kb.getKieModule();
KieContainer kieContainer = kieServices.newKieContainer(kieModule.getReleaseId());
return kieContainer.getKieBase();
}
public Environment getEnv() {
Environment env = kieServices.newenvironment();
env.set(EnvironmentName.ENTITY_MANAGER_FACTORY,Persistence.createEntityManagerFactory("org.drools.persistence.jpa"));
env.set(EnvironmentName.TRANSACTION_MANAGER,TransactionManagerServices.getTransactionManager());
return env;
}
private void initDataSource() {
PoolingDataSource ds = new PoolingDataSource();
ds.setUniqueName("jdbc/BitronixJTADataSource");
ds.setClassName("com.MysqL.cj.jdbc.MysqLXADataSource");
ds.setMaxPoolSize(3);
ds.setAllowLocalTransactions(true);
ds.getDriverProperties().put("user","root");
ds.getDriverProperties().put("password","1234");
ds.getDriverProperties().put("URL","jdbc:MysqL://localhost:3306/drool_demo");
ds.init();
}
}
控制器类
@RestController
public class OfferController {
@Autowired
private KieSession kieSession;
@GetMapping("/order/{card-type}/{price}")
public Order order(@PathVariable("card-type") String cardType,@PathVariable int price) {
Order order = new Order(cardType,price);
kieSession.insert(order);
kieSession.fireAllRules();
return order;
}
}
情况介绍
public class Order implements Serializable {
private String name;
private String cardType;
private int discount;
private int price;
public Order(String cardType,int price) {
this.cardType = cardType;
this.price = price;
}
// setters and getters
// toString()
}
persistence.xml
<persistence version="2.0"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd
http://java.sun.com/xml/ns/persistence/orm http://java.sun.com/xml/ns/persistence/orm_2_0.xsd"
xmlns:orm="http://java.sun.com/xml/ns/persistence/orm"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="org.drools.persistence.jpa"
transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>jdbc/BitronixJTADataSource</jta-data-source>
<class>org.drools.persistence.info.SessionInfo</class>
<class>org.drools.persistence.info.WorkItemInfo</class>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MysqLDialect" />
<property name="hibernate.max_fetch_depth" value="3" />
<property name="hibernate.hbm2ddl.auto" value="create" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.BTMTransactionManagerLookup" />
</properties>
</persistence-unit>
</persistence>
pom.xml 文件中包含的依赖项如下：
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>MysqL</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.github.marcus-nl.btm</groupId>
<artifactId>btm</artifactId>
<version>3.0.0-mk1</version>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-decisiontables</artifactId>
<version>${drools-version}</version>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-core</artifactId>
<version>${drools-version}</version>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-compiler</artifactId>
<version>${drools-version}</version>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-persistence-jpa</artifactId>
<version>${drools-version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
错误堆栈跟踪：
Caused by: org.hibernate.engine.jndi.JndiException: Unable to lookup JNDI name [jdbc/BitronixJTADataSource]
Caused by: javax.naming.NameNotFoundException: unable to find a bound object at name 'jdbc/BitronixJTADataSource'
该项目也可以在this repository中找到。
更新1：
实现@jccampanero的答案后，我有了更新的堆栈跟踪：
Caused by: org.hibernate.HibernateException: Unable to perform isolated work
Caused by: java.sql.sqlSyntaxErrorException: Table 'drool_demo.sessioninfo_id_seq' doesn't exist
更新2：
进一步研究之后，我发现Drools由于语法错误而没有制作必要的表。由于Stackoverflow具有文本限制，因此仅在此处发布了重要的异常消息。就是这样：
Hibernate: drop table if exists SessionInfo
Hibernate: drop table if exists WorkItemInfo
Hibernate: create table SessionInfo (id bigint not null auto_increment,lastModificationDate datetime,rulesByteArray longblob,startDate datetime,OPTLOCK integer,primary key (id)) type=MyISAM
2020-10-09 23:49:59.554 WARN 11376 --- [ main] o.h.t.s.i.ExceptionHandlerLoggedImpl : GenerationTarget encountered exception accepting command : Error executing DDL "create table SessionInfo (id bigint not null auto_increment,primary key (id)) type=MyISAM" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table SessionInfo (id bigint not null auto_increment,primary key (id)) type=MyISAM" via JDBC Statement
