详解Java中String JSONObject JSONArray List<实体类>转换

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JSON使用阿里的fastJson为依赖包

gradle依赖管理如下：

 compile group: 'com.alibaba', name: 'fastjson', version:'1.2.41'

1、String转JSONObject

前言：String 是JSONObject格式的字符串

eg:

 JSONObject jSONObject = JSONObject.parseObject(String);

2、String转JSONArray

前言：String 是JSONArray格式的字符串

eg:

 JSONArray jsonArray= JSONArray.parseArray(String);

3、JSONObject中的数组提取为JSONArray

eg:

 { "AreaName": "北京", "CityId": 110100, "NoMarket": false, "OldCityId": 646, "Pinyin": "beijing", "ProvinceId": 110000, "Result": [ { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "Stelvio 钜惠23.4万起", "Url": "//www.autohome.com.cn/market/201904/100223763.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "马驹桥林肯中心年中大促", "Url": "//www.autohome.com.cn/market/201906/100230932.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "星越平价销售13.58万元起", "Url": "//www.autohome.com.cn/dealer/201906/367011492.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "哈弗F5限时优惠8000元", "Url": "//www.autohome.com.cn/dealer/201906/366897778.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "购元新能源价格暂无优惠", "Url": "//www.autohome.com.cn/dealer/201906/366897034.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "瑞虎3xe冰点价促销中！", "Url": "//www.autohome.com.cn/dealer/201906/366889724.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "购奔奔EV现钜惠5.1万元", "Url": "//www.autohome.com.cn/dealer/201906/366843204.html" }, { "ItemName": "优惠", "ItemUrl": "/list/a646c12-1.html", "Title": "购宝马7系价格暂无优惠", "Url": "//www.autohome.com.cn/dealer/201906/366588080.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "途观L价格直降7.6万元", "Url": "//www.autohome.com.cn/dealer/201906/366568937.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "购凯迪拉克XTS降8万", "Url": "//www.autohome.com.cn/dealer/201906/366500646.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "汉兰达可试驾购车无优惠", "Url": "//www.autohome.com.cn/dealer/201906/366384207.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "宝马M4价格稳定无优惠", "Url": "//www.autohome.com.cn/dealer/201906/366156789.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "奥迪A8促销直降26.33万元", "Url": "//www.autohome.com.cn/dealer/201906/366925378.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "英菲尼迪Q50L可降6.3万", "Url": "//www.autohome.com.cn/dealer/201906/366863516.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "帝豪新能源价格降8.25万", "Url": "//www.autohome.com.cn/dealer/201906/366877669.html" }, { "ItemName": "预定", "ItemUrl": "/list/a646c14-1.html", "Title": "撼路者在售现钜惠5万", "Url": "//www.autohome.com.cn/dealer/201906/366912121.html" } ] }

提取Result对应的数组

 JSONArray jsonArray= jsonObject.getJSONArray("Result");

4、JSONArray提取为JSONObject

eg:

 JSONObject jsonObject = jsonArray.getJSONObject(0);

5、JSONObject获取value

1、object.getString("key")

2、object.get("key")

6、获取JSONObject的ket value

 JSONArray dateArr = new JSONArray(); Set key = dateArr .keySet(); for (String keyObj:key) { JSONArray hisData = history.getJSONArray(keyObj); }

7、遍历JSONArray

 第一种for循环 JSONArray seriesArr = new JSONArray(); for(int i=0;i

8、

 Map paraMap = new HashMap(); JSONObject.toJSONString(paraMap)

自动过滤参数为null的数值

8、javaBean转为JSONObject

未完待续・・・・・・

9、List<实体类>转String

 import com.alibaba.fastjson.JSONObject; List<实体类> value1 = 。。。。。。 JSONObject.toJSONString(value1 )10、JSONArray转List<实体类>

看你开心用哪个，object和array的区别没有细究

10、JSONArray转List<实体类>

 import com.alibaba.fastjson.JSONArray; JSONArray objects = JSONArray.parseArray(categoryConstantInfoFromRedis); List<实体类> categoryConstantInfos = objects.toJavaList(实体类名.class); 众里寻他千百度！！！toJavaList