I have a small service on SpringBoot and Mongodb as a DB.
I need to be able create a small collection with one document ( very basic: id, name, status) on startup. An analog of sql create table if not exists, but for mongo. How do I do that?
I tried to initialize values in the document attributes, but it didn't help.
Currently, collection and the document appear only if I use API to add it.
You may want to use something like ApplicationRunner or CommandLineRunner which can be defined as a bean.
Example:
#SpringBootApplication
public class MyApplication {
public static void main(String[] args) {
SpringApplication.run(MyApplication .class, args);
}
#Bean
public CommandLineRunner initialize(MyRepository myRepository) {
return args -> {
// Insert elements into myRepository
};
}
}
Both CommandLineRunner and ApplicationRunner are functional interfaces, so we can use a lambda for them. Spring Boot will execute them at the startup of the application.
You can leverage the spring internal event mechanism.
When your application is ready, spring triggers the event ApplicationReadyEvent
You can listen to this event and init your collection:
#Component
public class DataInit implements ApplicationListener<ApplicationReadyEvent> {
private final MyRepository myRepository;
public DataInit(MyRepository myRepository) {
this.myRepository = myRepository;
}
#Override
public void onApplicationEvent(ApplicationReadyEvent event) {
// init data
}
}
Related
I want to read text data fixtures (CSV files) at the start on my application and put it in my database.
For that, I have created a PopulationService with an initialization method (#PostConstruct annotation).
I also want them to be executed in a single transaction, and hence I added #Transactional on the same method.
However, the #Transactional seems to be ignored :
The transaction is started / stopped at my low level DAO methods.
Do I need to manage the transaction manually then ?
Quote from legacy (closed) Spring forum:
In the #PostConstruct (as with the afterPropertiesSet from the InitializingBean interface) there is no way to ensure that all the post processing is already done, so (indeed) there can be no Transactions. The only way to ensure that that is working is by using a TransactionTemplate.
So if you would like something in your #PostConstruct to be executed within transaction you have to do something like this:
#Service("something")
public class Something {
#Autowired
#Qualifier("transactionManager")
protected PlatformTransactionManager txManager;
#PostConstruct
private void init(){
TransactionTemplate tmpl = new TransactionTemplate(txManager);
tmpl.execute(new TransactionCallbackWithoutResult() {
#Override
protected void doInTransactionWithoutResult(TransactionStatus status) {
//PUT YOUR CALL TO SERVICE HERE
}
});
}
}
I think #PostConstruct only ensures the preprocessing/injection of your current class is finished. It does not mean that the initialization of the whole application context is finished.
However you can use the spring event system to receive an event when the initialization of the application context is finished:
public class MyApplicationListener implements ApplicationListener<ContextRefreshedEvent> {
public void onApplicationEvent(ContextRefreshedEvent event) {
// do startup code ..
}
}
See the documentation section Standard and Custom Events for more details.
As an update, from Spring 4.2 the #EventListener annotation allows a cleaner implementation:
#Service
public class InitService {
#Autowired
MyDAO myDAO;
#EventListener(ContextRefreshedEvent.class)
public void onApplicationEvent(ContextRefreshedEvent event) {
event.getApplicationContext().getBean(InitService.class).initialize();
}
#Transactional
public void initialize() {
// use the DAO
}
}
Inject self and call through it the #Transactional method
public class AccountService {
#Autowired
private AccountService self;
#Transactional
public void resetAllAccounts(){
//...
}
#PostConstruct
private void init(){
self.resetAllAccounts();
}
}
For older Spring versions which do not support self-injection, inject BeanFactory and get self as beanFactory.getBean(AccountService.class)
EDIT
It looks like that since this solution has been posted 1.5 years ago developers are still under impression that if a method,
annotated with #Transactional, is called from a #PostContruct-annotated method invoked upon the Bean initialization, it won't be actually executed inside of Spring Transaction, and awkward (obsolete?) solutions get discussed and accepted instead of this very simple and straightforward one and the latter even gets downvoted.
