Spring MVC 3.1 的RequestMapping注解里增加了produces属性， 可以明确指定返回响应的格式为特定的格式，比如XML格式。

XmlResponseController.java

@RequestMapping(value = "/only-xml-response", method = RequestMethod.GET, produces = MediaType.APPLICATION_XML_VALUE)
@ResponseBody
public Object onlyXml(ModelMap modelMap){
    //BookDTO 是增加了JAXB注解的一个JavaBean
    BookDTO b = new BookDTO("Java in Action");
    return b;
    //也可以返回字符串
    //return "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><book><name>java in action.</name></book>";
}

BookDTO的代码是这样的：

@XmlRootElement(name="book")
public class BookDTO {

    String name;


    public BookDTO() {
    }

    public BookDTO(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    @XmlElement
    public void setName(String name) {
        this.name = name;
    }

}

JAXB in JDK6
JAXB is included in JDK6, so, you do not need to include JAXB library manually, as long as object is annotated with JAXB annotation, Spring will convert it into XML format automatically.