java 无法在java中访问getJSONArray
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Can't access getJSONArray in java
提问by baron_bartek
I have this Json from URL:
我有这个来自 URL 的 Json：
{
"type":"FeatureCollection",
"features":
[
{
"type":"Feature",
"properties":
[
{
"type":"colliers",
"thumb":"upload\/estate\/135\/thumb_1. Prologis Park Wroclaw I.jpg",
"name_pl":"Prologis Park Wroc\u0142aw I",
"name_en":"Prologis Park Wroc\u0142aw I",
"completearea":"167 000",
"completeareaunit":"m2",
"workingarea":"",
"workingareaunit":"m2",
"id_type":"3",
"id":"135",
"lon":16.939201369628,
"lat":51.037378299619,
"images":["public\/upload\/estate\/135\/1. Prologis Park Wroclaw I.jpg"]
}
],
"geometry":
{
"type":"Point",
"coordinates":[16.939201369628,51.037378299619]
},
"crs":
{
"type":"name",
"properties":{"name":"urn:ogc:def:crs:OGC:1.3:CRS84"}
}
},
{
"type":"Feature",
"properties":
[
{
"type":"colliers",
"thumb":"upload\/estate\/136\/thumb_2. Prologis Park Wroclaw III.jpg",
"name_pl":"Prologis Park Wroc\u0142aw III",
"name_en":"Prologis Park Wroclaw III",
"completearea":"129 500",
"completeareaunit":"m2",
"workingarea":"",
"workingareaunit":"m2",
"id_type":"3",
"id":"136",
"lon":16.928386702881,
"lat":51.105440250407,
"images":
[
"public\/upload\/estate\/136\/2. Prologis Park Wroclaw III.jpg"
]
}
],
"geometry":
{
"type":"Point",
"coordinates":[16.928386702881,51.105440250407]
},
"crs":
{
"type":"name",
"properties":{"name":"urn:ogc:def:crs:OGC:1.3:CRS84"}
}
},
.................... more more more...
I need to put my hands on properties in a list.
我需要把我的手放在列表中的属性上。
So it would be features -> properties -> name_en (list of objects like that)
所以这将是 features -> properties -> name_en（类似的对象列表）
I try this:
我试试这个：
JSONParser parser = new JSONParser();
Object obj = parser.parse(Json_str);
JSONObject jsonObject = (JSONObject) obj;
JSONArray jsonFeaturesArr = new JSONArray(jsonObject.getJSONArray("features"));
in order to create first Json Array, but I can't even do that. I get error: The method getJSONArray(String) is undefined for the type JSONObject
为了创建第一个 Json 数组，但我什至不能这样做。我收到错误：方法 getJSONArray(String) 未定义为 JSONObject 类型
(I have the same error for "getJSONObject"). Sth must be missing, I'm a java/android Newbie.
（我对“getJSONObject”有同样的错误）。一定是缺少某些东西，我是一个 java/android 新手。
If I solve error how do I go deeper into Json?
如果我解决了错误，我该如何更深入地了解 Json？
Thanx in advance for Help.
提前感谢帮助。
回答by ρяσ?ρ?я K
try as:
尝试如下：
JSONObject jSONObject = new JSONObject(jsonString);
String str_type=jSONObject.getString("type");
// using JSONArray
JSONArray featuresArr = jSONObject.getJSONArray("features");
for (int i=0; i<featuresArr.length; i++){
JSONObject anotherjsonObject = featuresArr.getJSONObject(i);
//access the fields of that json object
String str_type_one=anotherjsonObject.getString("type");
JSONArray featuresArr_properties = anotherjsonObject.getJSONArray("properties");
JSONObject propertiesjsonObject = featuresArr_properties.getJSONObject(0);
String str_type=propertiesjsonObject.getString("type");
String str_type=propertiesjsonObject.getString("thumb");
String str_type=propertiesjsonObject.getString("name_pl");
String str_type=propertiesjsonObject.getString("name_en");
////parse all items ...........
}
回答by meh
It doesn't look like XML, but a JSON.
它看起来不像 XML，而是一个 JSON。
You should initialize a JSONObject with that string.
您应该使用该字符串初始化 JSONObject。
JSONObject obj = new JSONObject(str);
And then to access a certain field just check if it exists, and then try to get a data from that field, for example to get the JSONArray call:
然后访问某个字段只需检查它是否存在，然后尝试从该字段获取数据，例如获取 JSONArray 调用：
if (obj.has("features")&&!obj.isNull("features")){
JSONArray array = obj.getJSONArray("");
for (int i=0; i<array.length; i++){
JSONObject anotherObject = array.getJSONObject(i);
//access the fields of that json object
}
}
回答by baron_bartek
Workable code:
可用代码：
import org.json.JSONArray;
import org.json.JSONObject;
try {
JSONObject jSONObject = new JSONObject(Json_str);
String str_type=jSONObject.getString("type");
JSONArray featuresArr = jSONObject.getJSONArray("features");
for (int i=0; i<featuresArr.length(); i++)
{
JSONObject anotherjsonObject = featuresArr.getJSONObject(i);
String str_type_one=anotherjsonObject.getString("type");
JSONArray featuresArr_properties = anotherjsonObject.getJSONArray("properties");
JSONObject propertiesjsonObject = featuresArr_properties.getJSONObject(0);
str_type=propertiesjsonObject.getString("name_pl");
}
} catch (Exception e) {
e.printStackTrace();
Log.i("Jsor parser error","Oh no!" + e);
}
