Injecting configuration dependency - spring

I am creating a cache client wrapper using spring framework. This is to provide cache layer to our application. Right now, we are using redis. I have found out that spring-data-redis library is very good for creating my wrapper.
My application will pass a configuration POJO to my wrapper and will then use the interface that I will provide.
spring-data-redis provides an easy way to access redis using two variables.
RedisConnectionFactory
RedisTemplate<String, Object>
Although, I will be providing a better interface to my application with my interface functions like:
public Object getValue( final String key ) throws ConfigInvalidException;
public void setValue( final String key, final Object value ) throws ConfigInvalidException;
public void setValueWithExpiry(final String key, final Object value, final int seconds, final TimeUnit timeUnit) throws ConfigInvalidException;
I still want to provide RedisConnectionFactory and RedisTemplate beans.
My question is how to initialize my wrapper application with this configuration POJO?
Currently my configuration looks like this:
import java.util.List;
public class ClusterConfigurationProperties {
List<String> nodes;
public List<String> getNodes() {
return nodes;
}
public void setNodes(List<String> nodes) {
this.nodes = nodes;
}
}
And my AppConfig.java looks like this:
import com.ajio.Exception.ConfigInvalidException;
import com.ajio.configuration.ClusterConfigurationProperties;
import com.ajio.validator.Validator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericToStringSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
#Configuration
public class AppConfig {
#Autowired
private ClusterConfigurationProperties clusterConfigurationProperties;
#Autowired
private Validator validator;
#Bean
ClusterConfigurationProperties clusterConfigurationProperties() {
return null;
}
#Bean
Validator validator() {
return new Validator();
}
#Bean
RedisConnectionFactory connectionFactory() throws ConfigInvalidException {
if (clusterConfigurationProperties == null)
throw new ConfigInvalidException("Please provide a cluster configuration POJO in context");
validator.validate(clusterConfigurationProperties);
return new JedisConnectionFactory(new RedisClusterConfiguration(clusterConfigurationProperties.getNodes()));
}
#Bean
RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) throws ConfigInvalidException {
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(connectionFactory());
redisTemplate.setKeySerializer( new StringRedisSerializer() );
redisTemplate.setHashValueSerializer( new GenericToStringSerializer<>( Object.class ) );
redisTemplate.setValueSerializer( new GenericToStringSerializer<>( Object.class ) );
return redisTemplate;
}
}
Here I am expecting a ClusterConfigurationProperties POJO as a bean in application which will be using the interface of wrapper.
But to compile my wrapper, I have created a null bean itself. Then when application uses it, there will be two beans, one of application and one of wrapper.
How should I resolve this problem?

Actually what i wanted was to have cluster config as a bean in my client application. For that i dont need to declare #autowire clusterconfig in my wrapper application. Instead should take cluster config as a parameter in the method, so that the client will pass cluster config object when creating bean. And the bean which is created in client code should have code for creating redis connection factory.
But all this i was writing was to make my client unknown of redis. So, better solution is to have wrapper class which takes cluster config pojo and create redis connection factory etc. And client should create this wrapper as a bean.
Very poor concept of spring and design patterns lead me to this mistake.

