This is a follow up to the question Making spring-data-mongodb multi-tenant
Oliver Gierke explained options how to set-up multi-tenancy for a SpringDataMongo application. I followed his "collection approach" and was quite successful. So far. Problems arise, when I want to customise the MongoTemplate used. Have a look on this example:
#SpringBootApplication
public class MultiTenantMongoApplication {
public static void main(String[] args) {
SpringApplication.run(MultiTenantMongoApplication.class, args);
}
#Bean
public MongoTemplate mongoTemplate(Mongo mongo, #Value("${random.name}") String randomName) throws Exception {
String dbname = "db_" + randomName;
MongoTemplate mongoTemplate = new MongoTemplate(mongo, dbname) {
#SuppressWarnings("unused")
public void shutdown() {
mongo.dropDatabase(dbname);
}
};
return mongoTemplate;
}
}
#Document(collection="#{tenantProvider.getTenantCollectionName('Metric')}")
public class Metric {
}
#Repository
public interface MetricRepository extends MongoRepository<Metric, ObjectId>{}
#Component
public class TenantProvider {
public String getTenantCollectionName(String collectionName) {
...
}
}
This yields the following error:
SpelEvaluationException: EL1007E: Property or field 'tenantProvider'
cannot be found on null
When I remove the definition of the MongoTemplate bean in the application class everything is fine and runs as desired.
Obviously the property provider gets not configured appropriately, when the MongoTemplate is customised. Why is this happening? And what can I do, to get the property in place?
I think the above error is because of the SpEL expression. You can try this way to access the TenantProvider class using the below SpEL expression.
#{T(TenantProvider).getTenantCollectionName('Metric')}
or you can add a fully qualified class name for TenantProvider in the above expression.
Related
I am trying to autowire a component into a custom JsonDeserializer but cannot get it right even with the following suggestions I found:
Autowiring in JsonDeserializer: SpringBeanAutowiringSupport vs HandlerInstantiator
Right way to write JSON deserializer in Spring or extend it
How to customise the Jackson JSON mapper implicitly used by Spring Boot?
Spring Boot Autowiring of JsonDeserializer in Integration test
My final goal is to accept URLs to resources in different microservices and store only the ID of the resource locally. But I don't want to just extract the ID from the URL but also verify that the rest of the URL is correct.
I have tried many things and lost track a bit of what I tried but I believe I tried everything mentioned in the links above. I created tons of beans for SpringHandlerInstantiator, Jackson2ObjectMapperBuilder, MappingJackson2HttpMessageConverter, RestTemplate and others and also tried with setting the SpringHandlerInstantiator in RepositoryRestConfigurer#configureJacksonObjectMapper.
I am using Spring Boot 2.1.6.RELEASE which makes me think something might have changed since some of the linked threads are quite old.
Here's my last attempt:
#Configuration
public class JacksonConfig {
#Bean
public HandlerInstantiator handlerInstantiator(ApplicationContext applicationContext) {
return new SpringHandlerInstantiator(applicationContext.getAutowireCapableBeanFactory());
}
}
#Configuration
public class RestConfiguration implements RepositoryRestConfigurer {
#Autowired
private Validator validator;
#Autowired
private HandlerInstantiator handlerInstantiator;
#Override
public void configureValidatingRepositoryEventListener(ValidatingRepositoryEventListener validatingListener) {
validatingListener.addValidator("beforeCreate", validator);
validatingListener.addValidator("beforeSave", validator);
}
#Override
public void configureJacksonObjectMapper(ObjectMapper objectMapper) {
objectMapper.setHandlerInstantiator(handlerInstantiator);
}
}
#Component
public class RestResourceURLSerializer extends JsonDeserializer<Long> {
#Autowired
private MyConfig config;
#Override
public Long deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
ServiceConfig serviceConfig = config.getServices().get("identity");
URI serviceUri = serviceConfig.getExternalUrl();
String servicePath = serviceUri.getPath();
URL givenUrl = p.readValueAs(URL.class);
String givenPath = givenUrl.getPath();
if (servicePath.equals(givenPath)) {
return Long.parseLong(givenPath.substring(givenPath.lastIndexOf('/') + 1));
}
return null;
}
}
I keep getting a NullPointerException POSTing something to the API endpoint that is deserialized with the JsonDeserializer above.
I was able to solve a similar problem by marking my deserializer constructor accept a parameter (and therefore removing the empty constructor) and marking constructor as #Autowired.
public class MyDeserializer extends JsonDeserializer<MyEntity> {
private final MyBean bean;
// no default constructor
#Autowired
public MyDeserializer(MyBean bean){
this.bean = bean
}
...
