使用Smook和Freemarker将Java对象转换为XML的模型是什么？

Question

I am having trouble finding clear documentation on how to do the following transformation:

Java Object -> Smooks/Freemarker Template -> XML Output

Here is the example I am trying:

Java POJO (I have a separate DAO clas that populates this object):

package Transformer;

public class JavaObject {
    String name; 
}

Main transformer class:

package Transformer;

import java.io.IOException;
import java.io.StringWriter;

import javax.xml.transform.stream.StreamResult;

import org.milyn.Smooks;
import org.milyn.container.ExecutionContext;
import org.milyn.payload.JavaSource;
import org.xml.sax.SAXException;

public class Transformer {

     protected static String runSmooksTransform(Object javaObject) throws IOException, SAXException {
        Smooks smooks = new Smooks("smooks-config.xml");
        try {
            ExecutionContext executionContext = smooks.createExecutionContext();
            StringWriter writer = new StringWriter();
            smooks.filterSource(executionContext, new JavaSource("smooks-config.xml"), new StreamResult(writer));
            return writer.toString();
        } finally {
            smooks.close();
        }
    }

    public static void main(String args[]) {
        try {
            Transformer.runSmooksTransform(javaObject);
        } catch(Throwable ex){
            System.err.println("Uncaught exception - " + ex.getMessage());
            ex.printStackTrace(System.err);
        }
    }
}

So here is the point where I am confused... I have seen a few different ways to "map" the template

here are some examples I have seen:

A .ftl template file with mapping like this:

     <Nm> ${Name} </Nm>

An XML mapping like this:

    <medi:segment minOccurs="0" maxOccurs="1" segcode="" xmltag="Group">
                <medi:field xmltag="Name" />
    </medi:segment>

Mapping in the smooks-config.xml itself:

 <?xml version="1.0"?>
 <smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.0.xsd" 
 xmlns:ftl="http://www.milyn.org/xsd/smooks/freemarker-1.1.xsd">

     <resource-config selector="global-parameters">
         <param name="stream.filter.type">SAX</param>
     </resource-config>

     <reader mappingModel="example.xml" />

     <ftl:freemarker applyOnElement="order">
         <ftl:template>
           <Nm>${name}</Nm>
         </ftl:template>
     </ftl:freemarker>

 </smooks-resource-list>

So can anyone please explain the correct way to use Smooks + a Freemarker template to convert a java object to a specified XML output?

Or point me to documentation/example specific to this use case?

Thank you

Answer 1

I don't know anything about how it's done in Smooks, but it's very likely that you need to add a public String getName() { return name; } public String getName() { return name; } to the JavaObject class, or else it won't be visible form the FreeMarker template. It actually depends on the FreeMarker configuration settings (and I don't know how Smooks configures it), so anything is possible in theory, but it's likely that you need a getter method, but if not then at least the field need to be public .

Also you don't pass javaObject to Smooks in your example code, though I guess it's not a the real code.