Related

Reading same cache from different microservices

Am using spring-data-redis(2.1.5.RELEASE) and jedis(2.10.2) client to connect to my azure redis instance from different services running as spring-boot application.
Two services has the same caching methods and pointed to the same cache by implementing the following configuration. The problem am facing is when one service trying to read a cached value created by another service, de-seralization exception occurs.
Exception:
org.springframework.data.redis.serializer.SerializationException: Cannot deserialize; nested exception is org.springframework.core.serializer.support.SerializationFailedException: Failed to deserialize payload. Is the byte array a result of corresponding serialization for DefaultDeserializer?; nested exception is org.springframework.core.NestedIOException: Failed to deserialize object type; nested exception is java.lang.ClassNotFoundException
Note: Am using redis only to cache the data read from my database.
Redis Cache Configuration of microservice 1
public RedisCacheWriter redisCacheWriter(RedisConnectionFactory connectionFactory) {
return RedisCacheWriter.nonLockingRedisCacheWriter(connectionFactory);
}
#Bean
public RedisCacheManager cacheManager() {
Map<String, RedisCacheConfiguration> cacheNamesConfigurationMap = new HashMap<>();
cacheNamesConfigurationMap.put("employers", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofSeconds(90000)));
cacheNamesConfigurationMap.put("employees", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofSeconds(90000)));
RedisCacheManager manager = new RedisCacheManager(redisCacheWriter(), RedisCacheConfiguration.defaultCacheConfig(), cacheNamesConfigurationMap);
manager.setTransactionAware(true);
manager.afterPropertiesSet();
return manager;
}
Redis Cache Configuration of microservice 2
public RedisCacheWriter redisCacheWriter(RedisConnectionFactory connectionFactory) {
return RedisCacheWriter.nonLockingRedisCacheWriter(connectionFactory);
}
#Bean
public RedisCacheManager cacheManager() {
Map<String, RedisCacheConfiguration> cacheNamesConfigurationMap = new HashMap<>();
cacheNamesConfigurationMap.put("employees", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofSeconds(90000)));
RedisCacheManager manager = new RedisCacheManager(redisCacheWriter(), RedisCacheConfiguration.defaultCacheConfig(), cacheNamesConfigurationMap);
manager.setTransactionAware(true);
manager.afterPropertiesSet();
return manager;
}
Caching methods in both services
#Cacheable(value = "employees", key = "#employeesId")
public Employee getEmployee(String employeesId) {
//methods
}
Employee class in both services
public class Employee implements Serializable {
private String id;
private String name;
}
Either make sure the returned (de(serialized)) object is in exact same package or prevent registering the class in the data. This happens because the class name with full package qualified name are set into the data (JSON in my case). Here are the configuration I used to
Do not get restricted using same class name of a dto !
Use typed de-(serialization) and not generic types for converting from/to JSON
Remove the class mark put in the data
import lombok.RequiredArgsConstructor;
import org.springframework.boot.autoconfigure.cache.RedisCacheManagerBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext.SerializationPair;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;
#Configuration
#RequiredArgsConstructor
public class RedisConfig {
#Bean
RedisCacheManagerBuilderCustomizer redisCacheManagerBuilderCustomizer() {
return builder -> {
Map<String, RedisCacheConfiguration> configurationMap = new HashMap<>();
configurationMap.put("whatever-cache-name",
RedisCacheConfiguration.defaultCacheConfig()
.entryTtl(Duration.ofSeconds(3600))
.serializeValuesWith(
SerializationPair.fromSerializer(new Jackson2JsonRedisSerializer<>(Employee.class))
)
);
builder.withInitialCacheConfigurations(configurationMap);
};
}
}
To only
Remove the class mark put in the data
Just use instead a different serializer
#AutoWired
ObjectMapper objectMapper;
#Bean
RedisCacheManagerBuilderCustomizer redisCacheManagerBuilderCustomizer() {
return builder -> {
Map<String, RedisCacheConfiguration> configurationMap = new HashMap<>();
configurationMap.put("whatever-cache-name",
RedisCacheConfiguration.defaultCacheConfig()
.entryTtl(Duration.ofSeconds(3600))
.serializeValuesWith(
SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer(objectMapper))
)
);
builder.withInitialCacheConfigurations(configurationMap);
};
}
Note that by default the GenericJackson2JsonRedisSerializer creates new ObjectMapper if you don't provide one in the constructor and the default implementation will add the full qualified class name in the data and that's why I used the one provided by Spring as it was properly configured enough in that case.
I would suggest you make sure the Employee classes are identical and then add a serialVersionUID field to the classes. Clear the Redis cache and try again.
This is from the Javadocs in the java.io.Serializable interface:
If a serializable class does not explicitly declare a serialVersionUID, then
the serialization runtime will calculate a default serialVersionUID value
for that class based on various aspects of the class, as described in the
Java(TM) Object Serialization Specification. However, it is strongly
recommended that all serializable classes explicitly declare
serialVersionUID values, since the default serialVersionUID computation is
highly sensitive to class details that may vary depending on compiler
implementations, and can thus result in unexpected
InvalidClassExceptions during deserialization. Therefore, to
guarantee a consistent serialVersionUID value across different java compiler
implementations, a serializable class must declare an explicit
serialVersionUID value. It is also strongly advised that explicit
serialVersionUID declarations use the private modifier where
possible, since such declarations apply only to the immediately declaring
class--serialVersionUID fields are not useful as inherited members.

