JAXB and property ordering

Question

I want the serialized XML output from my Java class to honor the ordering of the properties in the Java class.

It seems that JAXB orders alphabetically.

I can override this by using @XmlType with propOrder and specifying ALL of the properties, but I have a class with many properties and these are not yet finalized.

I read that specifying an empty propOrder would do it but it don't.

My example class:

package test;  import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlRootElement; import javax.xml.bind.annotation.XmlType;  @XmlRootElement //@XmlType(propOrder={"company", "scheme", "agreementNumber"}) @XmlType(propOrder={}) // makes no difference - still alphabetical in XML  public class CustomerPlan2 {      private String company;     private String scheme;     private String agreementNumber;      @XmlElement(name="Company")     public String getCompany() {         return company;     }     public void setCompany(String company) {         this.company = company;     }      @XmlElement(name="Scheme")     public String getScheme() {         return scheme;     }     public void setScheme(String scheme) {         this.scheme = scheme;     }      @XmlElement(name="AgreementNumber")     public String getAgreementNumber() {         return agreementNumber;     }     public void setAgreementNumber(String agreementNumber) {         this.agreementNumber = agreementNumber;     } } 

My serialize code:

    CustomerPlan2 cp2 = new CustomerPlan2();      cp2.setCompany("company");     cp2.setScheme("scheme");     cp2.setAgreementNumber("agreementnumber");     JAXBContext context = JAXBContext.newInstance(CustomerPlan2.class);     Marshaller marshaller = context.createMarshaller();      marshaller.marshal(cp2, new FileWriter("C:\\temp\\out.xml")); 

Output:

    <customerPlan2>       <AgreementNumber>agreementnumber</AgreementNumber>        <Company>company</Company>        <Scheme>scheme</Scheme>      </customerPlan2> 

I want my output to be (as the property order of my class):

    <customerPlan2>       <Company>company</Company>       <Scheme>scheme</Scheme>        <AgreementNumber>agreementnumber</AgreementNumber>      </customerPlan2> 

Thanks for any help on this.

Answer 1

It's possible using:

@XmlType (propOrder={"prop1","prop2",..."propN"}) 

Just uncomment the code like this:

//@XmlType(propOrder={"company", "scheme", "agreementNumber"}) 

This is the correct usage.

Answer 2

Note: I lead EclipseLink JAXB (MOXy)

The order in which Java reflection returns the list of fields/properties is not guaranteed. This is why JAXB implementations do not use it to determine element order.

By default JAXB provides no guaranteed ordering. However most (if not all JAXB implementations) use alphabetical ordering since it is deterministic. To guarantee this ordering you must annotate your class as follows:

@XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL) public class Foo {     ... }