}
#JsonDeserialize(using = MyDeserializer.class)
public class MyEntity{...}
My entity is marked with annotation #JsonDeserialize so I don't have to explicitly register it with ObjectMapper.
There have been several arguments around not using ApplicationContext.getBean() to get a bean reference, of which most are based on logic that it violates the principles of Inversion of control.
Is there a way to get reference to prototype scoped bean without calling context.getBean() ?
Consider to use Spring Boot!
Than you can do something like this...
Runner:
#SpringBootApplication
public class Runner{
public static void main(String[] args) {
SpringApplication.run(Runner.class, args);
}
}
Some Controller:
#Controller
public class MyController {
// Spring Boot injecting beans through #Autowired annotation
#Autowired
#Qualifier("CoolFeature") // Use Qualifier annotation to mark a class, if for example
// you have more than one concreate class with differant implementations of some interface.
private CoolFeature myFeature;
public void testFeature(){
myFeature.doStuff();
}
}
Some cool feature:
#Component("CoolFeature") // To identify with Qualifier
public class CoolFeature{
#Autowired
private SomeOtherBean utilityBean;
public void doStuff(){
// use utilityBean in some way
}
}
No XML files to handle.
We can still access context for manual configurations if needed.
Suggested reading:
Spring Boot Reference
Pro Spring Boot
This type of problem can be solved using method injection, which is described in more detail here: https://docs.spring.io/spring/docs/current/spring-framework-reference/html/beans.html#beans-factory-method-injection
This is the most common approach to create prototype bean:
abstract class MyService {
void doSome() {
OtherService otherService = getOtherService();
}
abstract OtherService getOtherService();
}
#Configuration
class Config {
#Bean
public MyService myService() {
return new MyService() {
OtherService getOtherService() {
return otherService();
}
}
}
#Bean
#Scope("prototype")
public OtherService otherService() {
return new OtherService();
}
}
I have been trying to create a spring boot application. In my application I would like to add some custom methods to save the data instead of using the default save method.
My application entry point is something like this:
#Configuration
#ComponentScan
#EnableJpaRepositories(repositoryImplementationPostfix = "CustomImpl")
#Import(RepositoryRestMvcConfiguration.class)
#EnableAutoConfiguration
#PropertySource("application.properties")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
I have changed this line repositoryImplementationPostfix to even Impl but, it didn't work.
My CrudRepository
#RepositoryRestResource
public interface TaRepository extends CrudRepository<Ta, Integer> ,TestRepository{
List<Ta> findByName(#Param("name") String name);
}
My Custom Repository:
public interface TestRepository {
public void myCustomMethod(TestDto dto);
}
My Custom Repository Impl
public class TestRepositoryCustomImpl implements TestRepository{
#PersistenceContext
private EntityManager em;
#Override
public void myCustomMethod(TestDto model){
}
NOTE:
If I change my CrudRepostory from the mentioned to this:
#RepositoryRestResource
public interface TaRepository extends CrudRepository<Ta, Integer> {
List<Ta> findByName(#Param("name") String name);
}
everything works fine. But not with the custom method implementation.
For Spring Data JPA #Repository or #RepositoryRestResource you never need to implement a Custom Interface. For any simple query you can create any kind of method, please follow the simple guide.
http://docs.spring.io/spring-data/jpa/docs/1.4.1.RELEASE/reference/html/jpa.repositories.html
For a complex query you can use JpaSpecificationExecutor.
How can I create a Predicate from a HQL query?
I'm a Spring rookie and trying to benefit from the advantages of the easy 'profile' handling of Spring. I already worked through this tutorial: https://spring.io/blog/2011/02/14/spring-3-1-m1-introducing-profile and now I'd like to adapt that concept to an easy example.
I've got two profiles: dev and prod. I imagine a #Configuration class for each profile where I can instantiate different beans (implementing a common interface respectively) depending on the set profile.
