GWT Spring Integration.

[kartik hedau]

hello i am trying to integrate GWT with spring,when ever i run the code it shows following error.

Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String com.login.client.GreetingService.login(java.lang.String,java.lang.String)' threw an unexpected exception: java.lang.NullPointerException

reetingServiceImpl.java[color=#444444] [/color]

@SuppressWarnings("serial")
@Service("GreetingService")
public class GreetingServiceImpl extends RemoteServiceServlet  implements
		GreetingService {
	
	@Autowired
	private LoginDao logindao;
	
	@Override
	public String login(String username, String password) {
		// TODO Auto-generated method stub
		Log.info("USername+++"+username);
		Log.info("Password+++"+username);
		
		
		Log.info("-------->"+logindao.DomainLogin(username, password));
		String returnstring= logindao.DomainLogin(username, password);
		
		
		//ApplicationContext context = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
		//LoginDaoImpl loginimp = (LoginDaoImpl)context.getBean("Logindao");

		//return loginimp.DomainLogin(username, password); //logindao.DomainLogin(username, password);
		return returnstring;
		}
}

LoginDao.java

@Component
public interface LoginDao {
	
	public String DomainLogin(String username,String password);
	
}

LoginDaoImpl.java

@Component("Logindao")
public class LoginDaoImpl implements LoginDao {

	@Override
	public String DomainLogin(String username, String password) {
		// TODO Auto-generated method stub
		System.out.println(username +"------"+password);
		if(username.equals("k")&&password.equals("k"))
			return "Authenticated";
		else
			return "You are not Authorized";
	}

}

web.xml
<servlet> <servlet-name>greetServlet</servlet-name> <servlet-class>com.login.server.GreetingServiceImpl</servlet-class> </servlet> <!-- for spring--> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener>

applicationContext.xml
<context:component-scan base-package="com.login"/> <bean id="GreetingServiceImpl" class="com.login.server.GreetingServiceImpl"></bean>
when ever i use following code

ApplicationContext context = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
LoginDaoImpl loginimp = (LoginDaoImpl)context.getBean("Logindao");

its working well but i want to use logindao(Autowired) instance to access the method directly to access dao.

Thank you in Advance.

[Ankit Garg]

There are two instance of GreetingServiceImpl. One instance gets the auto-wired LoginDao instance through Spring. The second instance is registered as a Servlet in your web.xml file. As a quick hack you can try to make the LoginDao property in GreetingServiceImpl static. You can also try following this tutorial or use spring4gwt...

[spec india]

Hi There,

I would suggest you go for this library

https://code.google.com/p/gwtrpc-spring/

It is very easy to use. You just need to follow couple of steps

1) Add the Library into your Project.

2) Add the below mentioned entry in web.xml

<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.gwtrpcspring.RemoteServiceDispatcher</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>*.rpc</url-pattern>
</servlet-mapping>

3) Define below in your applicationContext.xml for your RPC classes

<context:component-scan base-package=

4) Mark your Remove Service with Below mentioned Annotation

@RemoteServiceRelativePath("somegoodname.rpc")

5) Make sure that your RPC implementation is marked with below mentioned annotation. Also they should purely implement RemoteServiceInterface. Nothing else.

@Component



Let me know if this helps.

Thanks,