java组装json和提取一个json的例子

package jsonparsed;import net.sf.json.JSONException;   import net.sf.json.JSONObject; import net.sf.json.JSONArray;public class jsonparsed {// 创建JSONObject对象    private static JSONObject createJSONObject() {        JSONObject jsonObject = new JSONObject();        jsonObject.put("ret", new Integer(0));        jsonObject.put("msg", "query");        JSONObject dataelem1=new JSONObject();        //{"deviceid":"SH01H20130002","latitude":"32.140","longitude":"118.640","speed":"","orientation":""}        dataelem1.put("deviceid", "SH01H20130002");        dataelem1.put("latitude", "32.140");        dataelem1.put("longitude", "118.640");         JSONObject dataelem2=new JSONObject();        //{"deviceid":"SH01H20130002","latitude":"32.140","longitude":"118.640","speed":"","orientation":""}        dataelem2.put("deviceid", "SH01H20130002");        dataelem2.put("latitude", "32.140");        dataelem2.put("longitude", "118.640");             // 返回一个JSONArray对象        JSONArray jsonArray = new JSONArray();                jsonArray.add(0, dataelem1);        jsonArray.add(1, dataelem2);        jsonObject.element("data", jsonArray);                return jsonObject;    }public static void main(String [] args){JSONObject jsonObject = jsonparsed.createJSONObject();//静待  方法，直接通过类名+方法调用    // 输出jsonobject对象    System.out.println("jsonObject：" + jsonObject);    // 添加JSONArray后的值    // 根据key返回一个字符串    String username = jsonObject.getString("ret");    System.out.println("username==>" + username);}}