java jdbc如何正確將數據添加到JsonObject

Question

我正在使用JDBC從MySQL數據庫中檢索2條記錄，並將它們轉換為JsonObject，但是代碼無法正常工作，例如：我得到了這個結果

{"locations":[{"city":"OrlandoOrlando","state":"WVFL"}]}

代替

{"locations":[{"city":"Orlando","state":"WV"},{"city":"Orlando","state":"WV"}]}

我知道自己的狀態，但似乎可以找到糾正方法，這是我的代碼

String city="";
String state="";
try {
   JSONObject jo = new JSONObject();
   Connection conn = DB.getConnection();
   ResultSet rs;
  PreparedStatement ps = conn.prepareStatement("select city,state from zips limit 2");
   rs = ps.executeQuery();
   while (rs.next()) {
// The problem is in this area the: city+ and state+
       city+= rs.getString("city");
       state+= rs.getString("state");
   }
   jo.put("city",city);
   jo.put("state", state);
   JSONArray ja = new JSONArray();
   ja.put(jo);
   JSONObject mainObj = new JSONObject();
   mainObj.put("locations", ja);

問題出在上面的city +和state +字符串中，但是如果我這樣做

while (rs.next()) {
   city= rs.getString("city");
   state= rs.getString("state");
 }

它修復了所有問題，但只返回了1條記錄，而不是2條，看起來像這樣

{"locations":[{"city":"Orlando","state":"WV"}]}

任何建議都很好。

Answer 1

我已經進行了更改，以通過SQL輸出構建JSONArray。

JSONObject jo = new JSONObject();
Connection conn = DB.getConnection();
ResultSet rs;
PreparedStatement ps = conn.prepareStatement("select city,state from zips limit 2");
rs = ps.executeQuery();
JSONArray ja = new JSONArray();
while (rs.next()) {
    jo.put("city", rs.getString("city"));
    jo.put("state", rs.getString("state"));
    ja.put(jo);
}

JSONObject mainObj = new JSONObject();
mainObj.put("locations", ja);

Answer 2

JSONObject jo = null;
Connection conn = DB.getConnection();
ResultSet rs;
PreparedStatement ps = conn.prepareStatement("select city,state from zips limit 2");
rs = ps.executeQuery();
JSONArray ja = new JSONArray();
while (rs.next()) {
    jo = new JSONObject();
    jo.put("city", rs.getString("city"));
    jo.put("state", rs.getString("state"));
    ja.put(jo);
}
JSONObject mainObj = new JSONObject();
mainObj.put("locations", ja);