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：
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Controller
@ResponseBody
public @interface RestController {
/**
* The value may indicate a suggestion for a logical component name,
* to be turned into a Spring bean in case of an autodetected component.
* @return the suggested component name, if any
* @since 4.0.1
*/
String value() default "";
}
官方文档解释：
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。
示例：
UserDetails.java
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
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 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>
