Java Spring Batch 使用嵌入式数据库存储元数据，使用第二个数据库存储其他数据

Question

我在使用 Spring Batch 时遇到了一些麻烦。我处于这种情况:我必须分析文件中的数据并将所有内容插入数据库(Oracle)。我面临的问题是，当我尝试配置用于保存数据的数据库时，应用程序崩溃并关闭。我收到此错误消息:

 :: Spring Boot ::        (v2.0.0.RELEASE)

2018-03-28 17:21:25.033  INFO 9912 --- [           main] c.e.demo.SpringMultiprocessApplication   : Starting SpringMultiprocessApplication on XXXel with PID 9912 (C:\Users\......\target\classes started by XXXEl in C:\Users\......)
2018-03-28 17:21:25.037  INFO 9912 --- [           main] c.e.demo.SpringMultiprocessApplication   : No active profile set, falling back to default profiles: default
2018-03-28 17:21:25.094  INFO 9912 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5af97850: startup date [Wed Mar 28 17:21:25 CEST 2018]; root of context hierarchy
2018-03-28 17:21:25.491  INFO 9912 --- [           main] o.s.b.f.xml.XmlBeanDefinitionReader      : Loading XML bean definitions from class path resource [batchjob.xml]
2018-03-28 17:21:25.879  WARN 9912 --- [           main] o.s.c.a.ConfigurationClassEnhancer       : @Bean method ScopeConfiguration.stepScope is non-static and returns an object assignable to Spring's BeanFactoryPostProcessor interface. This will result in a failure to process annotations such as @Autowired, @Resource and @PostConstruct within the method's declaring @Configuration class. Add the 'static' modifier to this method to avoid these container lifecycle issues; see @Bean javadoc for complete details.
2018-03-28 17:21:25.889  WARN 9912 --- [           main] o.s.c.a.ConfigurationClassEnhancer       : @Bean method ScopeConfiguration.jobScope is non-static and returns an object assignable to Spring's BeanFactoryPostProcessor interface. This will result in a failure to process annotations such as @Autowired, @Resource and @PostConstruct within the method's declaring @Configuration class. Add the 'static' modifier to this method to avoid these container lifecycle issues; see @Bean javadoc for complete details.
2018-03-28 17:21:25.897  INFO 9912 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Replacing scope 'step' from [org.springframework.batch.core.scope.StepScope@388ba540] to [org.springframework.batch.core.scope.StepScope@47605f2f]
2018-03-28 17:21:25.899  INFO 9912 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'itemReader' with a different definition: replacing [Generic bean: class [com.example.demo.step.Reader]; scope=step; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=false; primary=false; factoryBeanName=null; factoryMethodName=reader; initMethodName=null; destroyMethodName=null; defined in class path resource [batchjob.xml]] with [Root bean: class [org.springframework.aop.scope.ScopedProxyFactoryBean]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in BeanDefinition defined in class path resource [batchjob.xml]]
2018-03-28 17:21:25.899  INFO 9912 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'itemProcessor' with a different definition: replacing [Generic bean: class [com.example.demo.step.Processor]; scope=step; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=false; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in class path resource [batchjob.xml]] with [Root bean: class [org.springframework.aop.scope.ScopedProxyFactoryBean]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in BeanDefinition defined in class path resource [batchjob.xml]]
2018-03-28 17:21:25.899  INFO 9912 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'itemWriter' with a different definition: replacing [Generic bean: class [com.example.demo.step.Writer]; scope=step; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=false; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in class path resource [batchjob.xml]] with [Root bean: class [org.springframework.aop.scope.ScopedProxyFactoryBean]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in BeanDefinition defined in class path resource [batchjob.xml]]
2018-03-28 17:21:26.210  INFO 9912 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2018-03-28 17:21:26.225  INFO 9912 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-03-28 17:21:26.225  INFO 9912 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.28
2018-03-28 17:21:26.229  INFO 9912 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files\Java\jre1.8.0_161\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:/Program Files/Java/jre1.8.0_161/bin/server;C:/Program Files/Java/jre1.8.0_161/bin;C:/Program Files/Java/jre1.8.0_161/lib/amd64;C:\ProgramData\Oracle\Java\javapath;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\AMD\ATI.ACE\Core-Static;C:\Program Files\PuTTY\;C:\Program Files\Git\cmd;C:\Users\XXXel\AppData\Local\Microsoft\WindowsApps;C:\Program Files (x86)\maven3.2.5\apache-maven-3.2.5\bin;;C:\Program Files (x86)\eclipse\eclipse;;.]
2018-03-28 17:21:26.285  INFO 9912 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-03-28 17:21:26.286  INFO 9912 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1196 ms
2018-03-28 17:21:26.397  INFO 9912 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/]
2018-03-28 17:21:26.417  INFO 9912 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-03-28 17:21:26.417  INFO 9912 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-03-28 17:21:26.417  INFO 9912 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-03-28 17:21:26.417  INFO 9912 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-03-28 17:21:26.478  INFO 9912 --- [           main] o.s.j.d.DriverManagerDataSource          : Loaded JDBC driver: oracle.jdbc.OracleDriver
2018-03-28 17:21:26.942  INFO 9912 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5af97850: startup date [Wed Mar 28 17:21:25 CEST 2018]; root of context hierarchy
2018-03-28 17:21:27.005  INFO 9912 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/runjob]}" onto public java.lang.String com.example.demo.controller.WebController.handle() throws java.lang.Exception
2018-03-28 17:21:27.009  INFO 9912 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-03-28 17:21:27.010  INFO 9912 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-03-28 17:21:27.038  INFO 9912 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-28 17:21:27.038  INFO 9912 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-28 17:21:27.069  INFO 9912 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-28 17:21:27.396  INFO 9912 --- [           main] o.s.b.c.r.s.JobRepositoryFactoryBean     : No database type set, using meta data indicating: ORACLE
2018-03-28 17:21:27.409  INFO 9912 --- [           main] o.s.b.c.l.support.SimpleJobLauncher      : No TaskExecutor has been set, defaulting to synchronous executor.
2018-03-28 17:21:27.595  INFO 9912 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-03-28 17:21:27.633  INFO 9912 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-03-28 17:21:27.635  INFO 9912 --- [           main] c.e.demo.SpringMultiprocessApplication   : Started SpringMultiprocessApplication in 2.845 seconds (JVM running for 3.316)
2018-03-28 17:21:27.638  INFO 9912 --- [           main] o.s.b.a.b.JobLauncherCommandLineRunner   : Running default command line with: []
2018-03-28 17:21:27.745  INFO 9912 --- [           main] o.s.b.f.xml.XmlBeanDefinitionReader      : Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml]
2018-03-28 17:21:27.771  INFO 9912 --- [           main] o.s.jdbc.support.SQLErrorCodesFactory    : SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase, Hana]
2018-03-28 17:21:27.809  INFO 9912 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-03-28 17:21:27.816 ERROR 9912 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:793) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:774) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:335) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at com.example.demo.SpringMultiprocessApplication.main(SpringMultiprocessApplication.java:18) [classes/:na]
Caused by: org.springframework.jdbc.BadSqlGrammarException: PreparedStatementCallback; bad SQL grammar [SELECT JOB_INSTANCE_ID, JOB_NAME from BATCH_JOB_INSTANCE where JOB_NAME = ? order by JOB_INSTANCE_ID desc]; nested exception is java.sql.SQLSyntaxErrorException: ORA-00942: table or view does not exist

