I have just learnt Spring Framework and have been using Spring 2.5 for this learning. I have created three beans with these classes
Food.java
package com.spring.danipetrick;
public interface Food {
void ingredients();
}
NasiGoreng.java
package com.spring.danipetrick;
public class NasiGoreng implements Food {
public NasiGoreng() {
}
public void ingredients() {
System.out.println("Rice, Coconut oil, Egg, Crackers");
}
#Override
public String toString() {
return "Nasi Goreng";
}
}
Rendang.java
package com.spring.danipetrick;
public class Rendang implements Food {
public void ingredients() {
System.out.println("Beef, Coconut milk, spices");
}
#Override
public String toString() {
return "Rendang";
}
}
PecintaKuliner.java
package com.spring.danipetrick;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
public class PecintaKuliner {
#Autowired
#Qualifier("nasigoreng")
private Food food;
#Autowired
public void setFood(Food food) {
this.food = food;
}
public Food getFood() {
return this.food;
}
public void sayMaknyus() {
System.out.println(food.toString() + " memang maknyus...");
}
}
Xml configuration, qualifier-test.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<context:annotation-config />
<bean id="bondan" class="com.spring.danipetrick.PecintaKuliner">
</bean>
<bean id="rendang" class="com.spring.danipetrick.Rendang"/>
<bean id="nasigoreng" class="com.spring.danipetrick.NasiGoreng" />
</beans>
Finally, class with main method is QualifierTestMain.java:
package com.spring.danipetrick;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class QualifierTestMain {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("/qualifier-test.xml");
PencintaKuliner bondan = (PencintaKuliner)context.getBean("bondan");
bondan.sayMaknyus();
}
}
When I run this project, I have an error like this
Caused by:
org.springframework.beans.factory.NoSuchBeanDefinitionException: No
unique bean of type [com.spring.danipetrick.Food] is defined: expected
single matching bean but found 2: [rendang, nasigoreng]
Why #Qualifier annotation is not working in my case?
Both your method and field are annotated with #Autowired. As such, Spring will try to inject both. On one of the runs, it will try to inject
#Autowired
#Qualifier("nasigoreng")
private Food food;
which will work because the injection target is qualified.
The method however
#Autowired
public void setFood(Food food) {
this.food = food;
}
does not qualify the injection parameter so Spring doesn't know which bean to inject.
Change the above to
#Autowired
public void setFood(#Qualifier("nasigoreng") Food food) {
this.food = food;
}
But you should decide one or the other, field or setter injection, otherwise it is redundant and may cause errors.
I tried with Spring 4.2.4. Problem resolved just by adding
<context:annotation-config /> in configuration file.
Try only removing #Autowired from setFood() in PecintaKuliner
like
#Autowired
#Qualifier("nasigoreng")
private Food food;
public void setFood(Food food) {
this.food = food;
}
Try removing you constructor from the NasiGoreng class. It worked for me.
For others facing issue in Spring 5 -- Use xmlns based configuration..
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:annotation-config/>
</beans>
Related
I have tennisCoach object created by Spring framework:
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml") ;
Coach theCoach = context.getBean("tennisCoach", Coach.class);
Can't understand why I need #Autowired annotation in TennisCoach constructor in code below. It works fine with and without #Autowired annotation.
#Component
public class TennisCoach implements Coach {
private FortuneService fortuneService;
#Autowired
public TennisCoach(FortuneService theFortuneService) {
fortuneService = theFortuneService;
}
#Override
public String getDailyWorkout() {
return "Practice your backhand volley";
}
#Override
public String getDailyFortune() {
return fortuneService.getFortune();
}
}
UPD
Content of applicationContext.xml :
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="com.luv2code.springdemo"></context:component-scan>
</beans>
From #Autowired Javadoc:
If a class only declares a single constructor to begin with, it will always be used, even if not annotated.
Since Spring 4.3 you don’t need the #Autowired annotation as soon as you have the only constructor in your class.
