get JSON data from struts

问题

I can get part of data from the Action function, by using the JSONArray.fromObject method, using AJAX to receive the json object. But it is very strange that the same solution did not work with beans files.

The Error is below. I searched for a solution to the three main errors. Maybe I need to import the java.lang.reflect.InvocationTargetException library, or add some libs in a package, or maybe Java,util.data conflicts with util.sql.data. I am not sure if it will work even I made all of the potential suggestions above.

Error info:

 [   00000015 SystemErr     R 

net.sf.json.JSONException: java.lang.reflect.InvocationTargetException
    at net.sf.json.JSONObject.defaultBeanProcessing

(JSONObject.java:818)
    at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
    at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
    at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
    at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
    at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
    at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
    at net.sf.json.JSONObject.defaultBeanProcessing

(JSONObject.java:765)
    at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
    at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
    at net.sf.json.JSONArray._processValue(JSONArray.java:2513)
    at net.sf.json.JSONArray.processValue(JSONArray.java:2538)
    at net.sf.json.JSONArray.addValue(JSONArray.java:2525)
    at net.sf.json.JSONArray._fromCollection(JSONArray.java:1056)
    at net.sf.json.JSONArray.fromObject(JSONArray.java:123)
    at net.sf.json.JSONArray.fromObject(JSONArray.java:105)
    at 

(SearchAction.java:675)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke

(NativeMethodAccessorImpl.java:60)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke

(DelegatingMethodAccessorImpl.java:37)
    at java.lang.reflect.Method.invoke(Method.java:611)
    at org.apache.struts.actions.DispatchAction.dispatchMethod
Caused by: java.lang.reflect.InvocationTargetExceptionat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke

(NativeMethodAccessorImpl.java:60)

Caused by: java.lang.IllegalArgumentException
    at java.sql.Date.getHours(Date.java:79)
    ... 69 more`]

回答1:

Try this, will help you in Struts 2.0.14 with jsonplugin-0.32.jar.

struts.xml:

<struts>
     <package name="example" extends="json-default">
        <action name="HelloWorld" class="example.HelloWorld"  >
            <result type="json" />
        </action>
              <action name="HelloWorld1" class="example.HelloWorld"  >
            <result name="success" >example/HelloWorld.jsp</result>
        </action>
    </package>
</struts>

action class Helloworld.java:

package prabhakar;

import glb.DB;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Prabhakar
 */
public class HelloWorld  {


    private List<StateMaster> stateList= new ArrayList<StateMaster>();
    private List<RegnMaster> regnList= new ArrayList<StateMaster>();

    private Integer stateId;
    public Integer getStateId()
    {
    return this.stateId;
    }
    public void setStateId(Integer stateId)
    {
    this.stateId=stateId;
    }
    public List<StateMaster> getStateList() {
        return stateList;
    }

    public void setStateList(List<StateMaster> stateList) {
        this.stateList = stateList;
    }
     public void setRegnList(List<RegnMaster> regnList) {
        this.regnList = regnList;
    }
    public List<RegnMaster> getRegnList() {
        return regnList;
    }

    public String execute() throws Exception {

        stateList=DB.getStateData()//
        if(stateId !=null)
          {
         regnList=DB.getRegnByStateId(stateId);
          }

        //setMessage(getText(MESSAGE));
        return "success";
    }

    /**
     * Provide default valuie for Message property.
     */

}

You can directly call HelloWorld.action to view the JSON data or else you can bind the JSON data to a form element below.

JSP page HelloWorld.jsp:

  /*
     Prabhakar
  */

<%@ page contentType="text/html; charset=UTF-8" %>

<%@ taglib prefix="s" uri="/struts-tags" %>
<script>
<%@include file="../js/jquery-1.7.1.min.js"%>
</script>
    <html>

<!-- JavaScript Plugins -->
  <script>
       function getLoad(){


       var stateId = $('#state').val();

$.getJSON('HelloWorld.action', {'stateId': stateId},
    function(data) {

           var divisionList = (data.regnList);

                var options = $("#regn");
                options.find('option')
    .remove()
    .end();
     options.append($("<option />").val("-1").text("--Select--"));
$.each(divisionList, function() {

    options.append($("<option />").val(this.regnId).text(this.regnName));
});
    }
);}
   </script>

<!-- jQuery-UI Dependent Scripts -->

    <body>
        State List <s:select name="stateId" list="stateList" id="state" listKey="stateId" onchange="getLoad()" listValue="stateName" headerKey="0" headerValue="--select--" />
        Regn List <s:select name="regnId"  list="regnList" listKey="regnId" id="regn" listValue="regnName" headerKey="0" headerValue="--select--" />
    </body>
</html>

Happy coding :)

来源：https://stackoverflow.com/questions/11026542/get-json-data-from-struts