Android-json解析：原生JSONObject+JSONArray的使用【转】

原文地址：https://blog.csdn.net/sinat_31057219/article/details/71518123

一、JSONObject和JSONArray的数据表示形式

JSONObject的数据是用 { } 来表示的，

例如：

{ "id" : "123", "courseID" : "huangt-test", "title" : "提交作业", "content" : null  }  

而JSONArray，顾名思义是由JSONObject构成的数组，用 [ { } , { } , …… , { } ] 来表示

例如：

 [{  "id" : "123", "courseID" : "huangt-test", "title" : "提交作业"},
{  "content" : null, "beginTime" : 1398873600000  "endTime" } ] 

表示了包含2个JSONObject的JSONArray。

可以看到一个很明显的区别，一个最外面用的是 { } ，一个最外面用的是 [ ] ；

二、如何从字符串jsonString获得JSONObject对象和JSONArray对象

/*json字符串最外层是大括号时：*/
JSONObject jsonObject = new JSONObject(jsonStr);

/*json字符串最外层是方括号时：*/
JSONArray jsonArray = new JSONArray(jsonStr);

三、如何从JSONArray中获得JSONObject对象

遇到方括号时，就要先获取JSONArray，然后再循环遍历出JSONObject

大家可以把JSONArray当成一般的数组来对待，只是获取的数据内数据的方法不一样。

 for (int i = 0; i < jsonArray.length(); i++) {
    JSONObject jsonObject = jsonArray.getJSONObject(i);
 }

注意：

/*JSONObject 获取jsonArray ：需要数组的字段名*/
JSONArray jsonArray = jsonObject.getJSONArray("children");

/*jsonArray获取JSONObject ： 需要遍历数组*/
 for (int i = 0; i < jsonArray.length(); i++) {
    JSONObject jsonObject = jsonArray.getJSONObject(i);
 }

四、通过JsonObject获取JSON内的具体数据：

int mid= jsonObject.getInt ( "id" ) ;
//  这里的mid得到的数据就是123.

String mcourse=jsonObject.getString( " courseID") ;
// 这里的mcourse得到的数据就是huangt-test.

示例一：

{
  "msg": "",
  "code": "succeed",
  "login_status": 0,
  "mall_uid": "epet_0",
  "mall_user": "",
  "sys_time": 1494388655,
  "push_alias": "",
  "push_tags": "version3",
  "categorys": [
    {
      "cateid": 53,
      "name": "狗狗玩具",
      "children": [
        {
          "type": "cateid",
          "id": "210",
          "name": "棉制玩具",
          "photo": "http://i.epetbar.com/nowater/cates/2014-03/24/fcab37ead00d77bcdddf7dabe6c817d7.jpg"
        },
        {
          "type": "cateid",
          "id": "211",
          "name": "橡胶玩具",
          "photo": "http://i.epetbar.com/nowater/2016-07/21/14/874299e54a8cf1488d6b1bead8f8e9bb.jpg"
        },
        {
          "type": "cateid",
          "id": "212",
          "name": "塑料玩具",
          "photo": "http://i.epetbar.com/nowater/cates/2014-03/24/df1ed7120376370a4b5badaae61a0a7e.jpg"
        },
        {
          "type": "cateid",
          "id": "213",
          "name": "手工玩具",
          "photo": "http://i.epetbar.com/nowater/cates/2014-03/24/6709410560b999ab37ffb9747bb2ee71.jpg"
        },
        {
          "type": "cateid",
          "id": "3088",
          "name": "食用玩具",
          "photo": "http://i.epetbar.com/nowater/cates/2014-03/24/a5c7619872749790f6d6fd1ff3eccedc.jpg"
        },
        {
          "type": "cateid",
          "id": "4157",
          "name": "木质玩具",
          "photo": "http://i.epetbar.com/nowater/cates/2014-03/24/e9145de044fd5cec4c9b8ed47360d98f.jpg"
        },
        {
          "type": "cateid",
          "id": "4188",
          "name": "梵米派",
          "photo": "http://i.epetbar.com/nowater/cates/2015-07/28/45c339f6acb56364132b92f04b090c5c.jpg"
        }
      ]
    }
  ],
  "topadv": {
    "advid": "20605",
    "src": "https://img2.epetbar.com/nowater/2017-04/05/14/19427a29344bcc0f385ca4718adca02f.jpg",
    "title": "红脚丫",
    "param": {
      "mode": "web",
      "param": "http://sale.epet.com/m/mould/activity/ztMTAzOA%3D%3D.html?tid=1038"
    }
  },
  "owner": 53
}

