I have troubles getting a javax.servlet.ServletConfig into a class annotated with org.springframework.context.annotation.Configuration.
My team decided that we should use spring for dependency injection and I'm trying to use it to migrate one of our simple Rest services.
My constraints are:
JAX-RS: We have several REST Services implemented JAX-RS and we don't really want to change that.
Not bound to a specific implementation of JAX-RS (Jersey & RESTEasy work fine for us and we can change from one to the other without changing underlying code)
Import as few dependencies as possible from spring: at the moment I import only org.springframework:spring-context from the spring project.
No API breakage: Deprecated is fine but the service should keep working during the transition, using our old way of doing things.
A string parameter is defined in the service's web.xml. I need to get it, instantiate a Bean with it and inject the resulting bean at several place in the code.
I don't want to mess with Spring Boot/MVC/... as the service already works and I just want the Dependency Injection part.
What I already have:
The code use javax.ws.rs.core.Application, with a class that look like that:
public class MyApplication extends Application {
#Context
private ServletConfig cfg;
public DSApplication() {
}
#Override
public Set<Class<?>> getClasses() {
return new HashSet<>();
}
#Override
public Set<Object> getSingletons() {
Set<Object> set = new HashSet<>();
String injectionStr = cfg.getInitParameter("injection");
boolean injection = false;
if (null != injectionStr && !injectionStr.isEmpty()) {
injection = Boolean.valueOf(injectionStr);
}
if (injection) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
DSServiceProducer.class,
CContextBeanProvider.class
);
IDSService service = context.getBean(IDSService.class);
set.add(service);
} else {
set.add(new DSService()); //Old way
}
return set;
}
}
I need the servlet config in CContextBeanProvider, which look like:
#Configuration
public class CContextBeanProvider {
private ServletConfig cfg; // How to get this here ?
#Bean
public CContextBean cContextBean() {
String bean = cfg.getInitParameter("cpuContext");
return new CContextBean(bean);
}
}
CContextBean is a setting bean initialized from a string found in the web.xml of the service.
Is it possible ?
Do you have any idea how ?
Would it be easier with CDI, knowing that we run on base Tomcat ? (I've already find this if I need to use tomcat with CDI)
Could you please try to add all jersey CDI related jars to your applications ?
Related
I am trying to implement Hibernate second level caching in a Spring boot project using Redisson.
I have followed this blog as a reference
https://pavankjadda.medium.com/implement-hibernate-2nd-level-cache-with-redis-spring-boot-and-spring-data-jpa-7cdbf5632883
Also i am trying to initialize the RedissionClient programmatically and not through declaratively /through a config file
Created a spring bean to be initialized which should create the RedissonClient instance.
#Configuration
#Lazy(value = false)
public class RedissonConfig {
#Bean
public RedissonClient redissionClient() {
Config config = new Config();
config.useSingleServer().setAddress("redis://127.0.0.1:6379");
return Redisson.create(config);
}
}
However this bean is never intialized and i get the following error while application startup.
Caused by: org.hibernate.cache.CacheException: Unable to locate Redisson configuration
at org.redisson.hibernate.RedissonRegionFactory.createRedissonClient(RedissonRegionFactory.java:107) ~[redisson-hibernate-53-3.12.1.jar:3.12.1]
at org.redisson.hibernate.RedissonRegionFactory.prepareForUse(RedissonRegionFactory.java:83) ~[redisson-hibernate-53-3.12.1.jar:3.12.1]
It seems Spring boot Hibernate still trying to load the Redisson config through a config file.
is it possible to load the Redission config in spring boot programmatically ?
Best Regards,
Saurav
I just did exactly this, here is how:
you need a custom RegionFactory that is similar to the JndiRedissonRegionFactory but gets its RedissonClient injected somehow.
an instance of this Class, fully configured, is put into the hibernate-properties map. Hibernates internal code is flexible: if the value of hibernate.cache.region.factory_class is a string it is treated as a FQDN. If it is an instance of Class<?>, it will be instantiated. If it is an Object, it will be used.
