I'm planning to create my objects in my Spring MVC using the below setup but How can I inject values to my MyService ie; instantiate the object with default value...
public class MyController {
private MyService myService;
#Autowired
public void setMyService(MyService aService) { // autowired by Spring
this.myService = aService;
}
#RequestMapping("/blah")
public String someAction()
{
// do something here
myService.foo();
return "someView";
}
}
MyService
class Myservice(){
String servicename;
public Myservice(servicename){
this.servicename = servicename;
}
}
Without Spring
MyService first = new MyService("firstservice");
MyService second = new MyService("secondservice");
Just declare your constructor with #Autowired to mark it as the constructor to use and its parameter with #Value to indicate the value to use.
#Autowired
public Myservice(#Value("example") String servicename){
Or use a placeholder
#Autowired
public Myservice(#Value("${placeholder.key}") String servicename){
Firstly, your exam are wrong on using Spring DI. To inject Myservice type to another You should declare MyService as a interface instead:
interface Myservice(){
public void foo();
}
After that, declare an implementation of this interface (again, use Spring DI to inject String type):
class BarService() implements Myservice{
String servicename;
#Autowired
public Myservice(#Value("servicename") String servicename){
this.servicename = servicename;
}
public void foo(){
}
}
Related
I have the following immutable class (i.e. in separate library I can't change):
public class MyClass implements InitializingBean, BeanNameAware {
private BeanA prop1;
private BeanB prop2;
public MyClass() {}
#Override
public void afterPropertiesSet() {
// do smth with prop1 and prop2
}
}
I need to create multiple different MyClass beans but with property values (prop1, prop2) that are generated in runtime.
How to implement that?
I tried to implement FactoryBean<MyClass>, but the method FactoryBean#getObject doesn't have parameters.
BeanFactory#getBean with arguments can't be used, because MyClass doesn't have constructor arguments for those properties (it's separate library).
you could use javax.annotation.#PostContruct
#Component
public class MyClass {
private BeanA prop1;
private BeanB prop2;
#PostConstruct
public void doSomethingAfterInstanced() {
prop1 = null;
prop2 = new BeanB();
}
}
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I have an abstract class with some configuration properties value which are set using #Value. I want to reuse the abstract class but with another set of configuration properties. The issue is that, those properties value have already been set in the abstract class and all of the concrete classes have inherited it.
I have thought about:
creating another set of config values in the abstract class, but that seems to be creating duplicate, but this is not quite extensible when in future there is yet a third set of config values.
changing the accessibly of the config value in the abstract class from private to protected and have the concrete class to override it. But I'm not sure this kind of overriding is good as it seems create confusion as to what is the actual config value.
create another abstract class which is similar as "AbstractService" but injecting the different set of config value using #Value. This also seems to create duplication.
public abstract class AbstractService {
#Value("${config1}")
private String config1;
#Value("${config2}")
private String config2;
public void serviceMethod() {
//using config1 and config 2 values
}
}
public class concreteServiceA extends AbstractService {
public void serviceA() {
// using serviceMethod in the abstract class
}
}
public class concreteServiceB extends AbstractService {
public void serviceB() {
// using serviceMethod in the abstract class
}
}
Would it be a good way if using constructor to pass the required parameters in the abstract class, and let the concrete classes to use constructor injection and #Value to set those values ? though if there are long list of config values this may not scale well.
public abstract class AbstractService {
private String config1;
private String config2;
public AbstractService(String config1, String config2) {
this.config1 = config1;
this.config2 = config2;
}
public void serviceMethod() {
//using config1 and config2 values
}
}
public concreteServiceA extends AbstractService {
public concreteServiceA(#Value("${config1}") String config1,
#Value("${config2}") String config2) {
super(config1, config2);
}
public void serviceA() {
//using serviceMethod in the abstract class
}
}
public concreteServiceB extends AbstractService {
public concreteServiceB(#Value("${configB1}") String config1,
#Value("${configB2}") String config2) {
super(config1, config2);
}
public void serviceB() {
//using serviceMethod in the abstract class
}
}
You can go like following:
public abstract class AbstractService {
public void serviceMethod() {
String config1 = getConfig1();
String config2 = getConfig2();
//using config1 and config 2 values
}
public abstract String getConfig1();
public abstract String getConfig2();
}
public class concreteServiceA extends AbstractService {
#Value("${config1}") private String config1;
#Value("${config2}") private String config2;
public String getConfig1(){
return config1;
}
public String getConfig2(){
return config2;
}
public void serviceA() { // using serviceMethod in the abstract class }
}
public class concreteServiceB extends AbstractService {
#Value("${config1.1}") private String config1;
#Value("${config2.1}") private String config2;
public String getConfig1(){
return config1;
}
public String getConfig2(){
return config2;
}
public void serviceB() { // using serviceMethod in the abstract class }
}
You could either use setter injection or (probably more elegant) constructor injection like this:
public abstract class AbstractService {
protected AbstractService(String config1, String config2) {
this.config1 = config1;
this.config2 = config2;
}
private String config1;
private String config2;
public void serviceMethod() {
//using config1 and config 2 values
}
}
public class ConcreteServiceA extends AbstractService {
public ConcreteServiceA(#Value("${config1a}") String config1, #Value("${config2a}") String config2) {
super(config1, config2);
}
public void serviceA() {
// using serviceMethod in the abstract class
}
}
public class ConcreteServiceB extends AbstractService {
public ConcreteServiceB(#Value("${config1b}") String config1, #Value("${config2b}") String config2) {
super(config1, config2);
}
public void serviceB() {
// using serviceMethod in the abstract class
}
}
But if you have lots of values you can also use setter injection and override the setters in each subclass. Or you can still use constructor injection but pass a container class holding the config like this:
public class ServiceConfig {
private String config1;
private String config2;
// getters, setters and more properties
}
Then pass it like this
public abstract class AbstractService {
private ServiceConfig config;
protected AbstractService(ServiceConfig config) {
this.config = config;
}
}
public class ConcreteServiceA extends AbstractService {
public ConcreteServiceA(#Value("${configA}") ServiceConfig config) {
super(config);
}
}
You can externalize your properties to specific beans which will be autowired to the concrete classes.
