Every time there is a new Http request, I need to change the database currently used and whose name is part of the Http URL request. I'm trying to use the following code, but when I call the service and it's executing, I can't call it again until the previous service completes or it crashes. I noticed the problem was "No database selected" but I don't know how to change the database without crashing :( If you don't have one already, you have to create the database and tables automatically through code, so I use Flyway.
I need to use the name passed from the user via the requested url The URL pattern is: .../api/v1/{db_name}/... I'm using jdbcTemplate, but JPA solutions are welcome :)
try {
DriverManagerDataSource dataSource = (DriverManagerDataSource) jdbcTemplate.getDataSource();
String urlBase = env.getProperty("spring.datasource.url");
dataSource.setUrl(urlBase);
dataSource.setSchema(name);
Flyway flyway = Flyway.configure()
.dataSource(dataSource)
.defaultSchema(name)
.load();
flyway.migrate();
dataSource.setUrl(urlBase+name);
return true;
}catch (Exception e){
e.printStackTrace();
}`
Exception when I call link twice from two different clients:
StatementCallback; uncategorized SQLException for SQL [INSERT INTO statistiche_plu_giornaliere (id, id_dbLocale, idDevice, id_plu, descrizione, importo_totale, qta_totale_plu, qta_reso_storno, qta_reale, data, importo_sconti, importo_maggiorazioni, importo_reale, resi, id_reparto, tipo_riga) VALUES (0,256,'0AB1115556633569',0,'1LT PROSECCO',24.000000,2.000000,0.000000,2.000000,'',0.000000,0.000000,24.000000,0.000000,0,0)]; SQL state [3D000]; error code [1046]; No database selected; nested exception is java.sql.SQLException: No database selected
at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1542)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:393)
at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:558)
at com.trei.statistiche_cloud.db.DbHandler.updateStatisticheGiornaliere(DbHandler.java:119)
at com.trei.statistiche_cloud.http.RestController.aggiornaDb(RestController.java:49)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:696)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:779)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:186)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:142)
at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:82)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:891)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1784)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.sql.SQLException: No database selected
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1334)
at com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2084)
at com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1245)
at org.springframework.jdbc.core.JdbcTemplateUpdateStatementCallback.doInStatement(JdbcTemplate.java:546)
at org.springframework.jdbc.core.JdbcTemplateUpdateStatementCallback.doInStatement(JdbcTemplate.java:543)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:381)` 
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I think your use case is very dangerous because you are basically providing the secret of the database via an HTTP/s call, other inconveniences include:
Loading the database for every request will significantly increase the response time of the application
Leads to scalability and resource consumption issues.
Instead, it is generally recommended to set up a Spring Boot application to initiate a database connection immediately upon startup and keep it open for the remainder of the program's lifecycle. This strategy allows for greater scalability and faster database access.
If you need to configure multiple databases for the same application, you can manually define multiple data sources. On a per-request basis, you can select which database to query