Multiple RedisConnectionFactories in Spring Boot Application

My application uses one "main" redis instance for things like session storage and cache but needs to talk to a separate "external" instance for other reasons. I am trying to determine the "best" ("most idiomatic"? "simplest"?) way to configure this in my Spring Boot application.
Ideally I'd just like to use the default auto-configuration for the main instance but as soon as I register a connection factory for the external instance the #ConditionalOnMissngBean({RedisConnectionFactory.class}) condition in LettuceConnectionConfiguration becomes false and so the default instance isn't created. Looking at what else is going on in LettuceConnectionConfiguration etc. I feel like I'd rather not manually configure it if I don't need to.
I could just not expose the "external" connection factory as a bean and only use it internally to create the beans that depend on it but, while that would be ok in my specific case, I'd like to understand if there's a better solution where both factories can be exposed.
Is there some way I can expose the second RedisConnectionFactory without disabling the default one provided by auto configuration? Is there a clear "right way" to do this sort of thing?
you must implement the BeanDefinitionRegistryPostProcessor to adjust the RedisConnectionFactory order
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.stereotype.Component;
#Component
public class MultipleRedisConnectionFactoryRegistrar implements BeanDefinitionRegistryPostProcessor {
#Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
BeanDefinition bd1 = registry.getBeanDefinition("redisConnectionFactory");
if (bd1 != null) {
BeanDefinition bd = new RootBeanDefinition(ExternalRedisConnectionFactoryBean.class);
registry.registerBeanDefinition("externalRedisConnectionFactory", bd);
}
}
#Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
}
}
in ExternalRedisConnectionFactoryBean, you can create your own RedisConnectionFactory
import org.springframework.beans.factory.FactoryBean;
import org.springframework.data.redis.connection.RedisConnectionFactory;
public class ExternalRedisConnectionFactoryBean implements FactoryBean<RedisConnectionFactory> {
#Override
public RedisConnectionFactory getObject() throws Exception {
//you can mannually create your external redis connection factory here
return null;
}
#Override
public Class<?> getObjectType() {
return RedisConnectionFactory.class;
}
}
if you want to use the multiple RedisConnectionFactory, you #Qualifier is the right choice, for example
#Autowired
#Qualifier("redisConnectionFactory")
private RedisConnectionFactory defaultRedisConnectionFactory;
#Autowired
#Qualifier("externalRedisConnectionFactory")
private RedisConnectionFactory externalRedisConnectionFactory;