Caused by: java.sql.sqlSyntaxErrorException: You have an error in your sql Syntax; check the manual that corresponds to your MysqL server version for the right Syntax to use near 'type=MyISAM' at line 1
Hibernate: create table WorkItemInfo (workItemId bigint not null auto_increment,creationDate datetime,name varchar(255),processInstanceId bigint not null,state bigint not null,workItemByteArray longblob,primary key (workItemId)) type=MyISAM
2020-10-09 23:49:59.556 WARN 11376 --- [ main] o.h.t.s.i.ExceptionHandlerLoggedImpl : GenerationTarget encountered exception accepting command : Error executing DDL "create table WorkItemInfo (workItemId bigint not null auto_increment,primary key (workItemId)) type=MyISAM" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table WorkItemInfo (workItemId bigint not null auto_increment,primary key (workItemId)) type=MyISAM" via JDBC Statement
Caused by: java.sql.sqlSyntaxErrorException: You have an error in your sql Syntax; check the manual that corresponds to your MysqL server version for the right Syntax to use near 'type=MyISAM' at line 1
解决方法
您是否在容器中配置了jndi数据源？
<Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"
maxTotal="100" maxIdle="30" maxWaitMillis="10000"
username="javauser" password="javadude" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/javatest"/>
Tomcat jndi data source example
,我认为您的配置有问题。 getKieServices类的PersistentDroolConfig方法永远不会被调用，因此，initDataSource方法也不会初始化您的数据源。
也许您可以尝试修改PersistentDroolConfig，如下所示：
@Configuration
public class PersistentDroolConfig {
public static Long KIE_SESSION_ID;
private KieServices kieServices;
@PostContruct
private void init() {
this.initDataSource();
this.kieServices = KieServices.Factory.get();
}
@Bean
public KieSession kieSession() {
KieSession kieSession;
if (KIE_SESSION_ID == null) {
kieSession = createNewKieSession();
KIE_SESSION_ID = kieSession.getIdentifier();
return kieSession;
} else {
kieSession = getPersistentKieSession();
KIE_SESSION_ID = kieSession.getIdentifier();
return kieSession;
}
}
public KieBase getKieBase() {
KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
kieFileSystem.write(ResourceFactory.newClassPathResource("rules/rules.drl"));
final KieRepository kieRepository = kieServices.getRepository();
kieRepository.addKieModule(new KieModule() {
@Override
public ReleaseId getReleaseId() {
return kieRepository.getDefaultReleaseId();
}
});
KieBuilder kb = kieServices.newKieBuilder(kieFileSystem);
kb.buildAll();
KieModule kieModule = kb.getKieModule();
KieContainer kieContainer = kieServices.newKieContainer(kieModule.getReleaseId());
KieBase kieBase = kieContainer.getKieBase();
return kieBase;
}
public Environment getEnv() {
Environment env = kieServices.newEnvironment();
env.set(EnvironmentName.ENTITY_MANAGER_FACTORY,Persistence.createEntityManagerFactory("org.drools.persistence.jpa"));
env.set(EnvironmentName.TRANSACTION_MANAGER,TransactionManagerServices.getTransactionManager());
return env;
}
private KieSession createNewKieSession() {
KieSession kieSession = kieServices.getStoreServices().newKieSession(getKieBase(),null,getEnv());
PersistentDroolConfig.KIE_SESSION_ID = kieSession.getIdentifier();
return kieSession;
}
private KieSession getPersistentKieSession() {
return kieServices.getStoreServices().loadKieSession(KIE_SESSION_ID,getKieBase(),getEnv());
}
private void initDataSource() {
PoolingDataSource ds = new PoolingDataSource();
ds.setUniqueName("jdbc/BitronixJTADataSource");
ds.setClassName("com.mysql.cj.jdbc.MysqlXADataSource");
ds.setMaxPoolSize(3);
ds.setAllowLocalTransactions(true);
ds.getDriverProperties().put("user","root");
ds.getDriverProperties().put("password","1234");
ds.getDriverProperties().put("URL","jdbc:mysql://localhost:3306/drool_demo");
ds.init();
}
}
更新
如不同评论中所述，进行了这些更改之后，出现了与SESSIONINFO_ID_SEQ序列有关的问题，该序列用于生成实体SessionInfo的字段id的值。 / p>
问题似乎与使用的Hibernate和MySQL版本有关。
要解决该问题，必须对persistence.xml文件进行几处更改。
首先，应包含以下属性：
<property name="hibernate.id.new_generator_mappings" value="false" />
在Drools示例和test cases中经常使用它。有关详细说明，请参见this Vlad Mihalcea的出色文章。
此配置属性的包含产生了一个与所使用的MySQL方言有关的新问题。它应该更改为：
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
使用此配置，应用程序应该可以平稳运行。
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