AbstractRoutingDataSource strange behaviour

Question

I am newbie in Spring. I use AbstractRoutingDataSource to change db connection in runtime and SpringBoot My code is similar to this https://spring.io/blog/2007/01/23/dynamic-datasource-routing but beans are configured programatically.

public class DatabaseContext {

    private static final ThreadLocal<String> contextHolder = new   ThreadLocal<String>();

    public static void setDatabaseType(String string) {
        contextHolder.set(string);
    }

    public static String getDatabaseType() {
        return (String) contextHolder.get();
    }

    public static void clearDatabaseType() {
        contextHolder.remove();
    }
}

Everything works fine when I change context like that (pseudocode):

public class Application {
    @Autowired
    private MyCrudRepository repository;
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
    @Override run(){
         DatabaseContext.changeContext("db1");
         repository.findAll();          //data from db1 like expected
         DatabaseContext.changeContext("db2");
         repository.findAll();          //data from db2 like expected
    }
}

but when I change context in servlet class (pseudocode)

@Controller
public class MyWebController{
    @RequestMapping(someMapping)
    HttpEntity someMethod(){
         DatabaseContext.changeContext("db1");
         repository.findAll();          //data from db1 like expected
         DatabaseContext.changeContext("db2");
         repository.findAll();          //data from db1
    }

}

Context change just one time and I have no idea what's wrong.