Enabling Redis cache in spring boot

I have following configuration on my spring boot project.
#SpringBootApplication
#EnableTransactionManagement
#EnableCaching
#EnableScheduling
#EnableAsync
public class Application {
String redisHost = "localhost";
int redisPort = 6379;
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
#Bean
JedisConnectionFactory jedisConnectionFactory() {
JedisConnectionFactory factory = new JedisConnectionFactory();
factory.setHostName(redisHost);
factory.setPort(redisPort);
factory.setUsePool(true);
return factory;
}
#Bean
RedisTemplate<Object, Object> redisTemplate() {
RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<Object, Object>();
redisTemplate.setConnectionFactory(jedisConnectionFactory());
return redisTemplate;
}
#Bean
public CacheManager cacheManager() {
RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate());
return cacheManager;
}
}
Also I have following maven dependency on pom.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
I have a separate redis server running on my local machine on defined port. Also in my service classes I have annotations like #Cacheable, #CachePut to support caching.
I can start spring boot application without errors and CRUD operations also works. But seems it is not using the defined redis cache. I used 'redi desktop manger' browsing tool and couldn't find any data on redis. Also I tried with monitoring redis server via redis cli command 'monitor', I can't see any changes on monitor.
So I assume redis caching still not working on my spring boot application. Can someone help me to figure out the issue?
I am using spring boot version 1.4.2.RELEASE
Thanks!
Given you are using Spring Boot, much of your Redis configuration is unnecessary since Spring Boot provides "auto-configuration" support for Redis, both as a data source as well as a caching provider.
You were also not specific about what version of Spring Boot you were using (e.g. 1.5.0.RC1) to run your application, or whether you had any application.properties on your application's classpath, which might make a difference if you explicitly specified spring.cache.type (set to something other than "redis", for instance).
However, in general, I cannot really see much wrong with your Redis or Spring Cache #Configuration class. However, it does seem to be a problem with not explicitly setting cacheManager.setUsePrefix(true). When I set this RedisCacheManager property ('usePrefix`), then everything worked as expected.
I am not (Spring Data) Redis expert so I am not exactly sure why this is needed. However, I based my test configuration on Spring Boot's "auto-configuration" support for Redis caching as well as your #Configuration "Application" class, shown above.
And, because you can eliminate most of your explicit configuration and use Spring Boot's "auto-configuration" support for Redis as a data source as well, I added a "AutoRedisConfiguration" #Configuration class to my test class. I.e. you can use this to configure Redis instead of my other #Configuration class ("CustomRedisConfiguration") which uses your configuration + the fix.
Here is the complete test example...
/*
* Copyright 2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.spring.cache;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.Arrays;
import java.util.Properties;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.annotation.PostConstruct;
import org.junit.Before;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.MethodSorters;
import org.spring.cache.CachingWithRedisIntegrationTest.CachingWithRedisConfiguration;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Profile;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.util.Assert;
/**
* Integration tests testing Spring's Cache Abstraction using Spring Data Redis auto-configured with Spring Boot.
*
* To run this test, first start a Redis Server on localhost listening on the default port, 6379.
*
* #author John Blum
* #see org.junit.Test
* #since 1.0.0
*/
#RunWith(SpringRunner.class)
#ActiveProfiles("auto")
#FixMethodOrder(MethodSorters.NAME_ASCENDING)
#ContextConfiguration(classes = CachingWithRedisConfiguration.class)
#SuppressWarnings("unused")
public class CachingWithRedisIntegrationTest {
protected static final int REDIS_PORT = 6379;
protected static final String REDIS_HOST = "localhost";
private AtomicBoolean setup = new AtomicBoolean(false);
#Autowired
private MathService mathService;
#Autowired(required = false)
private RedisTemplate<Object, Object> redisTemplate;
#Before
public void setup() {
if (redisTemplate != null && !setup.getAndSet(true)) {
redisTemplate.delete(Arrays.asList(0L, 1L, 2L, 4L, 8L));
}
}
#Test
public void firstCacheMisses() {
assertThat(mathService.factorial(0L)).isEqualTo(1L);
assertThat(mathService.wasCacheMiss()).isTrue();
assertThat(mathService.factorial(1L)).isEqualTo(1L);
assertThat(mathService.wasCacheMiss()).isTrue();
