/** * Save the result to be used later. * @param actionConfig current ActionConfig * @param methodResult the result of the action. * @return the result code to process. */
protected String saveResult(ActionConfig actionConfig, Object methodResult) {  if (methodResult instanceof Result) {  this.explicitResult = (Result) methodResult;  // Wire the result automatically
        container.inject(explicitResult);  return null;  } else {  return (String) methodResult;  }
}

this.explicitResult = (Result) methodResult;  // Wire the result automatically
container.inject(explicitResult);
return null;  

package com.kiloway.struts;  import java.io.PrintWriter;  import javax.servlet.http.HttpServletResponse;  import net.sf.json.JSONObject;
import net.sf.json.JsonConfig;  import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.StrutsResultSupport;  import com.opensymphony.xwork2.ActionInvocation;  public class JsonResult extends StrutsResultSupport {  private Object result;  private JsonConfig jsonConfig;  public Object getResult() {  return result;  }  public JsonResult(JsonConfig jsonConfig) {  super();  this.jsonConfig = jsonConfig;  }  public void setResult(Object result) {  this.result = result;  }  private static final long serialVersionUID = 7978145882434289002L;  @Override  protected void doExecute(String finalLocation, ActionInvocation invocation)  throws Exception {  HttpServletResponse response = null;  try {  response = ServletActionContext.getResponse();  PrintWriter printWriter = response.getWriter();  if (jsonConfig != null) {  printWriter.write(JSONObject.fromObject(result).toString());  } else {  printWriter.write(JSONObject.fromObject(result, jsonConfig)  .toString());  }  }catch(Exception e){  throw new Exception("json parse error!");  } finally {  response.getWriter().close();  }}
}  

<package name="default" namespace="/" extends="struts-default">  <result-types>  <result-type name="jsonResult" class="com.kiloway.struts.JsonResult"/>  </result-types>  <action name="student" class="com.kiloway.struts.Student">  <result name="json" type="jsonResult"/>  </action>
</package> 

public JsonResult getJson()  {  UserInfo f = new UserInfo();  f.setName("小睿睿");  f.setPassword("哈哈");  JsonResult jsonResult  = new JsonResult();  jsonResult.setResult(f);  return jsonResult;  }