Java的JSON对象

Question

Can anyone help me how to create a JSON Object from the database.

This is what the JSON output should look like.

       [{
text_layerG: 'Kanpur Analyst Roads', 
cls: 'folder',
children: [{
    text    :   'Road Major',
    layers  :   'analyst_kanpur:road_major',
    leaf    :   true,
    checked : false
},{
    text    : 'Road_minior',
    leaf    : true,
    layers  :   'analyst_kanpur:road_minor',
    checked : false
},{
    text    : 'Road_colony',
    leaf    : true,
    layers  :   'analyst_kanpur:road_colony',
    checked: false
}]

I need to populate text and layers field from database

this is my select Query

String str="Select id, tablename, layername,layer_display_name,layer,visibility,isbaselayer, group_name " +
                " from layermeta " +
                " join  layer_groups on layer_group_id=group_id " +
                " where id not in (72, 73,79) " +
                " order by sequence";

where the text_layerG is group_name and

String text=rsm.getString("layer_display_name");
            String layers=rsm.getString("layer");
            boolean leaf=true;
            boolean checked=false;
            String groupname=rsm.getString("group_name");
            JSONObject jObj = new JSONObject();
            jObj.put("text", text);
            jObj.put("layers", layers);
            jObj.put("leaf", leaf);
            jObj.put("checked",checked);
            jArray.put("children",jObj);
            JSONObject jObjDevice = new JSONObject();
            jObjDevice.put("children", jArray);

this is what i wrote and i got stuck in middle

Please Help me

Answer 1

Maybe JsonArray object is what you need. Check this for more examples.

Answer 2

What you have done is almost correct. Just add the cls and text_layerG in the jObjDevice object along with children and finally add all of them in an Jsonarray.

Answer 3

JSONArray children = new JSONArray();
        while(rsm.next()){
            String g=rsm.getString("group_name");
            //Groups
            JSONObject gObj=new JSONObject();
            gObj.put("text", g);
            //gObj.put("checked", false);
            //gObj.put("checked", true);
            gObj.put("expanded", true);
            gObj.put("cls", "folder");
            JSONArray e=new JSONArray();
            gObj.put("children",e);
            if(groupArr.length()>0){
                boolean found=false;
                for(int i=0;i<groupArr.length();i++){
                    if(groupArr.getJSONObject(i).getString("text").equals(g)){
                        found=true;
                    }
                }
                if(!found) groupArr.put(gObj);
            }else{
                groupArr.put(gObj);
            }


            //Children
            JSONObject cl=new JSONObject();
                cl.put("text", rsm.getString("layer_display_name"));
                cl.put("layer", rsm.getString("layer"));
                cl.put("leaf", true);
                //cl.put("checked", rsm.getBoolean("visibility"));
                cl.put("checked",true);
                cl.put("group", g);
            children.put(cl);
        }

        for(int i=0;i<children.length();i++){
            JSONObject cl= children.getJSONObject(i);
            for(int j=0;j<groupArr.length();j++){
                if(cl.getString("group").equals(groupArr.getJSONObject(j).getString("text"))){
                    groupArr.getJSONObject(j).getJSONArray("children").put(cl);
                }
            }
        }

this is how i done and its working like a charm thanku friends