assertThat(mathService.factorial(2L)).isEqualTo(2L);
assertThat(mathService.wasCacheMiss()).isTrue();
assertThat(mathService.factorial(4L)).isEqualTo(24L);
assertThat(mathService.wasCacheMiss()).isTrue();
assertThat(mathService.factorial(8L)).isEqualTo(40320L);
assertThat(mathService.wasCacheMiss()).isTrue();
}
#Test
public void thenCacheHits() {
assertThat(mathService.factorial(0L)).isEqualTo(1L);
assertThat(mathService.wasCacheMiss()).isFalse();
assertThat(mathService.factorial(1L)).isEqualTo(1L);
assertThat(mathService.wasCacheMiss()).isFalse();
assertThat(mathService.factorial(2L)).isEqualTo(2L);
assertThat(mathService.wasCacheMiss()).isFalse();
assertThat(mathService.factorial(4L)).isEqualTo(24L);
assertThat(mathService.wasCacheMiss()).isFalse();
assertThat(mathService.factorial(8L)).isEqualTo(40320L);
assertThat(mathService.wasCacheMiss()).isFalse();
}
interface MathService {
boolean wasCacheMiss();
long factorial(long number);
}
#EnableCaching
#SpringBootConfiguration
#Import({ AutoRedisConfiguration.class, CustomRedisConfiguration.class })
static class CachingWithRedisConfiguration {
#Bean
MathService mathService() {
return new MathService() {
private final AtomicBoolean cacheMiss = new AtomicBoolean(false);
#Override
public boolean wasCacheMiss() {
return cacheMiss.getAndSet(false);
}
#Override
#Cacheable(cacheNames = "Factorials")
public long factorial(long number) {
cacheMiss.set(true);
Assert.isTrue(number >= 0L, String.format("Number [%d] must be greater than equal to 0", number));
if (number <= 2L) {
return (number < 2L ? 1L : 2L);
}
long result = number;
while (--number > 1) {
result *= number;
}
return result;
}
};
}
#Bean
#Profile("none")
CacheManager cacheManager() {
return new ConcurrentMapCacheManager();
}
}
#Profile("auto")
#EnableAutoConfiguration
#SpringBootConfiguration
static class AutoRedisConfiguration {
#PostConstruct
public void afterPropertiesSet() {
System.out.println("AUTO");
}
#Bean
static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer =
new PropertySourcesPlaceholderConfigurer();
propertySourcesPlaceholderConfigurer.setProperties(redisProperties());
return propertySourcesPlaceholderConfigurer;
}
static Properties redisProperties() {
Properties redisProperties = new Properties();
redisProperties.setProperty("spring.cache.type", "redis");
redisProperties.setProperty("spring.redis.host", REDIS_HOST);
redisProperties.setProperty("spring.redis.port", String.valueOf(REDIS_PORT));
return redisProperties;
}
}
#Profile("custom")
#SpringBootConfiguration
static class CustomRedisConfiguration {
#PostConstruct
public void afterPropertiesSet() {
System.out.println("CUSTOM");
}
#Bean
JedisConnectionFactory jedisConnectionFactory() {
JedisConnectionFactory factory = new JedisConnectionFactory();
factory.setHostName(REDIS_HOST);
factory.setPort(REDIS_PORT);
factory.setUsePool(true);
return factory;
}
#Bean
RedisTemplate<Object, Object> redisTemplate() {
RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(jedisConnectionFactory());
return redisTemplate;
}
#Bean
CacheManager cacheManager() {
RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate());
cacheManager.setUsePrefix(true); // THIS IS NEEDED!
return cacheManager;
}
}
}
Hope this helps!
Cheers,
John
I am using Spring Boot 2.0 and its very simple to use Redis for simple caching purpose.
Annotate your Spring boot application with #EnableCaching
In your application.properties have these properties
spring.cache.type=redis
redis.host.url=
redis.host.port=
Annotate your methods with #Cacheable.
That's it!!
If you are using AWS Elasticache and you have checked the in-transit encryption then you need to add a RedisConfiguration file to set your ssl to true.
Spring Boot 2.0 now uses LettuceConnectionFactory.
To do the above simply add a class and mark it with #Configuration annotation and add the following bean
#Bean
public LettuceConnectionFactory redisConnectionFactory() {
RedisStandaloneConfiguration configuration = new RedisStandaloneConfiguration();
configuration.setHostName(redisHost);
configuration.setPort(redisPort);
return new LettuceConnectionFactory(configuration, LettuceClientConfiguration.builder().useSsl().disablePeerVerification().build());
}
You can check existence of your keys in redis with command in redis-cli: keys *
If there will be your key, everything is OK :)
The methods of your classes should be #Cacheable. Along with #CachePut you should use #CacheEvict with the keys and their values for delete method to flush out the resources. Also the host, port, type and password is needed in application.properties file.
`spring.redis.password= password`
`spring.cache.type=redis`
`spring.redis.host=localhost`
`spring.redis.port=6379`
Also add some more properties like so, as per requirement.
`spring.cache.redis.time-to-live=600000`
`spring.cache.redis.cache-null-values=false`
`spring.cache.redis.use-key-prefix=true