    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:235) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1402) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:620) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:657) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:688) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:700) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.batch.core.repository.dao.JdbcJobInstanceDao.getJobInstances(JdbcJobInstanceDao.java:230) ~[spring-batch-core-4.0.0.RELEASE.jar:4.0.0.RELEASE]
    at org.springframework.batch.core.explore.support.SimpleJobExplorer.getJobInstances(SimpleJobExplorer.java:173) ~[spring-batch-core-4.0.0.RELEASE.jar:4.0.0.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:338) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:197) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) ~[spring-batch-core-4.0.0.RELEASE.jar:4.0.0.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at com.sun.proxy.$Proxy80.getJobInstances(Unknown Source) ~[na:na]
    at org.springframework.batch.core.JobParametersBuilder.getNextJobParameters(JobParametersBuilder.java:254) ~[spring-batch-core-4.0.0.RELEASE.jar:4.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:162) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:179) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:134) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:128) ~[spring-boot-autoconfigure-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:790) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
    ... 5 common frames omitted
Caused by: java.sql.SQLSyntaxErrorException: ORA-00942: table or view does not exist

    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:445) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:879) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:450) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:192) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:207) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:884) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1167) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1289) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3584) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3628) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:1493) ~[ojdbc6-11.2.0.3.jar:11.2.0.3.0]
    at org.springframework.jdbc.core.JdbcTemplate$1.doInPreparedStatement(JdbcTemplate.java:666) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:605) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    ... 27 common frames omitted

2018-03-28 17:21:27.817  INFO 9912 --- [           main] ConfigServletWebServerApplicationContext : Closing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5af97850: startup date [Wed Mar 28 17:21:25 CEST 2018]; root of context hierarchy
2018-03-28 17:21:27.818  INFO 9912 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown

我是 Spring 的新手，但据我所知，Spring Batch 正在尝试访问我的数据库并查询它的元数据(SpringBatch 的东西)。现在的问题是:如何告诉 Spring Batch 使用其嵌入式数据库来保存其数据(元数据)而不是尝试访问我的数据库？

application.properties

spring.batch.job.enabled=true
spring.batch.initialize-schema=EMBEDDED

spring.datasource.url=jdbc:oracle:thin:@localhost:1521:ASDF
spring.datasource.username=USERNAME
spring.datasource.password=PASSWORD
spring.datasource.driver-class-name=oracle.jdbc.OracleDriver

MultipleDBConfig.java 用于配置数据库的Bean

@Configuration
public class MultipleDBConfig {

    @Autowired
    private Environment env;

    @Bean
    public DataSource customDataSource() {

        DriverManagerDataSource dataSource = new DriverManagerDataSource();

        dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));
        dataSource.setPassword(env.getProperty("spring.datasource.password"));

        return dataSource;
    }
}

Answer 1

我以前就是这样解决的。这是非启动和旧的 Spring，但它可能仍然适用于您所处的任何环境。默认情况下，setDataSource() 将与您的 Oracle ds 一起注入(inject)，但如果您阻止它被注入(inject)注入(inject)后，Spring Batch 只会将这些细节存储在内存中。

如果您想要使用不同的数据源(即，如果您希望批处理元数据仍然保留)，您可以使用 @Qualifier 指定不同的数据源 bean 并调用 super.setDataSource(dataSource);.可能还有其他方法可以做到这一点，几年没碰过这段代码了。

@Configuration
@EnableBatchProcessing
public class BatchConfig extends DefaultBatchConfigurer {

    @Override
    @Autowired
    public void setDataSource(DataSource dataSource) {
        // If we don't provide a datasource, an in-memory map will be used.
    }
}