spring4.0重要的一個新的改進是@RestController注解，它繼承自@Controller注解。4.0之前的版本，Spring MVC的組件都使用@Controller來標識當前類是一個控制器servlet。

使用這個特性，我們可以開發(fā)REST服務(wù)的時候不需要使用@Controller而專門的@RestController。

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當你實現(xiàn)一個RESTful web services的時候，response將一直通過response body發(fā)送。為了簡化開發(fā)，Spring 4.0提供了一個專門版本的controller。下面我們來看看@RestController實現(xiàn)的定義：

@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 "";}

官方文檔解釋：

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。使用了這個注解的類會被看作一個controller-使用@RequestMapping的方法有一個默認的@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也可以加到類一級，通過繼承方法一級不需要添加。

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

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<?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>

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轉(zhuǎn)載于:https://www.cnblogs.com/duanxz/p/7491161.html

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