java - @RestController 抛出 HTTP 状态 406

Question

我正在使用 Spring 和 Restful web 服务开发一个基本的 Hello World 程序。但是当我尝试调用我的服务时，我收到以下错误消息:

HTTP Status 406 -

description - The resource identified by this request is only capable of generating responses with characteristics not acceptable according to the request "accept" headers.

这是我的 web.xml 文件的 servlet 映射:

<servlet>
    <servlet-name>mvc-dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>mvc-dispatcher</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

这是我的 spring web 配置文件:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc" 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.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="hello" />

    <mvc:annotation-driven />

    <!-- Map returned view name "rssViewer" to bean id "rssViewer" 
    <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" />
        -->
    <bean id="xmlViewer" 
        class="org.springframework.web.servlet.view.xml.MarshallingView">
        <constructor-arg>
            <bean class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
                <property name="classesToBeBound">
                    <list>
                        <value>hello.Greeting</value>
                    </list>
                </property>
            </bean>
        </constructor-arg>
    </bean>
</beans>

这是我的 Maven pom.xml 文件:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.examples</groupId>
    <artifactId>WebServices1</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>WebServices1 Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <properties>
        <spring.version>4.1.6.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- for compile only, your container should have this -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>


        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.13</version>
        </dependency>

    </dependencies>
    <build>
        <finalName>WebServices1</finalName>
    </build>
</project>

这是我的 Controller :

package hello;

import java.util.concurrent.atomic.AtomicLong;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class GreetingController {

    private static final String template = "Hello, %s!";
    private final AtomicLong counter = new AtomicLong();

    @RequestMapping("/greeting")
    public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) {
        return new Greeting(counter.incrementAndGet(),
                            String.format(template, name));
    }
}

这是我的 Greeting pojo 类:

package hello;

public class Greeting {

    private final long id;
    private final String content;

    public Greeting(long id, String content) {
        this.id = id;
        this.content = content;
    }

    public long getId() {
        return id;
    }

    public String getContent() {
        return content;
    }
}

当我部署我的应用程序并以 http://localhost:8081/WebServices1/rest/greeting 访问 URL 时，我在浏览器中收到 HTTP 406 错误消息.

更新:

根据我的 mozilla firebug 插件，这里是我的请求 header :

Accept  
text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding 
gzip, deflate
Accept-Language 
en-US,en;q=0.5
Cache-Control   
max-age=0
Connection  
keep-alive
Cookie  
JSESSIONID=9B49E7A23D6CDE85CAC4152E22834D35; textwrapon=false; textautoformat=false; wysiwyg=textarea
; m=34e2:|2663:t|c01:t|5cf4:t|4a01:t|54e1:t
Host    
localhost:8081
User-Agent  
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0

响应 header :

Content-Language    
en
Content-Length  
1067
Content-Type    
text/html;charset=utf-8
Date    
Mon, 22 Jun 2015 11:00:08 GMT
Server  
Apache-Coyote/1.1

Answer 1

问题在于您在 pom.xml 文件中的依赖项。

在 Spring 4.1.* 版本中，Jackson 库的 pom.xml 依赖项应该包括:

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.4.1</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.4.1.1</version>
    </dependency>

您可以在这些帖子中获得更多详细信息:

Spring JSON request getting 406 (not Acceptable) - bekur 给出的答案

还有这里:

406 Spring MVC Json, not acceptable according to the request "accept" headers

另外仅供引用，如果您将 spring 版本更改回 4.0.* 或其他任何版本，您的代码将正常工作。