Here #Autowired is used for constructor injection. TennisCoach has a dependency on FortuneService and it is injected through constructor. I'm not sure how you have configured beans in applicationContext.xml
package com.mkyong.output;
IOutputGenerator.java
public interface IOutputGenerator
{
public void generateOutput();
}
package com.mkyong.output;
OutputHelper.java
#Component
public class OutputHelper {
#Autowired
IOutputGenerator outputGenerator;
public void generateOutput() {
outputGenerator.generateOutput();
}
/*//DI via setter method
public void setOutputGenerator(IOutputGenerator outputGenerator) {
this.outputGenerator = outputGenerator;
}*/
}
package com.mkyong.output.impl;
CsvOutputGenerator.java
#Component
public class CsvOutputGenerator implements IOutputGenerator {
public void generateOutput() {
System.out.println("This is Csv Output Generator");
}
}
SpringBeans.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<context:component-scan base-package="com.mkyong" />
</beans>
i am getting this exception Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'OutputHelper' is defined
even though i have marked OutputHelper as component.
I have changed
OutputHelper output = (OutputHelper) context.getBean("OutputHelper");
to
OutputHelper output = (OutputHelper) context.getBean("outputHelper");
and it worked.
Hi i think you haven't added following in your Spring XML configuration
xmlns:mvc="http://www.springframework.org/schema/mvc"
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
<mvc:annotation-driven/>
you need to see top exception and read the whole line.
i guess there have a exception is nested exception just like #Autowired xxxxxx,meas autowired fail.
i have notice this:
#Autowired
IOutputGenerator outputGenerator;
and
#Component
public class CsvOutputGenerator implements IOutputGenerator
so, in the default, class name is used to #Autowired，you can rewrite to
#Autowired
IOutputGenerator csvOutputGenerator;
notice:
"csvOutputGenerator" first letter is lowercase
the easier option would be to enable annotations in beans already registered in the application context, means that you can just use #Autowired instead of getting manually all beans with context.getBean()
just add this line to your SpringBeans.xml
<context:annotation-config>
if you really want to understand what you are doing reading this could help.
I have 2 classes in 2 different projects, and I have some difficulties to autowire a field.
In project pack, I have this Computation class :
package fr.aaa;
#Component
public class Computation {
#Autowired
#Qualifier("curveDAO")
CurveAccess curveDAO;
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("classpath*:applicationContext.xml");
}
}
In project db, I have this CurveAccess interface :
package com.bbb
public interface CurveAccess {
// some methods
}
implemented by a CurveDAO class :
package com.bbb.impl
#Repository("curveDAO")
#Transactional("cvaTxManager")
public class CurveDAO implements CurveAccess {
// some methods
}
My applicationContext.xml file from pack project :
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"
xmlns:security="http://www.springframework.org/schema/security" xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.3.xsd">
<import resource="classpath:spring/persistence.xml"/>
<context:annotation-config />
<context:component-scan base-package="fr.aaa.*, com.bbb.*"/>
<util:properties id="jdbcProps" location="jdbc.properties" />
<bean id="propertyConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:configuration.properties</value>
<value>classpath:jdbc.properties</value>
</list>
</property>
</bean>
When running, I have this exception :
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'Computation': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.bbb.CurveAccess fr.aaa.Computation.curveDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.bbb.CurveAccess] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true), #org.springframework.beans.factory.annotation.Qualifier(value=curveDAO)}
How can I solve this problem ?
Actually, your code works perfectly fine:
#SpringBootApplication
public class So21481801Application implements CommandLineRunner {
public interface CurveAccess {
String hello();
}
#Repository("curveDAO")
public class CurveDAO implements CurveAccess {
#Override
public String hello() {
return "Hello";
}
}
#Repository("curveDAOWorld")
public class CurveDAOWorld implements CurveAccess {
#Override
public String hello() {
return "World";
}
}
#Autowired
#Qualifier("curveDAO")
CurveAccess curveDAO;
#Autowired
#Qualifier("curveDAOWorld")
CurveAccess curveDAOWorld;
#Override
public void run(String... args) {
System.out.println(curveDAO.hello());
System.out.println(curveDAOWorld.hello());
}
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(So21481801Application.class, args);
context.close();
}
}
Probably you have some problem on how you are using the component-scan configuration on XML and the Java annotations. Mix them is not a good idea.
You need a class that implements CurveAccess interface
#Component
public class CurveAccessImpl implements CurveAccess {
//methods
}
Also remove Qualifier from curveDao in Computation bean since there is no such bean with id curveDao.