Spring offers a rather simple way to customize hibernate properties with a bean:
#AutoConfiguration(after = RedissonAutoConfiguration.class, before = JpaAutoConfiguration.class)
#ConditionalOnProperty("spring.jpa.properties.hibernate.cache.use_second_level_cache")
public class HibernateCacheAutoConfiguration {
#Bean
public HibernatePropertiesCustomizer setRegionFactory(RedissonClient redisson) {
return hibernateProperties -> hibernateProperties.put(AvailableSettings.CACHE_REGION_FACTORY, new SpringBootRedissonRegionFactory(redisson));
}
}
My RegionFactory is really simple:
#AllArgsConstructor
public class SpringBootRedissonRegionFactory extends RedissonRegionFactory {
private RedissonClient redissonClient;
#Override
protected RedissonClient createRedissonClient(Map properties) {
return redissonClient;
}
#Override
protected void releaseFromUse() {
}
}
I used the redisson-starter to get a RedissonClient, hence the reference to RedissonAutoConfiguration, but you could just create an instance by hand.
It is possible, but then you need to provide a custom implementation of RegionFactory to Hibernate, which can extends RedissonRegionFactory but uses your own client instance.
I am trying to create a lightweight web service around a legacy java library to expose it as a web service using Spring Boot. I am new to Spring, while I have a lot of java experiance writing libraries all my web service experiance is in ASP.NET.
I can instantiate an instance of my library object but I can't figure out how to then have that object be injected into my controllers via #Autowired when the application is spun up.
This is my main application:
#SpringBootApplication
public class ResolverWebServiceApplication {
private static ArgumentParser newArgumentParser() {
ArgumentParser parser = ArgumentParsers.newFor("Resolver").build();
// configuring the parser
return parser;
}
public static void main(String[] args) throws ArgumentParserException {
ArgumentParser parser = newArgumentParser();
Namespace ns = parser.parseArgs(args);
ResolverOptions options = new ResolverOptions.Builder(ns)
.build();
ResolverContext context = new ResolverContext(options);
// ^^^ I need to get this injected into my controllers ^^^
SpringApplication.run(ResolverWebServiceApplication.class, args);
}
}
And then a simple controller which needs the class injected:
#RestController
public class VersionController {
#Autowired
private ResolverContext context; // And here the instance needs to be injected.
#GetMapping(path = "/version", produces = MediaType.APPLICATION_JSON_VALUE)
public long version() {
return context.getResolver().getVersionAsLong();
}
}
I could make the context a singleton which the controllers just refer to but I want to be able to test my controllers by mocking the context. There is also obviously a lot of validation and error handeling that needs to be added.
I can't have it be a Bean since I only want to instantiate one for my entire application.
The closest question I have found is this one: Registering an instance as 'singleton' bean at application startup. But I can't put the options in the configuration files. The application might be spun up in a container or on a users machine and requires the ability to accept arguments to initialize the library class. It would be a real usability degradation if someone had to manually edit the application config for these options.
You need to tell spring to consider the required classes from your lib when initializing the application context i.e Configure and let spring know how to create a bean and then let spring handle dependency injection for you.
First of all, add required jar that you have in your build file, say pom.xml for maven, in your current project. Idea is to have it on your classpath when you build the project.
As you said it is legacy lib and I am assuming it is not a spring bean, then
In your configuration class, return it as a bean, using #Bean annotaion.
#Configuration
public class YourConfigurationClass {
#Bean
SomeBean returnSomeBeanFromLegacyLib() {
return new SomeClassFromLib();
}
Once you return this bean from your config, it should be available to Spring Context for dependency injection whereever you #Autowire the required dependency.
This question already has answers here:
Injecting beans into a class outside the Spring managed context
(8 answers)
Closed 3 years ago.
