spring, multi client, Android, REST, mobile, RIA, html5,

1. Multi Client Development with Spring
Josh Long
Spring Developer Advocate
SpringSource, a Division of VMware
http://www.joshlong.com || @starbuxman || josh.long@springsource.com
© 2009 VMware Inc. All rights reserved

2. About
 SpringSource is the organization that develops the Spring
framework, the leading enterprise Java framework
 SpringSource was acquired by VMware in 2009
 VMware and SpringSource bring you to the cloud and
deliver on the mission of “build, run, manage”
• established partnerships with the major players in the business, including
Adobe, SalesForce, and Google to help deliver the best experience for
Spring users across multiple platforms
 Leading contributor to projects like
Apache HTTPD and Apache Tomcat
2

3. About Josh Long
Spring Developer Advocate
twitter: @starbuxman
josh.long@springsource.com
3

4. About Josh Long
Spring Developer Advocate
twitter: @starbuxman
josh.long@springsource.com
Contributor To:
•Spring Integration
•Spring Batch
•Spring Hadoop
•Activiti Workflow Engine
•Akka Actor engine
4

5. multi client development with Spring
Spring Primer
5

6. The Spring ApplicationContext
 Spring Beans are Managed by An ApplicationContext
• whether you’re in an application server, a web server, in regular Java SE application, in
the cloud, Spring is initialized through an ApplicationContext
• In a Java SE application:
ApplicationContext ctx =
new GenericAnnotationApplicationContext( “com.foo.bar.my.package”);
• In a web application, you will configure an application context in your web.xml
<servlet>
<servlet-name>Spring Dispatcher Servlet</servlet-name>
<servlet-
class>org.springframework.web.servlet.DispatcherServlet</servlet-
class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/myAppContext*.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
6

7. I want Database Access ... with Hibernate 4 Support
@Service
public class CustomerService {
public Customer createCustomer(String firstName,
String lastName,
Date signupDate) {
...
}
}
CONFIDENTIAL
7

8. I want Database Access ... with Hibernate 4 Support
@Service
public class CustomerService {
@Inject
private SessionFactory sessionFactory;
public Customer createCustomer(String firstName,
String lastName,
Date signupDate) {
Customer customer = new Customer();
customer.setFirstName(firstName);
customer.setLastName(lastName);
customer.setSignupDate(signupDate);
sessionFactory.getCurrentSession().save(customer);
return customer;
}
}
CONFIDENTIAL
8

9. I want Database Access ... with Hibernate 4 Support
@Service
public class CustomerService {
@Inject
private SessionFactory sessionFactory;
@Transactional
public Customer createCustomer(String firstName,
String lastName,
Date signupDate) {
Customer customer = new Customer();
customer.setFirstName(firstName);
customer.setLastName(lastName);
customer.setSignupDate(signupDate);
sessionFactory.getCurrentSession().save(customer);
return customer;
}
}
CONFIDENTIAL
9

10. I want Declarative Cache Management...
@Service
public class CustomerService {
@Inject
private SessionFactory sessionFactory;
@Transactional
@Cacheable(“customers”)
public Customer createCustomer(String firstName,
String lastName,
Date signupDate) {
Customer customer = new Customer();
customer.setFirstName(firstName);
customer.setLastName(lastName);
customer.setSignupDate(signupDate);
sessionFactory.getCurrentSession().save(customer);
return customer;
}
}
CONFIDENTIAL
10

11. I want a RESTful Endpoint...
package org.springsource.examples.spring31.web;
..
@Controller
public class CustomerController {
@Inject
private CustomerService customerService;
@RequestMapping(value = "/customer/{id}",
produces = MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody Customer customerById(@PathVariable("id") Integer id) {
return customerService.getCustomerById(id);
}
...
}
CONFIDENTIAL
11

12. DEMO
• the 80% case!
Not confidential. Tell everyone.

13. multi client development with Spring
Spring Web Support
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14. Setting up Spring on the Web is Easy
<servlet>
<servlet-name>Spring Dispatcher Servlet</servlet-name>
<servlet-
class>org.springframework.web.servlet.DispatcherServlet</servlet-
class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/myAppContext*.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
14

