我使用Spring Boot 1.2.5创建了一个简单的REST Web服务，它对于JSON可以正常工作，但是我无法使它返回XML。

这是我的控制器：

@RestController
..
@RequestMapping(method = RequestMethod.GET,  produces = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE})
@ResponseStatus(HttpStatus.OK)
public List<Activity> getAllActivities() {
    return activityRepository.findAllActivities();
}

当我调用它时Accept: application/json一切正常，但是当我尝试时application/xml我得到一些带有406错误和消息的HTML：

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

我的模型对象：

@XmlRootElement
public class Activity {

    private Long id;
    private String description;
    private int duration;
    private User user; 
    //getters & setters...
}

@XmlRootElement
public class User {

    private String name;
    private String id;
    //getters&setters...
}

我的pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.2.5.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>

</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

我需要在pom.xml中添加一些其他jar来使其工作吗？我尝试添加jaxb-api或jax-impl，但没有帮助。