Introduction
I have some business logic properties in the application.yml file.
They are loaded into the application via a #ConfigurationProperties annotated class.
How could I use these properties in a class which is not a Spring Bean? It cannot be a singleton, because many objects of it must be created during run-time.
Example
application.yml
business.foo: 2
BusinessProperties.java
#ConfigurationProperties("business")
#Getter // lombok
#Setter // lombok
public class BusinessProperties {
private int foo;
}
TypicalBean.java
#Component
public class TypicalBean {
private final BusinessProperties properties;
#Autowired
public TypicalBean(BusinessProperties properties) {
this.properties = properties;
}
#PostConstruct
public void printFoo() {
System.out.println("Foo: " + properties.getFoo()); // "Foo: 2"
}
}
NonBean.java
public class NonBean {
public void printFoo() {
System.out.println("Foo: ???"); // How to access the property?
}
}
Is there some way to create a non-singleton class, which can have access to configuration (or even other Spring beans) but otherwise works the same as a regular java class? Meaning that I can control its creation, it is collected by the garbage collector if not used anymore, etc.
You can still define the NonBean.class as a Component with Scope.Prototype
#Component
#Scope(value = BeanDefinition.SCOPE_PROTOTYPE)
public class NonBean {
#Autowired
public TypicalBean(BusinessProperties properties) {
this.properties = properties;
}
public void printFoo() {
System.out.println("Foo: " + properties.getFoo());
}
}
The trick is how you create an instance of NonBean.class. In the code where you'll be creating an instance of NonBean.class, use Spring's ObjectFactory<T>
private final ObjectFactory<NonBean> nonBeanFactory;
...
NonBean nonBean = nonBeanFactory.getObject();
The instantiated nonBean object will have been autowired.
All spring-beans creates by SpringApplicationContext. Bean - it's simple POJO-object, but created by Spring and saved in his container. If you want to get access to bean from outside of container - see this:
Getting Spring Application Context
Spring beans are really meant to be used within the application context but you might be able to achieve what you want by autowiring the properties to a static field in a Spring bean.
#Component
public class BusinessPropertiesUtils {
public static BusinessProperties INSTANCE;
#Autowired
public setBusinessProperties(BusinessProperties properties) {
this.INSTANCE = properties;
}
}
And then:
public class NonBean {
public void printFoo() {
System.out.println("Foo: " + BusinessPropertiesUtils.INSTANCE.getFoo());
}
}
PS: this is very hacky and definitely not the "Spring way".
You can configure beans with the prototype scope, which will give you a new instance of the bean every time it's requested.
From the Spring documentation:
In contrast to the other scopes, Spring does not manage the complete lifecycle of a prototype bean. The container instantiates, configures, and otherwise assembles a prototype object and hands it to the client, with no further record of that prototype instance.
...
In some respects, the Spring container’s role in regard to a prototype-scoped bean is a replacement for the Java new operator. All lifecycle management past that point must be handled by the client.
Example of how you can convert the TypicalBean class to a prototype scoped bean:
#Component
#Scope("prototype")
public class TypicalBean {
...
}
Another alternative is to manually instantiate the bean class (or any POJO) and injecting the dependencies (configuration, spring beans, etc.) through the constructor or setter methods, if you have them available or can get them from the Spring Context.
new TypicalBean(properties);
I'm using Jersey 2 and Spring, and I'm trying to initialize my Jersey application (i.e. the class derived from ResourceConfig) with parameters from the Spring context.
Background: I have a single Jersey application that I build (i.e. a single WAR) and I deploy it across a server cluster with different Spring configurations on different servers to enable or disable different parts of the server, e.g. some of the servers have /search resources turned on, etc. This was really easy in Jersey 1.0: I just put,
<context:component-scan base-package="com.mycompany.resources.search"/>
in a Spring config to have Jersey scan that particular package and enable the JAX-RS resource providers in it.
