I am trying to write a class that can serailize and deserailize settings to XML using Java. I have this code successfully written in C# and it is very useful so I would like something similar in my java app.
I have the following base class that every class I want t serialize to XML must implement.
package serializers;
import java.lang.reflect.ParameterizedType;
abstract class XmlSerializableObject<T> {
abstract T getDefault();
abstract String getSerializedFilePath();
String getGenericName() {
return ((Class<T>) ((ParameterizedType) getClass()
.getGenericSuperclass()).getActualTypeArguments()[0]).getTypeName();
}
ClassLoader getClassLoader() {
return ((Class<T>) ((ParameterizedType) getClass()
.getGenericSuperclass()).getActualTypeArguments()[0]).getClassLoader();
}
}
where the getGenericName
and getClassLoader
are for use with instantiating the JAXBContext
. I then have a basic implementation of this as a settings provider
public class SettingsProvider extends XmlSerializableObject<SettingsProvider> {
private Settings settings;
@Override
public SettingsProvider getDefault() {
return null;
}
@Override
public String getSerializedFilePath() {
return "C:\\Data\\__tmp.settings";
}
public Settings getSettings() {
return settings;
};
public void setSettings(Settings settings) {
this.settings = settings;
}
}
class Settings {
private String tmp;
public String getTmp() {
return tmp;
}
public void setTmp(String tmp) {
this.tmp = tmp;
}
}
Now I have the following serializer class
package serializers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.File;
public class XmlSerializer {
private static final Logger logger = LoggerFactory.getLogger(XmlSerializer.class);
public static <T extends XmlSerializableObject> void Serialize(T o) {
String filePath = o.getSerializedFilePath();
File file = new File(filePath);
try {
String name = o.getGenericName();
ClassLoader classLoader = o.getClassLoader();
// THE FOLLOWING LINE throws.
JAXBContext jaxbContext = JAXBContext.newInstance(name, classLoader); // also tried JAXBContext.newInstance(name);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.marshal(o, file);
} catch (JAXBException e) {
logger.error("Serialization failed", e);
}
}
// Deserialize below.
}
I then have the following test to check the results of serialization
package serializers;
import org.junit.Before;
import org.junit.Test;
public class XmlSerializerTest {
private Settings settings = new Settings();
private SettingsProvider provider;
@Before
public void setUp() throws Exception {
settings.setTmp("testing");
provider = new SettingsProvider();
provider.setSettings(settings);
}
@Test
public void serialize() throws Exception {
XmlSerializer.Serialize(provider);
}
}
The problem is the call to JAXBContext jaxbContext = JAXBContext.newInstance(name, classLoader);
which throws
javax.xml.bind.JAXBException: Provider com.sun.xml.internal.bind.v2.ContextFactory could not be instantiated: javax.xml.bind.JAXBException: "serializers.SettingsProvider" doesnt contain ObjectFactory.class or jaxb.index - with linked exception: [javax.xml.bind.JAXBException: "serializers.SettingsProvider" doesnt contain ObjectFactory.class or jaxb.index]
I have tried with and without the ClassLoader
object to no avail. How can I serialize a generic type in this way?
Thanks for your time.