Mapping XML Entities to Java Objects

Question

I am quite sure, this is one of the many duplicated questions around XML to Java Object conversions. But I started this thread since I couldn't find simpler or looking for simpler solution.

I have an xsd [Infact I am designing it] and xml. I would like to auto-map the xml data to Java beans as per mapping

<tns:SummaryCart xmlns:tns="SummaryCart" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="SummaryCart.xsd">     <SummaryElement type="test">         <order>1</order>         <id>A</id>         <displayName>A</displayName>         <subElements>             <order>1</order>             <id>Preactivation</id>             <displayName>Preactivation</displayName>         </subElements>         <maxlines>1</maxlines>     </SummaryElement> </tns:SummaryCart> 

Now my Java classes will be

public class SummaryCart{     private List<SummaryElement> summaryElementList; } public class SummaryElement {     private int order;     private String id;     private String displayName;     private String property;     private List<SummaryElement> subElements;     private int maxlines;     private String type; } 

Is there any simple tool/framework which can auto-map the data from XML to Java beans [MUST support attributes/element mapping]. Tutorial will be good.

Btw, I am using Spring framework, if spring-oxm advantage is taken, its welcome.

Answer 1

Below is how you could map your object to XML using JAXB (JSR-222). An implementation is included in the JDK/JRE starting with Java SE 6. JAXB is supported by Spring (see section 8.5: http://static.springsource.org/spring-ws/site/reference/html/oxm.html)

SummaryCart

import java.util.List; import javax.xml.bind.annotation.*;  @XmlRootElement(name="SummaryCart", namespace="SummaryCart") @XmlAccessorType(XmlAccessType.FIELD) public class SummaryCart{      @XmlElement(name="SummaryElement")     private List<SummaryElement> summaryElementList;  } 

SummaryElement

import java.util.List; import javax.xml.bind.annotation.*;  @XmlAccessorType(XmlAccessType.FIELD) public class SummaryElement {      private int order;     private String id;     private String displayName;     private String property;     private List<SummaryElement> subElements;     private int maxlines;      @XmlAttribute     private String type;  } 

Demo

import java.io.File; import javax.xml.bind.*;  public class Demo {      public static void main(String[] args) throws Exception {         JAXBContext jc = JAXBContext.newInstance(SummaryCart.class);          Unmarshaller unmarshaller = jc.createUnmarshaller();         File xml = new File("src/forum15881876/input.xml");         SummaryCart sc = (SummaryCart) unmarshaller.unmarshal(xml);          Marshaller marshaller = jc.createMarshaller();         marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);         marshaller.setProperty(Marshaller.JAXB_SCHEMA_LOCATION, "SummaryCart.xsd");         marshaller.marshal(sc, System.out);     }  } 

input.xml/Output

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <ns2:SummaryCart xmlns:ns2="SummaryCart" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="SummaryCart.xsd">     <SummaryElement type="test">         <order>1</order>         <id>A</id>         <displayName>A</displayName>         <subElements>             <order>1</order>             <id>Preactivation</id>             <displayName>Preactivation</displayName>             <maxlines>0</maxlines>         </subElements>         <maxlines>1</maxlines>     </SummaryElement> </ns2:SummaryCart> 

Answer 2

Basically you want to unmarshal your XML. Here's a detailed tutorial that describes how to use the JAXB xjc command to generate a Java class from XML Schema. A maven xjc plugin is also available for your convenience.