public class JAXBUtils {
    public static String convertToXml(Object obj, boolean format) throws Exception {
        try {
            StringWriter sw = new StringWriter();
            Marshaller marshaller = MarshallerFactory.getMarshaller(obj.getClass());
            if (marshaller == null) {
                return StringUtils.EMPTY;
            }

            marshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, format);
            marshaller.marshal(obj, sw);
            return sw.toString();
        } catch (JAXBException e) {
            throw new RuntimeException("obj toXML failed", e);
        }
    }

    public static <T> T convertToJavaBean(String xml, Class<T> t) throws Exception {
        try {
            Unmarshaller unmarshaller = MarshallerFactory.getUnmarshaller(t);
            if (unmarshaller == null) {
                return null;
            }

            StringReader sr = new StringReader(xml);
            T ret = null;
            ret = (T) unmarshaller.unmarshal(sr);
            return ret;
        } catch (JAXBException e) {
            throw new RuntimeException("xml toObj failed", e);
        }
    }
}
 

public class MarshallerFactory {

    private final static HashMap<Class, JAXBContext> JAXB_CONTEXT_MAP = Maps.newHashMap();

    private MarshallerFactory() {
    }

    static {
        try {
            JAXB_CONTEXT_MAP.put(RequestBean.class, JAXBContext.newInstance(RequestBean.class));
            // 想要進行的bean轉換的類，可以寫在這裡，初始化到Map中
        } catch (Exception e) {
            // 列印日誌
        }
    }

    public static Marshaller getMarshaller(Class t) throws JAXBException {
        Preconditions.checkNotNull(t);
        JAXBContext jaxbContext = JAXB_CONTEXT_MAP.get(t);
        if(jaxbContext == null) {
            return null;
        }

        return jaxbContext.createMarshaller();
    }

    public  static Unmarshaller getUnmarshaller(Class t) throws JAXBException {
        Preconditions.checkNotNull(t);
        JAXBContext jaxbContext = JAXB_CONTEXT_MAP.get(t);
        if(jaxbContext == null) {
            return null;
        }

        return jaxbContext.createUnmarshaller();
    }
}
 

主要就是三個介面，Marshaller、UnMarchaller和JAXBContext

• JAXBContext類，是應用的入口，通過該類建立序列化和反序列化物件，也即編組物件和解組物件；
• Marshaller 編組介面，將Java物件序列化為XML資料；
• Unmarshaller 解組介面，將XML資料反序列化為Java物件。

為了便於支援多個bean的轉換，可以將需要轉換的類都放進Factory的靜態Map中，需要用的時候直接拿出來就行了。

至於如何寫bean，一種方法是手寫，建議參考這篇部落格https://www.cnblogs.com/chenbenbuyi/p/8283657.html

主要是弄懂各個標籤的含義和作用。

另外一種方法是通過xsd檔案（相當於xml的格式模板），使用IDEA的JAXB工具反向生成Java bean