Java JDBC如何显示Json格式的结果

Question

I am using the postgres database and my actual queries are now returned in Json format and I do not know how to display that to the screen. For instance before I would do this

    org.json.JSONObject jo = null;
    org.json.JSONArray ja = new org.json.JSONArray();

String myquery = "select DISTINCT ON(city,state)latitudes,longitudes,thirtylatmin,thirtylatmax,thirtylonmin,thirtylonmax,city,state from zips where city ilike 'Orl%'  order by city,state,ziptype asc limit 10";
            conn = db.getConnection();


            ps = conn.prepareStatement(myquery);
            rs = ps.executeQuery();

            while (rs.next()) {
                jo = new org.json.JSONObject();
                jo.put("city", rs.getString("city"));
                jo.put("state", rs.getString("state").trim());
                jo.put("latitudes", rs.getFloat("latitudes"));
                jo.put("longitudes", rs.getFloat("longitudes"));

                jo.put("thirtylatmin", rs.getFloat("thirtylatmin"));

                jo.put("thirtylatmax", rs.getFloat("thirtylatmax"));
                jo.put("thirtylonmin", rs.getFloat("thirtylonmin"));
                jo.put("thirtylonmax", rs.getFloat("thirtylonmax"));
                ja.put(jo);
            }
            org.json.JSONObject mainObj = new org.json.JSONObject();
            mainObj.put("location_update", ja);


            String total = mainObj.toString();

            if (ps != null) {
                ps.close();
            }
            conn.close();
            return ok(total);

As you can see I would do my query then convert it to Json format and show it on the browser. My code now is like this

String myquery = "select json_build_object('Profile', array_to_json(array_agg(t))) from (select DISTINCT ON(city,state)latitudes,longitudes,thirtylatmin,thirtylatmax,thirtylonmin,thirtylonmax,city,state from zips where city ilike 'Orl%' order by city,state,ziptype asc limit 10)t";

                conn = db.getConnection();


                ps = conn.prepareStatement(myquery);

                rs = ps.executeQuery();
String results=null;
                while (rs.next()) {

                }



                String total = results.toString();
                // System.err.println(total);
                return ok(total);

My query now returns in Json format so there is no need to convert to Json, how can I get the results of that query to return to the browser . I am new to JDBC and my other question is that I know that JDBC is blocking but is there a limit to the number of request per second that it can handle ? Assuming that I keep adding more CPU's ?

Answer 1

JDBC does not support JSON datatype, just get it as string.

rs = ps.executeQuery();
String results=null;
if (rs.next()) {
    result = rs.getString(1);
}
String total = results.toString();