Question

I have created custom result class to serialize json data to xml. I want to configure this result class as a result type for some specific actions via conventions plug ins.
But it is giving errors at the time of starting container. My code and error is given below.

My custom Result class:

package actions;

import example.*;
import java.io.PrintWriter;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.util.ValueStack;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver;


public class JSONResult implements Result {

public static final String DEFAULT_PARAM = "classAlias";
String classAlias;

public String getClassAlias() {
    return classAlias;
}

public void setClassAlias(String classAlias) {
    this.classAlias = classAlias;
}

public void execute(ActionInvocation invocation) throws Exception {
    System.out.println("executing JSONResult execute()");
    ServletActionContext.getResponse().setContentType("text/plain");
    PrintWriter responseStream = ServletActionContext.getResponse().getWriter();
    /* Retrieve Objects to Serialize to JSON from ValueStack */
    ValueStack valueStack = invocation.getStack();
    Object jsonModel = valueStack.findValue("jsonModel");

    XStream xstream = new XStream(new JsonHierarchicalStreamDriver());

   /*
     * If there's no parameter passed in, just write the objects under a
     * default name.
     */
    if (classAlias == null) {
        classAlias = "object";
    }
    xstream.registerConverter(new XStreamHashConverter());
    xstream.alias(classAlias, jsonModel.getClass());

    /* Write to the response stream */
    System.out.println("xstream.toXML(jsonModel) == "+xstream.toXML(jsonModel));
    responseStream.println(xstream.toXML(jsonModel));
}
}

my Actions class with annotations follows:

package actions;

import com.opensymphony.xwork2.ActionSupport;
import java.util.HashMap;
import java.util.Map;
import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.convention.annotation.Namespace;
import org.apache.struts2.convention.annotation.ParentPackage;
import org.apache.struts2.interceptor.ParameterAware;


@ParentPackage("actions")
@Namespace("/actions")
public class ZipDataSupplier extends ActionSupport implements ParameterAware
{
 private Map parameters;
 private Object jsonModel;

 public Map getParameters()
 {
    return this.parameters;
 }
 public void setParameters(Map parameters)
 {
   this.parameters=parameters;
 }
public Object getJsonModel()
{
   return this.jsonModel;
}
public void setJsonModel(Object jsonModel)
{
   this.jsonModel = jsonModel;
}

@Action(value="/getZipData",results={@Result(name="success",location="ajaxCall", **type="actions.JSONResult")**})
public String getZipData()
{
   System.out.println("inside getZipData ... ...");
   Map map =  getParameters();
   System.out.println("parameter map = "+map);
   String htmlIds = ((String[])map.get("htmlIds"))[0];
   System.out.println("htmlIds = "+htmlIds);
   String jsonIds = ((String[])map.get("jsonIds"))[0];
   System.out.println("jsonIds = "+jsonIds);
   ZipData zipData = new ZipData();
   zipData.getCity().put("Dulles", "Dulles");
   zipData.getCity().put("New York", "New York");
   setJsonModel(zipData);
   return SUCCESS;
 }
}

class ZipData
{
private String zipCode = "20101";
private String stateCode = "VA";
private String stateName = "Virginia";

private HashMap<String,String> city=new HashMap<String, String>();

//private JSONObject city = null;//JSONArray.fromObject( getCityMap());

/**
 * @return the zipCode
 */
public String getZipCode() {
    return zipCode;
}

/**
 * @param zipCode the zipCode to set
 */
public void setZipCode(String zipCode) {
    this.zipCode = zipCode;
}

/**
 * @return the stateCode
 */
public String getStateCode() {
    return stateCode;
}

/**
 * @param stateCode the stateCode to set
 */
public void setStateCode(String stateCode) {
    this.stateCode = stateCode;
}

/**
 * @return the stateName
 */
public String getStateName() {
    return stateName;
}

/**
 * @param stateName the stateName to set
 */
public void setStateName(String stateName) {
    this.stateName = stateName;
}

/**
 * @return the city
 /
public JSONObject getCity() {
    this.city = JSONObject.fromObject( getCityMap());
    return this.city;
}

/**
 * @param city the city to set
 /
public void setCity(JSONObject city) {
    this.city = city;
}

/**
 * @return the cityMap
 */
public HashMap<String, String> getCity() {
    //city.put("Dulles", "Dulles");
    //city.put("ABC", "ABC");
    return city;
}

/**
 * @param city the city to set
 */
public void setCity(HashMap<String, String> city) {
    this.city = city;
}



/**
 * @return the city
 /
public String getCity() {
    return city;
}

/**
 * @param city the city to set
 /
public void setCity(String city) {
    this.city = city;
}

/**
 * @return the city
 /
public Map<String, String> getCity() {
    return city;
}

/**
 * @param city the city to set
 /
public void setCity(Map<String, String> city) {
    this.city = city;
}
 * */
}

Struts.XML file follows:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="true"/>
    <constant name="struts.configuration.xml.reload" value="true"/>
</struts>

Answer 1

As far as I understand, you want to serialize json data to xml using custom class before you rendered somewhere.

So what you can do is, write an action for serialization and give the action as the result page for the main action that returns json format so that the json is also available to the result action. If you want json as string object, use can convert any object, list etc. to json string using GSON API.

If this is not your solution, do comment. We can move furthur.