将 xml 转换为 java bean

Question

How can I covert a an xml file to a simple java bean? Its a simple xml file without any xsd, which was generated from a java bean, which I don't have access to.

I tried using xmlbeans to first generate the xmd from xml and then to generate classes from the xsd. I got a bunch of classes. I am looking for a single java bean class.

Answer 1

JAXB

JAXB ( JSR-222 ) provides an easy way to convert objects to XML. There are many open source implementations of this standard including:

• Metro JAXB (the reference implementation included in Java SE 6)
• EclipseLink JAXB (MOXy) , I'm the tech lead
• Apache JaxMe

JAXB has a default mapping for Java objects to XML. This mapping can be customized through the application of annotations.

import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.Element;

@XmlRootElement
public class Address {

    private String street;

    private String city;

    private String state;

    private String country;

    @XmlElement(name="postal-code")
    private String postalCode;

}

Would correspond to the following XML:

<address>
    <street>123 A Street</street>
    <city>Any Town</city>
    <state>A State</state>
    <postal-code>12345</postal-code>
</address>

EclipseLink JAXB (MOXy)

MOXy has an XPath based mapping extension. This means we can take our same Address class and map it to Google's geocode format:

import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement(name="kml")
@XmlType(propOrder={"country", "state", "city", "street", "postalCode"})
public class Address {

    @XmlPath("Response/Placemark/ns:AddressDetails/ns:Country/ns:AdministrativeArea/ns:SubAdministrativeArea/ns:Locality/ns:Thoroughfare/ns:ThoroughfareName/text()")
    private String street;

    @XmlPath("Response/Placemark/ns:AddressDetails/ns:Country/ns:AdministrativeArea/ns:SubAdministrativeArea/ns:Locality/ns:LocalityName/text()")
    private String city;

    @XmlPath("Response/Placemark/ns:AddressDetails/ns:Country/ns:AdministrativeArea/ns:AdministrativeAreaName/text()")
    private String state;

    @XmlPath("Response/Placemark/ns:AddressDetails/ns:Country/ns:CountryNameCode/text()")
    private String country;

    @XmlPath("Response/Placemark/ns:AddressDetails/ns:Country/ns:AdministrativeArea/ns:SubAdministrativeArea/ns:Locality/ns:PostalCode/ns:PostalCodeNumber/text()")
    private String postalCode;

}

The above class corresponds to the following XML:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0" xmlns:ns="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0">
    <Response>
        <Placemark>
            <ns:AddressDetails>
                <ns:Country>
                    <ns:CountryNameCode>US</ns:CountryNameCode>
                    <ns:AdministrativeArea>
                        <ns:AdministrativeAreaName>CA</ns:AdministrativeAreaName>
                        <ns:SubAdministrativeArea>
                            <ns:Locality>
                                <ns:LocalityName>Mountain View</ns:LocalityName>
                                <ns:Thoroughfare>
                                    <ns:ThoroughfareName>1600 Amphitheatre Pkwy</ns:ThoroughfareName>
                                </ns:Thoroughfare>
                                <ns:PostalCode>
                                    <ns:PostalCodeNumber>94043</ns:PostalCodeNumber>
                                </ns:PostalCode>
                            </ns:Locality>
                        </ns:SubAdministrativeArea>
                    </ns:AdministrativeArea>
                </ns:Country>
            </ns:AddressDetails>
        </Placemark>
    </Response>
</kml> 

For more Information

• XPath Based Mapping - Geocode Example
• Map to Element based on an Attribute Value with EclipseLink JAXB (MOXy)
• XPath Based Mapping

Answer 2

Try Castor Mapping .

Answer 3

You could use a tool like Castor or JAXB to map the XML to a java class. Castor is fairly easy to use.