My currently used classes look like this:
StatusController.java
#RestController
#RequestMapping("/status")
public class StatusController {
private final EnvironmentAwareBean environmentBean;
#Autowired
public StatusController(EnvironmentAwareBean environmentBean) {
this.environmentBean = environmentBean;
}
#RequestMapping(method = RequestMethod.GET)
Status getStatus() {
Status status = new Status();
status.setExtra("environmentBean=" + environmentBean.getString());
return status;
}
}
EnvironmentAwareBean.java
public interface EnvironmentAwareBean {
String getString();
}
EnvironmentAwareBean.java
#Service
public class DevBean implements EnvironmentAwareBean {
#Override
public String getString() {
return "development";
}
}
EnvironmentAwareBean.java
#Service
public class ProdBean implements EnvironmentAwareBean {
#Override
public String getString() {
return "production";
}
}
DevConfig.java
#Configuration
#Profile("dev")
public class DevConfig {
#Bean
public EnvironmentAwareBean getDevBean() {
return new DevBean();
}
}
ProdConfig.java
#Configuration
#Profile("prod")
public class ProdConfig {
#Bean
public EnvironmentAwareBean getProdBean() {
return new ProdBean();
}
}
Running the example throws this exception during startup (SPRING_PROFILES_DEFAULT is set to dev):
(...) UnsatisfiedDependencyException: (...) nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [EnvironmentAwareBean] is defined: expected single matching bean but found 3: prodBean,devBean,getDevBean
Is my approach far from a recommended configuration? In my opinion it would make more sense to annotate each Configuration with the #Profile annotation instead of doing it for each and every bean and possibly forgetting some variants when new classes are added later on.
Your implementations of EnvironmentAwareBean are all annotated with #Service.
This means they will all be picked up by component scanning and hence you get more than one matching bean. Do they need to be annotated with #Service?
Annotating each #Configuration with the #Profile annotation is fine. Another way as an educational exercise would be to not use #Profile and instead annotate the #Bean or Config classes with your own implementation of #Conditional.
I'm trying to build a Spring 3.1 PropertySource which reads its values from Zookeeper nodes. For connecting to Zookeeper I am using Curator from Netflix.
For that I've built a custom property source which reads the value of a property from Zookeeper and returns it. This works fine when I am resolving the property like this
ZookeeperPropertySource zkPropertySource = new ZookeeperPropertySource(zkClient);
ctx.getEnvironment().getPropertySources().addLast(zkPropertySource);
ctx.getEnvironment().getProperty("foo"); // returns 'from zookeeper'
However, when I try to instantiate a bean which has a field with an #Value annotation then this fails:
#Component
public class MyBean {
#Value("${foo}") public String foo;
}
MyBean b = ctx.getBean(MyBean.class); // fails with BeanCreationException
This problem has most likely nothing to do with Zookeeper but with the way I'm registering the property sources and creating the beans.
Any insight is highly appreciated.
Update 1:
I'm creating the app context from an XML file like this:
public class Main {
public static void main(String[] args) throws Exception {
ConfigurableApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
ctx.registerShutdownHook();
}
}
The class which connects to Zookeeper is a #Component.
#Component
public class Server {
CuratorFramework zkClient;
public void connectToZookeeper() {
zkClient = ... (curator magic) ...
}
public void registerPropertySource() {
ZookeeperPropertySource zkPropertySource = new ZookeeperPropertySource(zkClient);
ctx.getEnvironment().getPropertySources().addLast(zkPropertySource);
ctx.getEnvironment().getProperty("foo"); // returns 'from zookeeper'
}
#PostConstruct
public void start() {
connectToZookeeper();
registerPropertySource();
MyBean b = ctx.getBean(MyBean.class);
}
}
Update 2
This seems to work when I'm using XML-less configuration, i.e. #Configuration, #ComponentScan and #PropertySource in combination with an AnnotationConfigApplicationContext. Why doesn't it work with a ClassPathXmlApplicationContext?
#Configuration
#ComponentScan("com.goleft")
#PropertySource({"classpath:config.properties","classpath:version.properties"})
public class AppConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Answering to your Update 2: This does not work with your original configuration(registering a PropertySource using #PostConstruct) because the PropertySource is being registered very late, by this time your target bean has already been constructed and initialized.
Typically the injection of the placeholders happens via a BeanFactoryPostProcessor which is very early in the Spring lifecycle(beans have not been created at this stage) and if a PropertySource is registered at that stage, then placeholders should be resolved.
The best approach though is to use a ApplicationContextInitializer, get a handle on the applicationContext and to register the propertySource there:
public class CustomInitializer implements ApplicationContextInitializer<ConfigurableWebApplicationContext> {
public void initialize(ConfigurableWebApplicationContext ctx) {
ZookeeperPropertySource zkPropertySource = new ZookeeperPropertySource(zkClient);
ctx.getEnvironment().getPropertySources().addFirst(zkPropertySource);
}
}