Spring annotation #ConfigurationProperties allows you to initialise simple POJO properties based on properties prefix.
First create your POJO which we will inject in the concrete services :
public class ServiceProperties {
private String config1;
private String config2;
//getters and setters
}
Then create a configuration class in a package scanned by spring :
#Configuration
public class ServicePropertiesConfiguration {
#Bean
#ConfigurationProperties(prefix = "service-a")
public ServiceProperties serviceAProperties() {
return new ServiceProperties();
}
#Bean
#ConfigurationProperties(prefix = "service-b")
public ServiceProperties serviceBProperties() {
return new ServiceProperties();
}
}
As you can see, prefix tells to spring where he has to search the properties. Your application.properties will look like this :
service-a.config1=serviceAConfig1
service-a.config2=serviceAConfig2
service-b.config1=serviceBConfig1
service-b.config2=serviceBConfig2
At this stage, you will have two beans of type ServiceProperties with specific values inside
The abstract service looks like this :
public abstract class AbstractService {
private final ServiceProperties serviceProperties;
protected AbstractService(ServiceProperties serviceProperties) {
this.serviceProperties = serviceProperties;
}
public void serviceMethod() {
//using config1 and config 2 values
// serviceProperties.getConfig1();
// serviceProperties.getConfig2();
}
}
In the concrete service, you have to use #Qualifier annotation with name of created bean
#Service
public class ConcreteServiceA extends AbstractService{
public ConcreteServiceA(#Qualifier("serviceAProperties") ServiceProperties serviceProperties) {
super(serviceProperties);
}
}
#Service
public class ConcreteServiceB extends AbstractService{
protected ConcreteServiceB(#Qualifier("serviceBProperties") ServiceProperties serviceProperties) {
super(serviceProperties);
}
}
I have a POJO class:
#Data #Document
public class RoomPreferences{
private TypeEnum roomType;
private BigDecimal minLen;
private BigDecimal maxLen;
private List<BigDecimal> defaultPrices;
}
I want to populate a RoomPreferences object at test and I am using Mockito, but my RoomPreferences object's fields are always null.
public class TestingClass {
#Mock private RoomPreferences roomPreferences;
#InjectMocks public RoomServiceImpl roomService;
#Before
public void init() {
MockitoAnnotations.initMocks(this);
}
#Test
public void test() {
when(roomPreferences.getMinLen()).thenReturn(BigDecimal.valueOf(10));
...
}
}
What I read out of this testing class:
public class TestingClass {
#Mock private RoomPreferences roomPreferences;
#InjectMocks public RoomServiceImpl roomService;
#Before
public void init() {
MockitoAnnotations.initMocks(this);
}
#Test
public void test() {
when(roomPreferences.getMinLen()).thenReturn(BigDecimal.valueOf(10));
...
}
}
is that roomService of type RoomServiceImpl has an attribute of type RoomPreferences. And this attribute will be injected with the mocked object "roomPreferences".
The mocked object won't be populated with any value of the real class.
What you do is define what the mock should do when a method (as in the real class) is called on it:
when(roomPreferences.getMinLen()).thenReturn(BigDecimal.valueOf(10));
If you wan to assing a value to a property then don't mock the class and use the real class instead.
I am guessing that the problem you are facing is setting the RoomPreferences attribute in the roomService object. If that is the case you should add that class to the question.
Having the following classes :
public class A {
#Autowired
private Set<IClient> clients;
}
public class B implements IClient { }
public class C implements IClient { }
#RunWith(MockitoJUnitRunner.class)
public class Atest {
#InjectMocks
A a;
#Mock
IClient clients;
}
How I can use mocks for the Set of interfaces that will include both class B and C?
Use constructor injection insted of field injection, then create two mocks, put them in a set, and call your constructor with that set. For example:
public class Atest {
private A a;
#Mock
private IClient mockAClient;
#Mock
private IClient mockBClient;
#Before
public void prepare() {
a = new A(new HashSet<>(Arrays.asList(mockAClient, mockBClient));
}
}
Spring (from version 4) claims to support generic type injection and I'm trying to do something like this:
public abstract class AbstractControl<T extends IService> {
#Autowired
private T service;
protected T getService(){
return service;
}
public void setService(T service) {
this.service = service;
}
}
then an extension of this class:
public class FooControl extends AbstractControl<LoginService> {
}
but Spring is trying to inject IService. Is it possible to inject the inherited type?
Try moving the #Autowired into the subclass, like this:
public abstract class AbstractControl<T extends IService> {
private T service;
protected T getService(){
return service;
}
public void setService(T service) {
this.service = service;
}
}
And the subclass:
public class FooControl extends AbstractControl<LoginService> {
#Override
#Autowired
public void setService(LoginService service) {
this.service = service;
}
}