The Doubting Thomases :) are welcome to check out an example Spring Boot application at GitHub which implements the described above solution.
What actually causes, IMHO, the confusion: the call to #Transactional method should be done through a proxied version of a Bean where such method is defined.
When a #Transactional method is called from another Bean, that another Bean usually injects this one and invokes its proxied (e.g. through #Autowired) version of it, and everything is fine.
When a #Transactional method is called from the same Bean directly, through usual Java call, the Spring AOP/Proxy machinery is not involved and the method is not executed inside of Transaction.
When, as in the suggested solution, a #Transactional method is called from the same Bean through self-injected proxy (self field), the situation is basically equivalent to a case 1.
#Platon Serbin's answer didn't work for me. So I kept searching and found the following answer that saved my life. :D
The answer is here No Session Hibernate in #PostConstruct, which I took the liberty to transcribe:
#Service("myService")
#Transactional(readOnly = true)
public class MyServiceImpl implements MyService {
#Autowired
private MyDao myDao;
private CacheList cacheList;
#Autowired
public void MyServiceImpl(PlatformTransactionManager transactionManager) {
this.cacheList = (CacheList) new TransactionTemplate(transactionManager).execute(new TransactionCallback(){
#Override
public Object doInTransaction(TransactionStatus transactionStatus) {
CacheList cacheList = new CacheList();
cacheList.reloadCache(MyServiceImpl.this.myDao.getAllFromServer());
return cacheList;
}
});
}
The transaction part of spring might not be initialized completely at #PostConstruct.
Use a listener to the ContextRefreshedEvent event to ensure, that transactions are available:
#Component
public class YourService
implements ApplicationListener<ContextRefreshedEvent> // <= ensure correct timing!
{
private final YourRepo repo;
public YourService (YourRepo repo) {this.repo = repo;}
#Transactional // <= ensure transaction!
#Override
public void onApplicationEvent(ContextRefreshedEvent event) {
repo.doSomethingWithinTransaction();
}
}
Using transactionOperations.execute() in #PostConstruct or in #NoTransaction method both works
#Service
public class ConfigurationService implements ApplicationContextAware {
private static final Logger LOG = LoggerFactory.getLogger(ConfigurationService.class);
private ConfigDAO dao;
private TransactionOperations transactionOperations;
#Autowired
public void setTransactionOperations(TransactionOperations transactionOperations) {
this.transactionOperations = transactionOperations;
}
#Autowired
public void setConfigurationDAO(ConfigDAO dao) {
this.dao = dao;
}
#PostConstruct
public void postConstruct() {
try { transactionOperations.execute(new TransactionCallbackWithoutResult() {
#Override
protected void doInTransactionWithoutResult(final TransactionStatus status) {
ResultSet<Config> configs = dao.queryAll();
}
});
}
catch (Exception ex)
{
LOG.trace(ex.getMessage(), ex);
}
}
#NoTransaction
public void saveConfiguration(final Configuration configuration, final boolean applicationSpecific) {
String name = configuration.getName();
Configuration original = transactionOperations.execute((TransactionCallback<Configuration>) status ->
getConfiguration(configuration.getName(), applicationSpecific, null));
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
}
}
I need to implement Spring boot - MongoDb application where There are 2 mongo DBs which have exact same database name & collections. Based on User making a request, i need to choose whether to fetch data from DB1 or DB2 (only difference in mongo URI host - IP).
E.g. I need some way to create 2 mongoTemplates like mTempA & mTempB in my Repository & based on some condition, use either of the template to execute query as below:
#Repository
public class MyCustomRepository {
private Logger logger = LoggerFactory.getLogger(MyCustomRepository.class);
#Autowired
private MongoTemplateA mongoTemplateA;// Need to know if this is possible & how
#Autowired
private MongoTemplateB mongoTemplateB;// Need to know if this is possible & how
public List<MyModel> findByCriteria(MyRequest request) {
List<MyModel> result;
//Query query = <build query based on request>
if (request.getUserType().equals("A")) {
result = mongoTemplateA.find(query, MyModel.class);
} else {
result = mongoTemplateB.find(query, MyModel.class);
}
logger.debug("Result fetched with {} records", result.size());
return result;
}
}
I don't want to have 2 separate Repo (Class or Interfaces) or different models to be used. Just want to have 2 different mongoTemplates to be injected in single repo.
