如何通过RESTful Web服务-JAX-RS使用JAXB更新XML元素列表？

Question

I have an XML file that generated by JAXB. what I expected to do is put "Add and Update" operation within single method. "Add" operation works to append new entry/element but failed to update the existing item properly.

If I want to change the id value of "Damien" to "P005", it will create new element with same name but different id (Damien, P005). the previous value still there (Damien, P004).

Any suggestion ? Thanks before.

here the XML file

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<getPersonsData>
   <person>
      <name>Alice</name>
      <id>P001</id>
   </person>
   <person>
      <name>Bob</name>
      <id>P002</id>
   </person>
   <person>
       <name>Charlie</name>
       <id>P003</id>
   </person>
    <person>
       <name>Damien</name>
       <id>P004</id>
    </person>

</getPersonsData>

here the JAXB class of Person

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
"name",
"id"
 })
 @XmlRootElement(name = "person")
 public class Person {

  @XmlElement(required = true)
  protected String name;
  @XmlElement(required = true)
  protected String id;

 public String getName() {
    return name;
 }


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


 public String getId() {
    return id;
 }


 public void setid(String value) {
    this.id = value;
 }

 }

here the JAXB class of GetPersonsData

  @XmlAccessorType(XmlAccessType.FIELD)
  @XmlType(name = "", propOrder = {
  "person"
  })
  @XmlRootElement(name = "getPersonsData")
  public class GetPersonsData {

@XmlElement(name="person", required = true)
    protected List<Person> person;


    public List<Person> getPersons() {
    if (person == null) {
        person = new ArrayList<Person>();
    }
    return this.person;
    }
 }

here the RESTFul Web Service (JAX-RS) class

@Path("/rest")
@Consumes({ MediaType.APPLICATION_FORM_URLENCODED, MediaType.APPLICATION_JSON })
@Produces(MediaType.APPLICATION_JSON)
public class PersonConfig{        

     /**
 * POST Method to add/update name and id
 * 
 */
@POST
@Path("/saveperson")
@Consumes({ MediaType.APPLICATION_FORM_URLENCODED,
        MediaType.APPLICATION_JSON })
@Produces(MediaType.APPLICATION_JSON)
public void savePerson(@FormParam("name") String name,
        @FormParam("id") String id) {


    try {

        String tesfile = "root/data/person.xml";
        File file = new File(tesfile);


        JAXBContext jc = JAXBContext.newInstance(GetPersonsData.class);
        Unmarshaller unmarshaller = jc.createUnmarshaller();

        // unmarshalling xml file
        GetPersonsData getPersonsData = (GetPersonsData) unmarshaller
                .unmarshal(file);

        // get list of persons
        List<Person> listPerson = getPersonsData.getPersons();
        Iterator<Person> iter = listPerson.iterator();
        Person  person  = iter.next();


                 //if person not exist, append new entry (element) to xml
                 //this code works, but I failed to update the existing 
                 //element.
                 //If I want to update the id or name that already exist  
                 //it will create new person with same name but different id and 
                 //vice versa.
             if(!person.getName().equals(name)){
                Person p = new Person();
                p.setName(name);
                p.setId(id);
                listPerson.add(p);
         }else if (!person.getId().equals(id){
                     person.setId(id);
                 }


        // Marshalling Object to the xml file
        Marshaller m = jc.createMarshaller();
        m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        m.marshal(getConfigInputType, file);
        m.marshal(getConfigInputType, System.out);

    } catch (ParserConfigurationException e) {

        e.printStackTrace();
    } catch (SAXException e) {

        e.printStackTrace();
    } catch (IOException e) {

        e.printStackTrace();
    } catch (JAXBException e) {

        e.printStackTrace();
    } catch (TransformerFactoryConfigurationError e) {

        e.printStackTrace();
    }

}

Answer 1

Issue might be that you are not looping the List . From the below source of yours, you are just taking the first item for comparison.

Person  person  = iter.next();

You need to loop the entire list for comparison.

Answer 2

@Jayamohan

I already put a loop like this: but the code only works for update only, not for "Add" element

 for (Iterator<Person> iterator = listPerson .iterator(); iterator.hasNext(); )
 {  
  Person person= iterator.next();
   //this peace of code works for update value
   if(person.getName().equals(name) && !person.getId().equals(id)){ 
    person.setId(id); 
   }else if (!person.getName().equals(name) && person.getId().equals(id)){  
     person.setName(name); 
    } 
  }