How to initialized java bean with annotation in spring framework? - spring

Question

I have a Java bean:
public class User{
private Integer userid;
private String username;
private String password;
private boolean enable;
//getter and setter
}
I am able to initialize it as a spring bean at context.xml via:
<context:component-scan base-package="com.myCompany.myProject" />
But I don't want initialize it in xml. How can I initialize it with sring 3 annotation. I tried with the following:
#Component
public class User{
private Integer userid;
private String username;
private String password;
private boolean enable;
//getter and setter
}
But the above did not work for me. Any ideas?

Answer 1

I believe that is because you have enable component scan on the package com.myCompany.myProject and not on the package com.myCompany.myProject.db
Change your scan definition to this : <context:component-scan base-package="com.myCompany.myProject.db" /> (or add a new one, if you want classes from the other package as well) and you can remove the bean definition from XML and have your annotation work for you.
Silly, but still, ensure that the #Component annotation is that of Spring's. I've at times faced this silly issue of defining an annotation that is actually not from the desired library (owing to the same name of the annotation, by different libraries in my classpath).

Answer 2

You need to add
<context:annotation-config />
With this XML my Autowiring works flawless:
<?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:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
<context:annotation-config />
<context:component-scan base-package="com.vanilla.example"></context:component-scan>
</beans>

Answer 3

you shouldn't need to have both declared.
Use of context:annotation-config allows for autowiring of beans via annotations etc
Use of context:component-scan provides everything that context:annotation-config, but allows for autodiscovery of beans. The package you supply in context:component-scan will scan that package plus all sub packages.
Hope this helps

Answer 4

Be sure that the "User" class is the package or sub-package of the
"com.myCompany.myProject".
You do NOT need to include <context: annotation-config/>, it is
included with component-scan.
The bean is available with the name "user" by default, unless you
specify the bean name with #Component("myBeanName")
Once that is done, you can autowire the bean into another with:
#Autowired
User user;
OR
#Inject
User user;
NOTES:
#Inject is a javax.inject annotation the injection is NOT required.
#Autowired is a Spring annotation and the injection is required.
#Autowired can be used in one of the following ways:
just above the member variable
constructor that accepts a User bean
setter that accepts a User bean.

Answer 5

I have configured my xml file in this way , this will help you to solve the problem.
For Context-componentscan use
<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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="com.java.Controllers"></context:component-scan>
<context:component-scan base-package="com.java.dao"></context:component-scan>
<context:component-scan base-package="com.java.bean"></context:component-scan>
Or else u can use
<context:component-scan base-package="com.java.*"></context:component-scan>
next for annotation driven use
<mvc:annotation-driven />
For resources use this
<mvc:resources location="/" mapping="/**"/>