Can't use #Autowired in desktop application - spring

Question

i am trying to use spring in desktop application, but i am facing a problem with autowiring in action methods of my JPanel.
i am loading the applicationContext in my main method as follows:
public static void main(String[] args) {
new ClassPathXmlApplicationContext(
"classpath:/META-INF/spring/applicationContext.xml");
MainFrame frame = new MainFrame();
Signup signup = new Signup();
frame.add(signup);
frame.setResizable(false);
frame.setTitle("Please input your data");
frame.setBounds(100, 100, 450, 180);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
and i can see that it's loaded with no problems.
my panel code:
#Component
public class Signup extends JPanel {
#Autowired
private UserDao userDao;
public Signup() {
JButton btn_submit = new JButton("Submit");
btn_submit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
registerUser();
}
});
}
private void registerUser() {
User newUser = new User();
newUser.setName(username);
newUser.setSalary(salary);
userDao.addUser(newUser);
}
}
the context:component-scan is configured properly, and i am using context:annotation-config too but i always gets NullPointerException in userDao.addUser(newUser);
which means that the Dependency Injection is not working as it should.
please advise how to fix this issue.
UPDATE: 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"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="${project.groupId}" />
<context:annotation-config />
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="propertyPlaceholderConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:messages/application.properties</value>
</list>
</property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="${project.groupId}.domain" />
<property name="hibernateProperties">
<value>
hibernate.dialect=org.hibernate.dialect.DerbyDialect
hibernate.show_sql=false
hibernate.format_sql=false
hibernate.hbm2ddl.auto=validate
</value>
</property>
</bean>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.apache.derby.jdbc.EmbeddedDriver" />
<property name="url" value="jdbc:derby:test" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="transactionManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" />
</beans>

Answer 1

If you are going to configure Spring in a desktop environment, then you must be the one to work with the ApplicationContext.
For example, if you want to get a hold of your Signup class that you have posted here, you would do something like this in your main method:
public static void main(String[] args) {
ApplicationContext appContext = new ClassPathXmlApplicationContext(
"classpath:/META-INF/spring/applicationContext.xml");
Signup signup = appContext.getBean(Signup.class);
//use signup here...
}
Using new Signup() to get a new instance of the Signup class, which won't work the way you want, because you want it to be a Spring managed class! (Actually, you could get it to work that way, but that is beyond my answer here)