15. New in 3.1: XML-free web applications
 In a servlet 3 container, you can also use Java configuration,
negating the need for web.xml:
public class SampleWebApplicationInitializer implements WebApplicationInitializer {
public void onStartup(ServletContext sc) throws ServletException {
AnnotationConfigWebApplicationContext ac =
new AnnotationConfigWebApplicationContext();
ac.setServletContext(sc);
ac.scan( “a.package.full.of.services”, “a.package.full.of.controllers” );
sc.addServlet("spring", new DispatcherServlet(webContext));
}
}
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16. Thin, Thick, Web, Mobile and Rich Clients: Web Core
 Spring Dispatcher Servlet
• Objects don’t have to be web-specific.
• Spring web supports lower-level web machinery: ‘
• HttpRequestHandler (supports remoting: Caucho, Resin, JAX RPC)
• DelegatingFilterProxy.
• HandlerInterceptor wraps requests to HttpRequestHandlers
• ServletWrappingController lets you force requests to a servlet through the Spring Handler chain
• OncePerRequestFilter ensures that an action only occurs once, no matter how many filters are
applied. Provides a nice way to avoid duplicate filters
• Spring provides access to the Spring application context using
WebApplicationContextUtils, which has a static method to look up the context, even in
environments where Spring isn’t managing the web components

17. Thin, Thick, Web, Mobile and Rich Clients: Web Core
 Spring provides the easiest way to integrate with your web
framework of choice
• Spring Faces for JSF 1 and 2
• Struts support for Struts 1
• Tapestry, Struts 2, Stripes, Wicket, Vaadin, Play framework, etc.
• GWT, Flex

18. Thin, Thick, Web, Mobile and Rich Clients: Spring MVC
18

19. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
}
19

20. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”)
public String processTheRequest() {
// ...
return “home”;
}
}
GET http://127.0.0.1:8080/url/of/my/resource
20

21. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public String processTheRequest() {
// ...
return “home”;
}
}
GET http://127.0.0.1:8080/url/of/my/resource
21

22. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public String processTheRequest( HttpServletRequest request) {
String contextPath = request.getContextPath();
// ...
return “home”;
}
}
GET http://127.0.0.1:8080/url/of/my/resource
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23. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public String processTheRequest( @RequestParam(“search”) String searchQuery ) {
// ...
return “home”;
}
}
GET http://127.0.0.1:8080/url/of/my/resource?search=Spring
23

24. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/{id}”,
method = RequestMethod.GET)
public String processTheRequest( @PathVariable(“id”) Long id) {
// ...
return “home”;
}
}
GET http://127.0.0.1:8080/url/of/my/2322
24

25. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/{id}” )
public String processTheRequest( @PathVariable(“id”) Long customerId,
Model model ) {
model.addAttribute(“customer”, service.getCustomerById( customerId ) );
return “home”;
}
@Autowired CustomerService service;
}
GET http://127.0.0.1:8080/url/of/my/232
25

26. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public String processTheRequest( HttpServletRequest request, Model model) {
return “home”;
}
}
26

27. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public View processTheRequest( HttpServletRequest request, Model model) {
return new XsltView(...);
}
}
27

28. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public InputStream processTheRequest( HttpServletRequest request, Model model) {
return new FileInputStream( ...) ;
}
}
28

29. DEMO
 Demos
• Simple Spring MVC based Application
Not confidential. Tell everyone.

30. multi client development with Spring
the new hotness
30

31. dumb terminals ruled the earth....
31

32. then something magical happened: the web
32

33. but the web didn’t know how to do UI state... so we hacked...
33

34. ....then the web stopped sucking
34

35. multi client development with Spring
REST
35

36. Thin, Thick, Web, Mobile and Rich Clients: REST
 Origin
• The term Representational State Transfer was introduced and defined in 2000 by Roy
Fielding in his doctoral dissertation.
 His paper suggests these four design principles:
• Use HTTP methods explicitly.
• POST, GET, PUT, DELETE
• CRUD operations can be mapped to these existing methods
• Be stateless.
• State dependencies limit or restrict scalability
• Expose directory structure-like URIs.
• URI’s should be easily understood
• Transfer XML, JavaScript Object Notation (JSON), or both.
• Use XML or JSON to represent data objects or attributes
CONFIDENTIAL
36