#Autowired
CurveAccess curveDAO;
Could someone help me why it is not working,
CustomerService
package com.aop.sample;
public interface CustomerService {
void addCustomer();
String addCustomerReturnValue();
void addCustomerThrowException() throws Exception;
void addCustomerAround(String name);
}
CustomerServiceImpl
package com.aop.sample;
import org.springframework.stereotype.Component;
#Component
public class CustomerServiceImpl implements CustomerService{
public void addCustomer(){
System.out.println("addCustomer() is running ");
}
public String addCustomerReturnValue(){
System.out.println("addCustomerReturnValue() is running ");
return "abc";
}
public void addCustomerThrowException() throws Exception {
System.out.println("addCustomerThrowException() is running ");
throw new Exception("Generic Error");
}
public void addCustomerAround(String name){
System.out.println("addCustomerAround() is running, args : " + name);
}
}
LoggingAspect
package com.aop.sample;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
#Aspect
public class LoggingAspect {
#Before("execution(* com.aop.sample.CustomerService.addCustomer(..))")
public void logBefore(JoinPoint joinPoint) {
System.out.println("logBefore() is running!");
System.out.println("hijacked : " + joinPoint.getSignature().getName());
System.out.println("******");
}
}
TestRun
package com.aop.sample;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestRun {
public static void main(String[] args) {
final ClassPathXmlApplicationContext appContext = new ClassPathXmlApplicationContext(
"/META-INF/spring/app-context.xml");
CustomerService customerService = (CustomerService) appContext.getBean("customerServiceImpl");
customerService.addCustomer();
}
}
app-context.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<description>Example configuration to get you started.</description>
<aop:aspectj-autoproxy proxy-target-class="true"/>
<context:component-scan base-package="com.aop.sample" />
</beans>
-My Current output is -
addCustomer() is running
-Expected Out put-
logBefore() is running!
hijacked : addCustomer
******
addCustomer() is running
Kindly advice, What I'm doing wrong
Annotate your LoggingAspect class with #Component so a bean can be generated
#Aspect
#Component
public class LoggingAspect {
and registered. Alternatively, add a <bean> element in the context file for LoggingAspect.
Add this to the app-context.xml if you dont want to use annotations.
<bean name="loggingAspect" class="com.aop.sample.LogginAspect"/>
http://docs.spring.io/spring/docs/3.1.0.M1/spring-framework-reference/html/aop.html#aop-at-aspectj
We have an application where we are trying to inject an empty java.util.HashSet into a member of type java.util.Set, in a class which itself is a #Component. Spring seems to inject a HashSet with one element of the containing type. Any idea why Spring doesn't just inject an empty set?
Set element class:
#Component
public class SetElement
{
private String value;
public String getValue()
{
return value;
}
}
Class that contains a Set as a member:
#Component
public class MyClassWithSet
{
#Autowired
private Set<SetElement> setOfElements;
protected void setStringSet(Set<SetElement> stringSet)
{
this.setOfElements = stringSet;
}
public Set<SetElement> getStringSet()
{
return Collections.unmodifiableSet(setOfElements);
}
}
Spring.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
">
<bean id="setOfElements" class="java.util.HashSet" />
<context:component-scan base-package="com.vikdor.db " />
</beans>
Sample test case to confirm the behavior
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations =
{ "classpath:META-INF/spring.xml" })
public class SpringSetTest
{
#Autowired
private MyClassWithSet myClassWithSet;
#Test
public void test()
{
assertNotNull(myClassWithSet);
assertNotNull(myClassWithSet.getStringSet());
assertTrue(myClassWithSet.getStringSet().isEmpty());
}
}
If you use #Autowired on a typed collection instance, then all beans in the application context that satisfy the type are injected:
It is also possible to provide all beans of a particular type from the
ApplicationContext by adding the annotation to a field or method that
expects an array of that type [...] The same applies for typed
collections:
public class MovieRecommender {
private Set<MovieCatalog> movieCatalogs;
#Autowired
public void setMovieCatalogs(Set<MovieCatalog> movieCatalogs) {
this.movieCatalogs = movieCatalogs;
}
// ...
}
http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/html/beans.html#beans-autowired-annotation
Thus, your single instance of SetElement is injected into the #Autowired Set<SetElement>. A possible solution would be to use a setter for the field. Alternatively, you could use the #Qualifier annotation or the #Resource annotation to refer to the bean by name.