How do I add beans dynamically in code in a Spring (Boot) application?

I have a Spring (boot) application that's using spring-rabbit, and I create the binding beans as needed like so:
import org.springframework.amqp.core.*;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class QueueBindings {
// first binding
#Bean
public Queue firstQueue(#Value("${rabbitmq.first.queue}") String queueName) {
return new Queue(queueName);
}
#Bean
public FanoutExchange firstExchange(#Value("${rabbitmq.first.exchange}") String exchangeName) {
return new FanoutExchange(exchangeName);
}
#Bean
public Binding firstBinding(Queue firstQueue, FanoutExchange firstExchange) {
return BindingBuilder.bind(firstQueue).to(firstExchange);
}
// second binding
#Bean
public Queue secondQueue(#Value("${rabbitmq.second.queue}") String queueName) {
return new Queue(queueName);
}
#Bean
public FanoutExchange secondExchange(#Value("${rabbitmq.second.exchange}") String exchangeName) {
return new FanoutExchange(exchangeName);
}
#Bean
public Binding secondBinding(Queue secondQueue, FanoutExchange secondExchange) {
return BindingBuilder.bind(secondQueue).to(secondExchange);
}
}
The issue I have is that there are only two pieces of information per 3 beans, the queue name and the exchange name.
Is there a way to add an arbitrary number of beans to the context rather than copy and paste a bunch of #Bean methods? I'd want something like "for each name in this list, add these three beans with this connection."
To register an arbitrary number of beans programatically, you need to drop down to a lower-level API. You can use #Import on a configuration class to reference an ImportBeanDefinitionRegistrar implementation. In the registerBeanDefinitions method of the registrar, you'd then register bean definitions for all of the beans.
If you want to be able to externally configure the beans that will be registered, an ImportBeanDefinitionRegistrar can be EnvironmentAware. This allows you to have the Environment injected so that you can use its properties to customise the beans that your registrar will register.

Loading properties using #Value into a BeanFactory object using #Bean in Spring Boot

Can anyone help me with a Spring Boot problem?
I want to create a factory bean as part of my application context but I want to be able to instantiate it with injected property values. However it seems that Spring will load FactoryBeans before anything else as demonstrated here:
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.beans.factory.config.AbstractFactoryBean;
import org.springframework.beans.factory.config.ListFactoryBean;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
#EnableAutoConfiguration
public class TestClass
{
#Value("${test.value}")
String value;
#Bean
public Object test1()
{
System.out.println("test.value=" + value );
List<String> list = new ArrayList<String>();
ListFactoryBean factory = new ListFactoryBean();
factory.setSourceList(list);
return factory;
}
public static void main(String[] args)
{
SpringApplication.run(TestClass.class, args);
}
}
When run with
java -Dtest.value=HELLO -jar myTest.jar
It loads in the value correctly:
test.value=HELLO
However, when I specify that the bean to be loaded is in fact a factory bean, and run it in the same way:
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.beans.factory.config.AbstractFactoryBean;
import org.springframework.beans.factory.config.ListFactoryBean;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
#EnableAutoConfiguration
public class TestClass
{
#Value("${test.value}")
String value;
#Bean
public AbstractFactoryBean test1()
{
System.out.println("test.value=" + value );
List<String> list = new ArrayList<String>();
ListFactoryBean factory = new ListFactoryBean();
factory.setSourceList(list);
return factory;
}
public static void main(String[] args)
{
SpringApplication.run(TestClass.class, args);
}
}
The value is null because it hasn't been injected yet.
test.value=null
Is there any way around this?
Thanks
Spring often has to query bean definitions for the type of object they produce. Factory beans are always problematic because they can cause dependency cascades in a futile attempt to resolve all dynamic information available before asking for the type.
I think ListFactoryBean is insufficiently precise about its product type (getObjectType() can only return a non-generic List.class). You might be able to write your own factory that is parameterized with the correct generic type. Or you might get away with just declaring the #Bean to return a FactoryBean<List<String>.
Another tip is to move the #Bean definition to a separate class (e.g. a nested static one) so that it can be instantiated independently of the rest of the application context. E.g.
#EnableAutoConfiguration
public class TestClass
{
protected static class NestedConfiguration {
#Value("${test.value}")
String value;
#Bean
public FactoryBean<Properties> test1()
{
System.out.println("test.value=" + value );
// ...
return factory;
}
}
...
}
Not really a Boot question this one so you might consider changing the tags.
Take look at Empowering your apps with Spring Boot's property support
There is new annotation #EnableConfigurationProperties in Spring Boot Actuator
The Spring Environment is a collection of name-value pairs taken from (in order of decreasing precedence)
1) the command line,
2) the external configuration file,
3) System properties,
4) the OS environment.
There is also possible to define application properties (external configuration) in YAML format.

Resources