解析如下：

注意：MyData类可以借助GsonFormat类生成实体类。

private List<MyData.CategorysBean.ChildrenBean> parseJSONOrgin(String string) {
        List<MyData.CategorysBean.ChildrenBean> childrenBeanList = new ArrayList<MyData.CategorysBean.ChildrenBean>();

        try {
            JSONObject jsonObject = new JSONObject(string);
            JSONArray jsonArray = jsonObject.getJSONArray("categorys");
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonObject1 = jsonArray.getJSONObject(i);

                JSONArray children = jsonObject1.getJSONArray("children");
                for (int j = 0; j < children.length(); j++) {
                    JSONObject jsonObject2 = children.getJSONObject(j);

                    MyData.CategorysBean.ChildrenBean childrenBean = new MyData.CategorysBean.ChildrenBean();
                    childrenBean.setName(jsonObject2.getString("name"));
                    childrenBean.setId(jsonObject2.getString("id"));
                    childrenBean.setPhoto(jsonObject2.getString("photo"));
                    childrenBean.setType(jsonObject2.getString("type"));

                    childrenBeanList.add(childrenBean);
                }
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }

        return childrenBeanList;
    }

示例二：

[
  {
    "id": 582490,
    "name": "单车自驾：魔幻张家界",
    "photos_count": 128,
    "start_date": "2016-04-05",
    "end_date": "2016-04-08",
    "days": 4,
    "level": 4,
    "views_count": 55199,
    "comments_count": 34,
    "likes_count": 441,
    "source": "web",
    "front_cover_photo_url": "http://p.chanyouji.cn/582490/1468260328216p1andi510ihgkc2f5hk6rf198.jpg",
    "featured": false,
    "user": {
      "id": 313643,
      "name": "huchichi",
      "image": "http://tva2.sinaimg.cn/crop.0.12.282.282.50/5c5ee839gw1ec7kq4pasrj207v08d3zv.jpg"
    }
  },
  {
    "id": 666746,
    "name": "【斯里兰卡10天】跨过山和大海",
    "photos_count": 122,
    "start_date": "2016-12-24",
    "end_date": "2017-01-02",
    "days": 10,
    "level": 3,
    "views_count": 33023,
    "comments_count": 32,
    "likes_count": 471,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/666746/1485787660939p1b7ntf07u16kdssn1tfl1ck1q1qd.jpg",
    "featured": false,
    "user": {
      "id": 469471,
      "name": "宇_RainyK",
      "image": "http://a.chanyouji.cn/469471/1460020629.jpg"
    }
  },
  {
    "id": 665223,
    "name": "上帝自留地探访 : 新西兰——快乐咔嚓声",
    "photos_count": 250,
    "start_date": "2016-11-30",
    "end_date": "2016-12-04",
    "days": 5,
    "level": 3,
    "views_count": 23981,
    "comments_count": 30,
    "likes_count": 533,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/1483013211/40p8jhlx7t4e8hntyhp4z31c0.jpg",
    "serial_id": 664971,
    "serial_position": 1,
    "featured": false,
    "user": {
      "id": 131541,
      "name": "片儿川",
      "image": "http://a.chanyouji.cn/131541/1483887153821.jpg"
    }
  },
  {
    "id": 591454,
    "name": "土耳其...我喜欢你，像风走了八千里",
    "photos_count": 195,
    "start_date": "2016-08-08",
    "end_date": "2016-08-22",
    "days": 15,
    "level": 3,
    "views_count": 18822,
    "comments_count": 42,
    "likes_count": 854,
    "source": "web",
    "front_cover_photo_url": "http://p.chanyouji.cn/1472368913/9896F012-522E-46C4-9F29-5F6D86C790DB.jpg",
    "featured": false,
    "user": {
      "id": 208609,
      "name": "晶晶姑姑娘娘",
      "image": "http://a.chanyouji.cn/208609/1493099858.jpg"
    }
  },
  {
    "id": 589708,
    "name": "浪迹非洲最南——“慢得啦”国闲游之一",
    "photos_count": 128,
    "start_date": "2016-07-23",
    "end_date": "2016-07-24",
    "days": 2,
    "level": 3,
    "views_count": 5858,
    "comments_count": 4,
    "likes_count": 65,
    "source": "web",
    "front_cover_photo_url": "http://p.chanyouji.cn/589708/1471963416200p1aqrtl1pq8js1ek0sn913uq1kdmh.jpg",
    "serial_id": 589708,
    "serial_position": 0,
    "featured": false,
    "user": {
      "id": 103122,
      "name": "牵着蜗牛散步的JOY",