Now in Jersey 2.0 the Spring <context:component-scan ... /> doesn't work, so resources have to be programmatically registered in a startup class derived from ResourceConfig:
public class MyApplication extends ResourceConfig {
public MyApplication() {
packages("com.mycompany.resources.search");
}
}
So far so good, but I need to conditionally scan that package, and I can't figure out how to get any Spring configuration into the MyApplication class. I thought that constructor injection might work:
public class MyApplication extends ResourceConfig {
#Autowired
public MyApplication(#Qualifier("my-config") MyConfiguration myConfiguration) {
if (myConfiguration.isEnabled()) {
packages("com.mycompany.resources.search");
}
}
}
However HK2 complains that it can't find a default constructor to use... so this indicates to me that DI is in play in the construction of this class, but that the DI isn't using Spring.
Similarly, using the the Spring bean lifecycle doesn't work:
public class MyApplication extends ResourceConfig implements InitializingBean {
#Autowired
private MyConfiguration myConfiguration;
public MyApplication() {
}
#Override
public void afterPropertiesSet() throws Exception {
if (myConfiguration.isEnabled()) {
packages("com.mycompany.resources.search");
}
}
}
(The afterPropertiesSet method isn't called.)
So now I'm stuck: is there any way to configure a Jersey ResourceConfig application object using Spring?
UPDATE:
I accepted #JohnR's answer below but I'll also include my eventual solution which I think is a bit cleaner. #JohnR's answer was to have the object initialized twice: first by Spring and then by Jersey/HK2. When Spring initializes the object you cache the dependencies in a static member, and then when Jersey/HK2 initializes it later you can retrieve the dependencies.
I ended up doing this:
public class MyApplication extends ResourceConfig {
public MyApplication() {
ApplicationContext rootCtx = ContextLoader.getCurrentWebApplicationContext();
MyConfiguration myConfiguration = rootCtx.getBean(MyConfiguration.class);
if (myConfiguration.isEnabled()) {
packages("com.mycompany.resources.whatever");
}
}
}
Rather than having the object initialized twice, we let Jersey/HK2 initialize it but then we retrieve the dependencies from Spring.
Both solutions are vulnerable to timing: they both assume that Spring is initialized before Jersey/HK2.
Expanding on my previous comment:
Trying to extend ResourceConfig is dangerous if you don't know what you're doing. Jersey becomes unpredictable, and if you try to subclass it into an Abstract class, Jersey crashes.
Instead, the JAX-RS specification provides us with a very useful interface called Feature: It allows you to register any classes you want as if you were configuring your own application. Furthermore, you don't need to use the awkward AbstractBinder, you just specify what contracts you register your classes with.
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import javax.ws.rs.container.DynamicFeature;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.ContainerResponseFilter;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
// Don't use #Component here, we need to inject the Spring context manually.
public class MySpringFeature implements Feature {
#Context
private ServletContext servletContext;
private ApplicationContext applicationContext;
#Autowired
private MySecurityDAO mySecurityDAO;
#Autowired
private MySpringResponseFilter myResponseFilter;
#Override
public boolean configure(FeatureContext context) {
if(this.servletContext == null) {
return false; // ERROR!
}
this.applicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
if(this.applicationContext == null) {
return false; // ERROR!
}
// This is where the magic happens!
AutowireCapableBeanFactory bf = applicationContext.getAutowireCapableBeanFactory();
bf.autowireBean(this);
// From here you can get all the beans you need
// Now we take a Spring bean instance,
// and register it with its appropriate JAX-RS contract
context.register(myResponseFilter, ContainerResponseFilter.class);
// Or, we could do this instead:
SomeSecurityFilter mySecurityFilter = new SomeSecurityFilter();
mySecurityFilter.setSecurityDAO(mySecurityDAO);
context.register(mySegurityFilter, ContainerRequestFilter.class);
// Or even this:
SomeOtherSpringBean someOtherBean = applicationContext.getBean(SomeOtherSpringBean.class);
context.register(someOtherBean, SomeOtherJerseyContract.class);
// Success!
return true;
}
}
And in your ResourceConfig:
public class MyApplication extends ResourceConfig() {
public MyApplication() {
register(MySpringFeature.class);
}
}
Ta-da!