Is this possible? If yes, please give some example code.
I have followed below tutorial:
https://dzone.com/articles/multiple-mongodb-connectors-with-spring-boot
As rightly pointed out by #Lucia, below is how it can be done:
Have 2 different configuration placeholders
#Configuration
#EnableMongoRepositories(basePackages = "com.snk.repository", mongoTemplateRef = "mongoTemplateA")
public class MongoConfigA {
// Configuration class for DB 1 access
}
#Configuration
#EnableMongoRepositories(basePackages = "com.snk.repository", mongoTemplateRef = "mongoTemplateB")
public class MongoConfigB {
// Configuration class for DB 2 access
}
Get one class which will help in reading custom properties for mongo db properties in application.properties:
#ConfigurationProperties(prefix = "mongodb")
public class MultipleMongoProperties {
private MongoProperties adb = new MongoProperties();
private MongoProperties bdb = new MongoProperties();
public MongoProperties getAdb() {
return adb;
}
public MongoProperties getBdb() {
return bdb;
}
}
Add a configuration class to create mongoTemplates:
#Configuration
#EnableConfigurationProperties(MultipleMongoProperties.class)
public class MultipleMongoConfig {
#Autowired
private MultipleMongoProperties mongoProperties = new MultipleMongoProperties();
#Bean(name = "mongoTemplateA")
#Primary
public MongoTemplate mongoTemplateA() {
return new MongoTemplate(aDbFactory(this.mongoProperties.getAdb()));
}
#Bean(name = "mongoTemplateB")
public MongoTemplate mongoTemplateB() {
return new MongoTemplate(bDbFactory(this.mongoProperties.getBdb()));
}
#Bean
#Primary
public MongoDbFactory aDbFactory(final MongoProperties mongo) {
return new SimpleMongoDbFactory(new MongoClientURI(mongo.getUri()));
}
#Bean
public MongoDbFactory bDbFactory(final MongoProperties mongo) {
return new SimpleMongoDbFactory(new MongoClientURI(mongo.getUri()));
}
}
Add below decelerations to your service/repository:
#Autowired
#Qualifier("mongoTemplateA")
private MongoTemplate mongoTemplateA;
#Autowired
#Qualifier("MongoTemplateB")
private MongoTemplate MongoTemplateB;
Add below properties in your application.properties:
mongodb.adb.uri=mongodb://user:pass#myhost1:27017/adb
mongodb.bdb.uri=mongodb://user:pass#myhost2:27017/bdb
If you have mongo rplica set, URL can be set as:
mongodb.adb.uri=mongodb://user:pass#myhost1,myhost2,myhost13/adb?replicaSet=rsName
mongodb.bdb.uri=mongodb://user:pass#myhost1,myhost2,myhost13/bdb?replicaSet=rsName
Based on your logic, use either of the template.
Thought, there are few catches:
Notice the #Primary annotation, one bean needs to be marked as primary. I haven't find any solution if no template is marked primary.
If any of the mongo DB is down & application is started/restarted, application will not start/deploy. to avoid this, #Autowired needs to be changed to #Autowired(required = false).
If any of the mongo DB is down & application is already running, it automatically uses 2nd mongo BD (which is not down). So, even if you want to use A DB, if it's down, requests are processed with B DB & vice-versa.
I am trying to write an extension for JUnit 5 and was curious if there is a way for me to tap into the mongodb connection that #SpringBootTest already set up for the test.
So, for example, my extension looks like this:
public class MyExtension implements BeforeTestExecutionCallback {
#Override
public void beforeTestExecution(ExtensionContext context) throws Exception {
// How do I get at the MongoClient here (or in the class constructor)?
