xml互转Bean,json(dom4j,xpath,Xstream)

//使用jaxb對xml進行實體轉換，同時使用trang工具包生成實體類
@Test
public void xml(){
   List<User>  list = userService.findAll();//查詢的結果
   Document document = DocumentHelper.createDocument();  
       Element nodesElement = document.addElement("allUser");  
       int i = 0;  
       for (User o : list) {  
           Element nodeElement = nodesElement.addElement("oneUser");  
           if (o instanceof Map) {  
               for (Object obj : ((Map) o).keySet()) {  
                   Element keyElement = nodeElement.addElement("user");  
                   keyElement.addAttribute("label", String.valueOf(obj));  
                   keyElement.setText(String.valueOf(((Map) o).get(obj)));  
               }  
           } else {  
               Element keyElement = nodeElement.addElement("user");
               keyElement.addAttribute("id",o.getId()+""); 
               keyElement.addAttribute("name",o.getName()); 
               keyElement.addAttribute("password",o.getPassword()); 
               keyElement.addAttribute("gender",o.getGender()); 
               keyElement.addAttribute("age",o.getAge());
               keyElement.setText(String.valueOf(o));
           }  
           i++;  
       }  
       doc2String(document); 
       
}
//生成xml
public String doc2String(Document document) {  
       String s = "";  
       try {  
           // 使用输出流来进行转化  
           ByteArrayOutputStream out = new ByteArrayOutputStream();  
           // 使用UTF-8编码  
           OutputFormat format = new OutputFormat("   ", true, "UTF-8");  
           XMLWriter writer = new XMLWriter(out, format);  
           writer.write(document);  
           s = out.toString("UTF-8");//生成xml
           xml2java(s);//转换实体
           dom4j(s);//Xpath配合dom4j
           dom4jAndXpath(s);
       } catch (Exception ex) {  
           ex.printStackTrace();  
       }  
       return s;
   }  
//转换实体
public void xml2java(String xml){
 JAXBContext jb;
 Unmarshaller unmarshaller;
 AllUser allUser;
try {
jb = JAXBContext.newInstance(AllUser.class);
unmarshaller = jb.createUnmarshaller();
       allUser = (AllUser)unmarshaller.unmarshal(new ByteArrayInputStream(xml.getBytes()));
       String age = allUser.getOneUser().get(0).getUser().getAge();
       System.out.println(age);
} catch (JAXBException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
 * 這是xml
 * <?xml version="1.0" encoding="UTF-8"?>

      * <allUser> 

      *     <oneUser>

      *       <user age="w" gender="w" password="w" name="www" id="40">User [id=40, name=www, password=w, gender=w, age=w]</user> 

      *     </oneUser> 

      *     <oneUser> 

      *       <user age="w" gender="w" password="w" name="www" id="41">User [id=41, name=www, password=w, gender=w, age=w]</user> 

      *     </oneUser>

      *  </allUser>
 * @param xml
 */
//dom4j
public void dom4j(String xml){
Document document;
SAXReader saxReader = new SAXReader();
try {
document = saxReader.read(new ByteArrayInputStream(xml.getBytes("UTF-8")));
Element  e = document.getRootElement();//获取根节点(allUser)
List list = e.elements();//获取根节点裡面所有的节点(oneUser)
for(Iterator it = list.iterator();it.hasNext();){
Element el = (Element) it.next();
Element user = el.element("user");//(user)
String age = user.attributeValue("age");
String name = user.attributeValue("name");
String text = user.getTextTrim();
System.out.println(age+"="+name+"="+text);
}
} catch (DocumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch (UnsupportedEncodingException e1) {

}
}  
 
//Xpath配合dom4j
public void dom4jAndXpath(String xml){
 
Document document;
SAXReader saxReader = new SAXReader();
try {
document = saxReader.read(new ByteArrayInputStream(xml.getBytes("UTF-8")));
List list = document.selectNodes("//allUser/oneUser/user");//如果要某一個屬性可以使用@屬性名稱
for(Iterator it = list.iterator();it.hasNext();){
Object obj = it.next();
}
System.out.println(list.size());
} catch (DocumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch (UnsupportedEncodingException e1) {

}
 
}
 
 
//Xstream的使用,也是一種對bean轉換成xml,json
@Test
public void Xstream(){
List<User>  list = userService.findAll();//查詢的結果
XStream x = new XStream();
x.alias("User", User.class);//為生成的xml節點重命名
String xml = x.toXML(list);//生成xml
System.out.println(xml);
List<User> user = (List<User>) x.fromXML(xml);//反序列化
System.out.println(user.size());
//序列化成json
XStream xstream = new XStream(new JettisonMappedXmlDriver());

// xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("user", User.class);
String json = xstream.toXML(list);
System.out.println(json);
List<User> jsonUser = (List<User>) xstream.fromXML(json);
System.out.println(jsonUser.size());

}

总的来说stream要简单些