So now I'm stuck: is there any way to configure a Jersey
ResourceConfig application object using Spring?
I don't think you can configure Jersey to obtain your ResourceConfig from Spring as a Spring managed bean. It's a bit hackish, but you could do something like this. Note that you'll end up with two instance of your ResourceConfig: one managed by Spring and another by Jersey:
public class MyApplication extends ResourceConfig {
// static, available to all instances
private static MyConfiguration myConfiguration;
public MyApplication() {
// when Spring creates the first instance of MyApplication, myConfiguration
// will be null because the setter wasn't called yet
if (myConfiguration != null)
{
// second instance created by jersey... Spring will have autowired
// the first instance, and myConfiguration is static
if (myConfiguration.isEnabled())
packages("com.mycompany.resources.search");
}
}
#Autowired
public void setMyConfiguration(MyConfiguration config)
{
// instance level setter saves to a static variable to make it available for
// future instances (i.e. the one created by jersey)
MyApplication.myConfiguration = config;
}
}
Again, this is fairly hackish. You'll want to make sure Spring is initialized before Jersey and look closely at any threading issues that could occur during initialization.
I’m considering to replace the DefaultSessionAttributeStore implementation of Spring MVC 3.2.5 with some class of my own, and I’ve known from the source code that in my 3.2.5 spring source, it’s SessionAttributesHandler which possesses a SessionAttributeStore interface reference and invokes the session store function. My question is how to replace that by DI? The SessionAttributesHandler holds a final private sessionAttributeStore reference and can only be set by the constructor:
public class SessionAttributesHandler {
...
private final SessionAttributeStore sessionAttributeStore;
...
public SessionAttributesHandler(Class<?> handlerType, SessionAttributeStore sessionAttributeStore) {
Assert.notNull(sessionAttributeStore, "SessionAttributeStore may not be null.");
this.sessionAttributeStore = sessionAttributeStore;
SessionAttributes annotation = AnnotationUtils.findAnnotation(handlerType, SessionAttributes.class);
if (annotation != null) {
this.attributeNames.addAll(Arrays.asList(annotation.value()));
this.attributeTypes.addAll(Arrays.<Class<?>>asList(annotation.types()));
}
for (String attributeName : this.attributeNames) {
this.knownAttributeNames.put(attributeName, Boolean.TRUE);
}
}
...
}
Are all the components of spring mvc managed in the spring DI container? How to inject my own SessionAttributeStore implementation into SessionAttributesHandler? What does the "Class handlerType" argument mean in the constructor? From source, it seems like it's the "controller" class. Since SessionAttributesHandler is invoked and held by a ModelFactory, and in ModelFactory there is no code instantiating the SessionAttributesHandler, is there any "XML" bean configuration file for the Spring MVC inner components and how to overwrite them?
If you want to provide your own implementation of a SessionAttributeStore you need to manually configure the RequestMappingHandlerAdapter and set your custom implementation on there. That will take care of using it through-out the rest of the infrastructure.
Assuming that you use java config you can do the following
#Configuration
public class MyConfiguration extend WebMvcConfigurationSupport {
#Bean
public SessionAttributeStore sessionAttributeStore() {
return new MyCustomSessionAttributeStore();
}
#Override
#Bean
public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
RequestMappingHandlerAdapter rmha = super.requestMappingHandlerAdapter();
rmha.setSessionAttributeStore(sessionAttributeStore());
return rmha;
}
}
If you want to do this in XML you either have to write a BeanPostProcessor which sets it on the default RequestMappingHandlerAdapter instance created by <mvc:annotation-driven /> or configure it manually and drop the namespace support.