如何使用JSONObject使用servlet在Java中创建正确的JsonArray

如何使用JSONObject在Java中创建类似以下的JSON对象？如何使用JSONObject使用servlet在Java中创建正确的JsonArray

[ 
    { 
    "title": "ZAKI", 
    "start": "2010-05-01", 
    "placemarks": [ 
     { 
     "polyline": [ 
      { 
      "lat": 48.22467264956519, 
      "lon": 16.32568359375 
      }, 
      { 
      "lat": 47.517200697839414, 
      "lon": 18.984375 
      }, 
      { 
      "lat": 45.84410779560204, 
      "lon": 15.9521484375 
      }, 
      { 
      "lat": 48.22467264956519, 
      "lon": 16.32568359375 
      } 
     ] 
     }, 
     { 
     "point": { 
      "lat": 48.22467264956519, 
      "lon": 16.32568359375 
     } 
     }, 
     { 
     "point": { 
      "lat": 47.517200697839414, 
      "lon": 18.984375 
     } 
     }, 
     { 
     "point": { 
      "lat": 45.84410779560204, 
      "lon": 15.9521484375 
     } 
     } 
    ] 
    } 
]

我正在使用servlet。

这是我的servlet代码

JSONArray arrayObj = new JSONArray(); 
      for (int i = 0; i < listDataTracking.size(); i++) { 
       JSONObject obj = new JSONObject(); 
       EntityTracking dataTracking = listDataTracking.get(i); 

       if (dataTracking.getIdTracking() == null) { 
        obj.put("Id", ""); 
       } else { 
        obj.put("Id", dataTracking.getIdTracking()); 
        obj.put("title", dataTracking.getUser_name().getUserName().toUpperCase()); 
        obj.put("start", sdf.format(dataTracking.getTglSend())); 
//          
        String lat = ""; 
        String lon = ""; 
        String jamSend = ""; 
        Long id = 0l; 
//      

        String queryStmnt_geoTracking = "SELECT entityGeoTracking.id FROM EntityGeoTracking entityGeoTracking " 
          + "WHERE entityGeoTracking.idTracking.idTracking=\"" + dataTracking.getIdTracking() + "\""; 
        javax.persistence.Query query_geoTracking = em.createQuery(queryStmnt_geoTracking); 
        System.out.println("Isi queryStmnt_geoTracking" + queryStmnt_geoTracking); 
        List<EntityGeoTracking> cekid = query_geoTracking.getResultList(); 
        if (cekid.isEmpty()) { 
         System.out.println("Isi cekid == null"); 
         return; 
        } 
        System.out.println("Isi cekid" + cekid); 
        EntityGeoTracking dataGeoTraking = em.find(EntityGeoTracking.class, cekid); 
        if (lat.isEmpty()) { 

         lat = dataGeoTraking.getGetLatitude(); 
        } 
        if (lon.isEmpty()) { 
         lon = dataGeoTraking.getGetLongitude(); 
        } 
        if (id == 0l) { 
         id = dataGeoTraking.getId(); 
        } 
        if (jamSend.isEmpty()) { 
         jamSend = dataGeoTraking.getJamSend(); 
        } 
        System.out.println("chek value lat, lon, id, jamSend" + lat + "" + lon + "" + id + "" + jamSend); 

        javax.json.JsonArray value = Json.createArrayBuilder() 
          .add(Json.createObjectBuilder() 
          .add("polyline", Json.createObjectBuilder() 
          .add("lat", lat) 
          .add("lon", lon))) 
          .add(Json.createObjectBuilder() 
          .add("point", Json.createObjectBuilder() 
          .add("lat", lat) 
          .add("lon", lon))) 
          .build(); 


        obj.put("placemarks", value); 

       } 



       arrayObj.add(obj); 
      } 

      em.close(); 

      JSONObject rows = new JSONObject(); 

//   rows.put("results", arrayObj);//results 
//   rows.put("results", listDataTracking.size());//results 
//   rows.put("rows", arrayObj); 
//   writer.print(rows.toString()); 
//   rows.put("", listDataTracking.size());//results 
      rows.put("", arrayObj); 
      System.out.println(" List : " + arrayObj.toString()); 
      writer.print(arrayObj); 
      writer.close(); 

//   } 
//   br.close(); 

     } catch (Exception ex) { 
      ex.getMessage(); 
      System.out.println("ERROR: " + ex.getMessage()); 
     } finally { 
      if (em != null && em.isOpen()) { 
       em.close(); 
      } 
     } 
    }

我的输出JSON格式

[ 
    { 
    "Id": 1, 
    "title": "ZAKI", 
    "start": "2016-06-15", 
    "placemarks": [ 
     { 
     "polyline": { 
      "lat": { 
      "chars": "-6.2206080", 
      "string": "-6.2206080", 
      "valueType": "STRING" 
      }, 
      "lon": { 
      "chars": "106.7810640", 
      "string": "106.7810640", 
      "valueType": "STRING" 
      } 
     } 
     }, 
     { 
     "point": { 
      "lat": { 
      "chars": "-6.2206080", 
      "string": "-6.2206080", 
      "valueType": "STRING" 
      }, 
      "lon": { 
      "chars": "106.7810640", 
      "string": "106.7810640", 
      "valueType": "STRING" 
      } 
     } 
     } 
    ] 
    } 
]

我已经尝试过很多次，但我一直不成功。请帮忙！

来源

2016-06-14 newbiecihuy

无论您是否使用servlet似乎都是无关紧要的。假设你加载了正确的数据（你可以自己检查一下，例如通过调试你的代码），这个问题似乎是关于如何构建你想要的JSON数组。也就是说你应该检查'results [0] .toString（）;'等实际返回的结果。 'entityGeoTracking.getLatitude'（这是一个奇怪的属性名称btw）可能不只是返回一个数字或字符串，而是一些包装对象。 – Thomas

{ 
    "title": "ZAKI", 
    "start": "2010-05-01", 
    "placemarks": [ 
     { 
      "polyline": [ 
       { 
        "lat": 48.2246726495652, 
        "lon": 16.32568359375 
       }, 
       { 
        "lat": 47.5172006978394, 
        "lon": 18.984375 
       }, 
       { 
        "lat": 45.844107795602, 
        "lon": 15.9521484375 
       }, 
       { 
        "lat": 48.2246726495652, 
        "lon": 16.32568359375 
       } 
      ] 
     }, 
     { 
      "point": { 
       "lat": 48.2246726495652, 
       "lon": 16.32568359375 
      } 
     }, 
     { 
      "point": { 
       "lat": 47.5172006978394, 
       "lon": 18.984375 
      } 
     }, 
     { 
      "point": { 
       "lat": 45.844107795602, 
       "lon": 15.9521484375 
      } 
     } 
    ] 
}

首先使用some formatting tool来格式化您的json，以便您可以轻松地了解预期与实际输出的差异。

对于折线对象，您应该拥有一个数组而不是对象。

Json.createObjectBuilder().add("polyline", 
           Json.createObjectBuilder().add("lat", lat).add("lon", lon)) 
          )

来源

2016-06-14 08:44:08 Tomz

如何使用JSONObject使用servlet在Java中创建正确的JsonArray

回答

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