4.0重要的一个新的改进是@RestController注解，它继承自@Controller注解。4.0之前的版本，spring MVC的组件都使用@Controller来标识当前类是一个控制器servlet。
使用这个特性，我们可以开发REST服务的时候不需要使用@Controller而专门的@RestController。
当你实现一个RESTful web services的时候，response将一直通过response body发送。为了简化开发，Spring 4.0提供了一个专门版本的controller。下面我们来看看@RestController实现的定义：
Java代码
- @Target(value=TYPE)
- @Retention(value=RUNTIME)
- @Documented
- @Controller
- @ResponseBody
- public @interface RestController
官方文档解释：
Java代码
- A convenience annotation that is itself annotated with @Controller and @ResponseBody. Types that carry this annotation are treated as controllers where @RequestMapping methods assume @ResponseBody semantics by default.
- 注解本身使用@Controller和@ResponseBody注解。使用了这个注解的类会被看作一个controller-使用@RequestMapping的方法有一个默认的@ResponseBody注解。
- @ResponseBody – As of version 4.0 this annotation can also be added on the type level in which case is inherited and does not need to be added on the method level.
- @ResponseBody也可以加到类一级，通过继承方法一级不需要添加。
UserDetails.java
Java代码
- package javabeat.net.rest;
- import javax.xml.bind.annotation.XmlAttribute;
- import javax.xml.bind.annotation.XmlRootElement;
- @XmlRootElement
- public class UserDetails {
- private String userName;
- private String emailId;
- @XmlAttribute
- public String getUserName() {
- return userName;
- }
- public void setUserName(String userName) {
- this.userName = userName;
- }
- @XmlAttribute
- public String getEmailId() {
- return emailId;
- }
- public void setEmailId(String emailId) {
- this.emailId = emailId;
- }
- }
SpringRestControllerDemo.java
Java代码
- package javabeat.net.rest;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.http.HttpStatus;
- import org.springframework.web.bind.annotation.RequestMapping;
- import org.springframework.web.bind.annotation.RequestMethod;
- import org.springframework.web.bind.annotation.ResponseStatus;
- import org.springframework.web.bind.annotation.RestController;
- @RestController
- public class SpringRestControllerDemo {
- @Autowired UserDetails userDetails;
- @RequestMapping(value="/springcontent",
- method=RequestMethod.GET,produces={"application/xml", "application/json"})
- @ResponseStatus(HttpStatus.OK)
- public UserDetails getUser() {
- UserDetails userDetails = new UserDetails();
- userDetails.setUserName("Krishna");
- userDetails.setEmailId("krishna@gmail.com");
- return userDetails;
- }
- @RequestMapping(value="/springcontent.htm", method=RequestMethod.GET)
- @ResponseStatus(HttpStatus.OK)
- public String getUserHtml() {
- //Test HTML view
- return "example";
- }
- }
dispatcher-servlet.xml
Xml代码
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:mvc="http://www.springframework.org/schema/mvc"
- xmlns:context="http://www.springframework.org/schema/context"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
- http://www.springframework.org/schema/mvc
- http://www.springframework.org/schema/mvc/spring-mvc.xsd
- http://www.springframework.org/schema/context
- http://www.springframework.org/schema/context/spring-context-4.0.xsd">
- <context:component-scan base-package="com.infosys.rest" />
- <bean id="userDetails" class="javabeat.net.rest.UserDetails"/>
- <mvc:annotation-driven content-negotiation-manager="contentManager"/>
- <bean id="contentManager"
- class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
- <property name="favorPathExtension" value="true"/>
- <property name="ignoreAcceptHeader" value="true" />
- <property name="defaultContentType" value="text/html" />
- <property name="useJaf" value="false"/>
- <property name="mediaTypes">
- <map>
- <entry key="json" value="application/json" />
- <entry key="html" value="text/html" />
- <entry key="xml" value="application/xml" />
- </map>
- </property>
- </bean>
- <bean id="jspViewResolver"
- class="org.springframework.web.servlet.view.InternalResourceViewResolver">
- <property name="prefix" value="/WEB-INF/jsp/" />
- <property name="suffix" value=".jsp" />
- </bean>
- </beans>