}
}
I can create a new one, of course, but I'd like to reuse the one Spring already set up so the extension won't have to deal with knowing information like URI, auth credentials, etc.
Any ideas?
SpringExtension class provides a method for getting ApplicationContext associated with the supplied ExtensionContext.
Then you can get the bean from the ApplicationContext like this:
public class MyExtension implements BeforeTestExecutionCallback {
#Override
public void beforeTestExecution(ExtensionContext context) throws Exception {
ApplicationContext applicationContext = SpringExtension.getApplicationContext(context);
MongoClient mongoClient = applicationContext.getBean(MongoClient.class);
}
}
I was learning Spring Data Rest but I didn't find how to use Cache in Spring Data Rest.
How can i use Cache with Spring Data Rest's curd/page .
Or should I use JPA+Cache and ignore Spring Data Rest?
If I misunderstanding anything please remind me.
best regard
You can try the following approach:
1) Override your repos methods findById and findAll, make them Cacheable:
public interface MyEntityRepo extends JpaRepository<MyEntity, Long> {
#Cacheable("myEntities")
#Override
Optional<MyEntity> findById(Long id);
#Cacheable("pagedMyEntities")
#Override
Page<MyEntity> findAll(Pageable pageable);
}
2) Create a RepositoryEventHandler to evict your caches:
#RepositoryEventHandler
public class MyEntityEventHandler {
private final CacheManager cacheManager;
public MyEntityEventHandler(CacheManager cacheManager) {
this.cacheManager = cacheManager;
}
#HandleAfterCreate
#HandleAfterSave
#HandleAfterDelete
public void handleCachesEviction(MyEntity entity) {
Optional.ofNullable(cacheManager.getCache("myEntities"))
.ifPresent(c -> c.evict(entity.getId()));
Optional.ofNullable(cacheManager.getCache("pagedMyEntities"))
.ifPresent(c -> c.clear());
}
}
3) And of course create a cache manager bean, for example:
#EnableCaching
#SpringBootApplication
public class Application {
#Bean
public CacheManager cacheManager() {
return new ConcurrentMapCacheManager();
}
}
According to the samples here (actually - timestamp task), I have implemented a small task class:
#SpringBootApplication
#EnableTask
#EnableConfigurationProperties({ RestProcessorTaskProperties.class })
public class RestProcessorTaskApplication {
public static void main(String[] args) {
SpringApplication.run(RestProcessorTaskApplication.class, args);
}
#Autowired
private RestProcessorTaskProperties config;
// some fields and beans
#Bean
public CommandLineRunner run(RestTemplate restTemplate) {
return args -> {
// doing some stuff
};
}
}
and then I've created Properties class (in the same package)
#ConfigurationProperties("RestProcessor")
public class RestProcessorTaskProperties {
private String host = "http://myhost:port";
public String getHost() {
return host;
}
public void setHost(String host) {
this.host = host;
}
}
But after I've registered task on my local Spring Cloud Data Server, I see numerous parameters, that, I suppose, was added automatically. I those mean parameters like:
abandon-when-percentage-full java.lang.Integer
abandoned-usage-tracking java.lang.Boolean
acceptors java.lang.Integer
access-to-underlying-connection-allowed java.lang.Boolean
and others...
Is it possible somehow to hide (or remove) them, so that when launching task I could configure only those parameters, that was added by me (single host property in my example above)?
By default Spring Cloud Data Flow will show you all the available properties for a boot application. However, you can create a whitelist of properties that you wish to show.
Here is a link to the Spring Cloud Data Flow reference doc that will discuss how to do this: http://docs.spring.io/spring-cloud-dataflow/docs/current/reference/htmlsingle/#spring-cloud-dataflow-stream-app-whitelisting.
And here is link to the timestamp starter app that has an example of this: https://github.com/spring-cloud/spring-cloud-task-app-starters/tree/master/spring-cloud-starter-task-timestamp