      "image": "http://tva1.sinaimg.cn/crop.0.17.640.640.50/794bd26ajw8e7tg9nfqb5j20hs0iqmxg.jpg"
    }
  },
  {
    "id": 598966,
    "name": "霓虹国/留学生  梦游记录",
    "photos_count": 88,
    "start_date": "2016-08-28",
    "end_date": "2017-05-07",
    "days": 253,
    "level": 3,
    "views_count": 16648,
    "comments_count": 10,
    "likes_count": 72,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/1476365877/C9B59738-58E8-47C9-BCD1-5F2AC5CC9526.jpg",
    "featured": false,
    "user": {
      "id": 694154,
      "name": "Y-dec",
      "image": "http://q.qlogo.cn/qqapp/100277927/5475C47B95A36891E2698462184F8785/100"
    }
  },
  {
    "id": 544528,
    "name": "【我的年假】7 重庆—吃一顿地道火锅",
    "photos_count": 385,
    "start_date": "2016-08-31",
    "end_date": "2016-09-03",
    "days": 4,
    "level": 3,
    "views_count": 37214,
    "comments_count": 55,
    "likes_count": 530,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/544528/1474011393910p1asoupfpujrj1rnd5o813qo1jvi5.jpg",
    "serial_id": 544528,
    "serial_position": 0,
    "featured": false,
    "user": {
      "id": 17010,
      "name": "马兰头头2010",
      "image": "http://a.chanyouji.cn/17010/1426768814.jpg"
    }
  },
  {
    "id": 665311,
    "name": "就该这么玩【北海道】",
    "photos_count": 118,
    "start_date": "2016-12-05",
    "end_date": "2016-12-12",
    "days": 8,
    "level": 3,
    "views_count": 24644,
    "comments_count": 6,
    "likes_count": 108,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/1484295471/E2B2C32A-C910-490F-9F13-BC9D3B118C1B.jpg",
    "featured": false,
    "user": {
      "id": 544219,
      "name": "炘仔~",
      "image": "http://a.chanyouji.cn/544219/1489641072.jpg"
    }
  },
  {
    "id": 668998,
    "name": "漫步成都一一我的寻（熊）猫之旅",
    "photos_count": 108,
    "start_date": "2017-02-06",
    "end_date": "2017-02-12",
    "days": 7,
    "level": 3,
    "views_count": 15222,
    "comments_count": 30,
    "likes_count": 146,
    "source": "app",
    "front_cover_photo_url": "http://p.chanyouji.cn/1487129075/720F81CB-EE64-4681-8564-A9A6864AAD33.jpg",
    "featured": false,
    "user": {
      "id": 261578,
      "name": "小柠12345",
      "image": "http://tva1.sinaimg.cn/crop.27.0.238.238.50/bb9ff9e8gw1eggbljiopfj208w06oaam.jpg"
    }
  },
  {
    "id": 297060,
    "name": "「吃遍日本」大阪·神户·名古屋",
    "photos_count": 125,
    "start_date": "2015-04-25",
    "end_date": "2015-05-02",
    "days": 8,
    "level": 4,
    "views_count": 56384,
    "comments_count": 121,
    "likes_count": 948,
    "source": "web",
    "front_cover_photo_url": "http://p.chanyouji.cn/297060/1440912374444p19tuh3ukup7t1l5c1j0u8r6kfs2.jpg",
    "featured": false,
    "user": {
      "id": 312316,
      "name": "CaitlinGao",
      "image": "http://tva3.sinaimg.cn/crop.0.0.640.640.50/96246e0bjw8ensjycmsdmj20hs0hsjs7.jpg"
    }
  }
]

解析如下：

注意：最外层是个方括号。

    private List<News> parseJSONOrgin(String json) {
        List<News> list = new ArrayList<News>();
        try {
            JSONArray jsonArray = new JSONArray(json);
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                News news = new News();
                news.setSource(jsonObject.getString("source"));
                news.setFront_cover_photo_url(jsonObject.getString("front_cover_photo_url"));
                news.setName(jsonObject.getString("name"));
                news.setStart_date(jsonObject.getString("start_date"));
                list.add(news);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return list;
    }

JSONObject获取Float Double类型数据的准确性：

原始数据：{"status":0,"result":[{"x":114.2307489832,"y":29.579081808346}]}  

logger.error(obj.getFloatValue("x"));  

114.23075  

logger.error(obj.getDoubleValue("x"));  

114.23075103759766  

以上2个方法都无法获得完全一致的数值。

Double.valueOf(obj.get("x").toString())  

//这段代码可以准确的获取对应数值。 

示例：

homeTopBannerModel.slide_time =Float.valueOf(jSONObjectTopSlide.get("slide_time").toString());