Spring Mvc Rest
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The document discusses building RESTful applications with Spring MVC. It covers the pillars of REST including resources, URIs, HTTP methods, and representations. It provides examples of modeling resources as controllers and mapping HTTP methods to controller actions. It also discusses content negotiation, supporting different data representations like JSON, XML and RSS using Spring views.
Spring Mvc Rest
- 1. Building RESTful applications with Spring MVC Craig Walls
- 2. Who Am I? Java, Spring, and OSGi fanatic Principal Consultant with Improving Author XDoclet in Action (Manning) Spring in Action (Manning) Modular Java (Pragmatic Bookshelf) E-mail: [email protected] Blog: http://www.springinaction.com Twitter: @habuma Slides: http://www.slideshare.net/habuma
- 3. What REST is NOT!!! Web Services with URLs E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 4. It’s about Resources Things, not actions Requests, not demands Resources, not services Transfer of state, not RPC E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 5. The Pillars of REST Resources URIs/URLs HTTP Methods Representations E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 6. The Pillars of REST Resources Produced as model data in Spring MVC Controllers URIs/URLs Supported in handler methods by @PathParam HTTP Methods @RequestMapping, HiddenHttpMethodFilter, <form:form> Representations Rendered by view resolvers HTML, XML, JSON, RSS, Atom, PDF, Excel, etc. Negotiated by ContentNegotiatingViewResolver E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 7. Identifying Resources E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 8. Demanding URLs Direct Imperative Resource identifier Command is pushed into a query parameter http://www.somestore.com/displayProduct?sku=1234 Very service-y Not very cacheable or search engine friendly E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 9. Resourceful URLs The focus is on the product, We’re requesting not the action a product’s info http://www.somestore.com/product/1234 Cacheable This URL also identifies a product (within a context) E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 10. Spring MVC overview E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 11. DispatcherServlet In /WEB-INF/web.xml <servlet> <servlet-name>spitter</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spitter</servlet-name> <url-pattern>/app/*</url-pattern> </servlet-mapping> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 12. ContextLoaderListener In /WEB-INF/web.xml <context-param> <param-name>contextConfigLocation</param-name> <param-value> /WEB-INF/spitter-security.xml classpath:service-context.xml classpath:persistence-context.xml classpath:dataSource-context.xml classpath:setup-context.xml </param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 13. UrlRewriteFilter In /WEB-INF/web.xml <filter> <filter-name>UrlRewriteFilter</filter-name> <filter-class> org.tuckey.web.filters.urlrewrite.UrlRewriteFilter </filter-class> </filter> <filter-mapping> <filter-name>UrlRewriteFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> In /WEB-INF/urlrewrite.xml <urlrewrite default-match-type="wildcard"> <rule> 1234 /pr oduct/ <from>/resources/**</from> <to>/resources/$1</to> /1234 </rule> uct /ap p/prod <rule> <from>/**</from> <to>/app/$1</to> </rule> <outbound-rule> <from>/app/**</from> <to>/$1</to> </outbound-rule> </urlrewrite> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 14. Essential Configuration Scan for controller (and other) components <context:component-scan base-package="com.habuma.sample.mvc" /> Resolve JSP views <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> Handle annotation-driven request mappings <mvc:annotation-driven/> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 15. Use-case-based controllers VERB!!! @Controller public class DisplayProductController { @RequestMapping(value="/displayProduct.htm") public String showProductBySku(String sku, Map<String,Object> model) { Product product = // ... lookup product ... model.put("product", product); return "product"; } // ... } http://host/myApp/displayProduct.htm?sku=1234 E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 16. Resource-oriented controller Noun @Controller Verb @RequestMapping("/product") public class ProductController { @RequestMapping(value="/{sku}", method=GET) public String showProductBySku( @PathVariable String sku, Map<String,Object> model) { Product product = // ... lookup product ... model.put("product", product); return "product"; } } http://host/myApp/product/1234 E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 17. HTTP Methods GET, DELETE, PUT Idempotent Transfers state of resource POST Not Idempotent Sends data (not nec. state) E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 18. PUT vs. POST PUT Used to transfer state to server Useful when the resource’s URL is known POST Used to send data to server Useful when the resource’s URL is unknown or when transferring partial state E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 19. Handling DELETE @Controller @RequestMapping("/product") public class ProductController { ... @RequestMapping(value="/{sku}", method=DELETE) public String deleteProduct( @PathVariable String sku) { // ... delete product ... return "redirect:home"; } } http://host/myApp/product/1234 E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 20. Handling PUT @Controller @RequestMapping("/product") public class ProductController { ... @RequestMapping(value="/{sku}", method=PUT) public String saveProduct( @PathVariable String sku, Product product) { // ... save product ... return "redirect:/product/" + sku; } } http://host/myApp/product/1234 E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 21. Handling POST @Controller @RequestMapping("/product") public class ProductController { ... @RequestMapping(method=POST) public String setPrice(String sku, double price) { // ... update price ... return "redirect:/product/" + sku; } } http://host/myApp/product FORM DATA: sku=1234 price=5.99 E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 22. Using PUT/DELETE in forms Most browsers only support GET and POST Spring’s <form:form> supports all <form:form method="DELETE" action="http://host/myApp/product/1234"> ... </form:form> Hidden method field <form method="POST" action="http://host/myApp/product/1234"> <input type="hidden" name="_method" value="DELETE"> ... </form> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 23. HiddenHttpMethodFilter <filter> <filter-name>httpMethodFilter</filter-name> <filter-class> org.springframework.web.filter.HiddenHttpMethodFilter </filter-class> </filter> <filter-mapping> <filter-name>httpMethodFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> HiddenHttpMethodFilter POST DELETE _method=DELETE E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 24. Data representation PDF RSS/Atom Spring MVC Views JSON Excel E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 25. Negotiating Content Request Content Negotiating View Resolver E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 26. Choosing a view 1. Determine the media type URL path extension/mediaTypes format parameter URL path extension/JAF HTTP Accept header 2. Find a view resolver that serves that media type E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 27. ContentNegotiatingViewResolver <bean class="org.springframework.web.servlet.view. ContentNegotiatingViewResolver"> <property name="mediaTypes"> <map> <entry key="htm" value="text/html"/> <entry key="json" value="application/json"/> </map> </property> <property name="defaultViews"> <list> <bean class="org.springframework.web.servlet.view.json. MappingJacksonJsonView" /> </list> </property> </bean> <bean id="spittles" class="com.habuma.spitter.mvc.view.SpittlesAtomView"/> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 28. Spring’s new views MappingJacksonJsonView MarshallingView AbstractAtomFeedView AbstractRssFeedView E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 29. XML Marshalling View <bean id="oxmMarshaller" class="org.springframework.oxm.xstream.XStreamMarshaller" /> <bean id="marshallingHttpMessageConverter" class="org.springframework.http.converter.xml. MarshallingHttpMessageConverter"> <property name="marshaller" ref="oxmMarshaller" /> <property name="unmarshaller" ref="oxmMarshaller" /> </bean> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 30. Sample RSS View public class SpittlesRssView extends AbstractRssFeedView { @Override protected List<Item> buildFeedItems( Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception { @SuppressWarnings("unchecked") List<Spittle> spittles = (List<Spittle>) model.get("spittles"); List<Item> items = new ArrayList<Item>(); for (Spittle spittle : spittles) { Item item = new Item(); item.setTitle(spittle.getText()); item.setPubDate(spittle.getWhen()); item.setAuthor(spittle.getSpitter().getFullName()); items.add(item); } return items; } } E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 31. Sample Atom View public class SpittlesAtomView extends AbstractAtomFeedView { @Override protected List<Entry> buildFeedEntries( Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception { @SuppressWarnings("unchecked") List<Spittle> spittles = (List<Spittle>) model.get("spittles"); List<Entry> entries = new ArrayList<Entry>(); for (Spittle spittle : spittles) { Entry entry = new Entry(); entry.setTitle(spittle.getText()); entry.setCreated(spittle.getWhen()); entry.setAuthors(asList(spittle.getSpitter().getFullName())); entries.add(entry); } return entries; } } E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 32. ETags Returns HTTP 304 if content is unmodified if-none-match (MD5 Hash comparison) Saves bandwidth <filter> <filter-name>etagFilter</filter-name> <filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class> </filter> <filter-mapping> <filter-name>etagFilter</filter-name> <servlet-name>spitter</servlet-name> </filter-mapping> E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 33. RestTemplate In Spring context: (or yes, it could just be new’d up in Java) <bean id="restTemplate" class="org.springframework.web.client.RestTemplate"> In Java: RestTemplate rest = (RestTemplate) context.getBean("restTemplate"); Map result = rest.getForObject( "http://localhost:8080/mugbooks/book/1.json", Map.class); E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 34. Summary • Spring provides a flexible web MVC framework • Full support for REST as of Spring 3.0 • Can consume REST services via a template E-mail: [email protected] Blog: http://www.springinaction.com Twitter: habuma
- 35. Thank You Don’t forget the evals!