37. REST on the Server
 Spring MVC is basis for REST support
• Spring’s server side REST support is based on the standard controller model
 JavaScript and HTML5 can consume JSON-data payloads

38. REST on the Client
 RestTemplate
• provides dead simple, idiomatic RESTful services consumption
• can use Spring OXM, too.
• Spring Integration and Spring Social both build on the RestTemplate where possible.
 Spring supports numerous converters out of the box
• JAXB
• JSON (Jackson)

39. Building clients for your RESTful services: RestTemplate
 Google search example
RestTemplate restTemplate = new RestTemplate();
String url = "https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q={query}";
String result = restTemplate.getForObject(url, String.class, "SpringSource");
 Multiple parameters
RestTemplate restTemplate = new RestTemplate();
String url = "http://example.com/hotels/{hotel}/bookings/{booking}";
String result = restTemplate.getForObject(url, String.class, "42", “21”);
CONFIDENTIAL
39

40. Thin, Thick, Web, Mobile and Rich Clients: RestTemplate
 RestTemplate class is the heart the client-side story
• Entry points for the six main HTTP methods
• DELETE - delete(...)
• GET - getForObject(...)
• HEAD - headForHeaders(...)
• OPTIONS - optionsForAllow(...)
• POST - postForLocation(...)
• PUT - put(...)
• any HTTP operation - exchange(...) and execute(...)
CONFIDENTIAL
40

41. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/resource”,
method = RequestMethod.GET)
public @ResponseBody Customer processTheRequest( ... ) {
Customer c = service.getCustomerById( id) ;
return c;
}
@Autowired CustomerService service;
}
41

42. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/someurl”,
method = RequestMethod.POST)
public String processTheRequest( @RequestBody Customer postedCustomerObject) {
// ...
return “home”;
}
}
POST http://127.0.0.1:8080/url/of/my/someurl
42

43. The Anatomy of a Spring MVC @Controller
Spring MVC configuration - config
@Controller
public class CustomerController {
@RequestMapping(value=”/url/of/my/{id}”,
method = RequestMethod.POST)
public String processTheRequest( @PathVariable(“id”) Long customerId,
@RequestBody Customer postedCustomerObject) {
// ...
return “home”;
}
}
POST http://127.0.0.1:8080/url/of/my/someurl
43

44. DEMO
 Demos:
• Spring REST service
• Spring REST client
Not confidential. Tell everyone.

45. DEMO
 Demos:
• Using REST from Ajax
Not confidential. Tell everyone.

46. multi client development with Spring
Spring Mobile
46

47. Thin, Thick, Web, Mobile and Rich Clients: Mobile
 Best strategy? Develop Native
• Fallback to client-optimized web applications
 Spring MVC 3.1 mobile client-specific content negotiation and
rendering
• for other devices
• (there are other devices besides Android??)
47

48. DEMO
 Demos:
• Mobile clients using client specific rendering
Not confidential. Tell everyone.

49. multi client development with Spring
Spring Android
49

50. Thin, Thick, Web, Mobile and Rich Clients: Mobile
 Spring REST is ideal for mobile devices
 Spring MVC 3.1 mobile client-specific content
negotiation and rendering
• for other devices
 Spring Android
• RestTemplate
50

51. OK, so.....
51

52. Thin, Thick, Web, Mobile and Rich Clients: Mobile
CustomerServiceClient - client
! private <T> T extractResponse( ResponseEntity<T> response) {
! ! if (response != null && response().value() == 200) {
! ! ! return response.getBody();
! ! }
! ! throw new RuntimeException("couldn't extract response.");
! }
! @Override
! public Customer updateCustomer(long id, String fn, String ln) {
! ! String urlForPath = urlForPath("customer/{customerId}");!!
! ! return extractResponse(this.restTemplate.postForEntity(
urlForPath, new Customer(id, fn, ln), Customer.class, id));
! }
52

53. Thin, Thick, Web, Mobile and Rich Clients: Mobile
 Demos:
• consuming the Spring REST service from Android

54. One Other approach
 HTML5 all the way!
• HTML5 on the desktop browser interface
• HTML5 + PhoneGap on the client
• RESTful services on the server side to connect it all

55. springsource.org | cloudfoundry.org
Questions?
Say hi!
@starbuxman | josh.long@springsource.com