加载JSON字符串从成JSONArray在Android [英] Loading JSON from String into JSONArray on Android
问题描述
我已经遇到了一些问题，在相当一段时间试图加载一个JSON字符串转换成JSONArray。我希望一张贴在这里会帮我解决这个问题。
I've been experiencing some problems for quite some time trying to load a JSON string into a JSONArray. I was hoping a post here would help me solve the problem.
该文件位于资产文件夹，并包含类Kabelskap的对象。 JSON字符串格式化这样的节选：
The file is located in the assets folder and contain objects of the class Kabelskap. The JSON string is formatted like this excerpt:
[{"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOGÅSEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"},{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONSÅSEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KVÆFJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"},{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KVÆFJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KVÆFJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"},{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13","fabrikat":"ABB","typebetegnelse":"","spenning":"0.4","posisjon":"OK","kompNr":"1383","kommune":"1901 HARSTAD","latitude":"68.7781436806564","longitude":"16.5643438120601"},{"driftsmerking":"4085 07 02","objektnummer":"275122.0","adresse":"MATHUSET","fabrikat":"NEBB","typebetegnelse":"70","spenning":"0.23","posisjon":"OK","kompNr":"4085","kommune":"1911 KVÆFJORD","latitude":"68.7721426826508","longitude":"16.1785193494225"}]
这串被读入，然后传递到这个code段中的字符串变量：
This string is read into a String variable which is then passed on into this code segment:
try {
JSONObject jsonObj = new JSONObject(finalString);
for(int i = 0; i < json.length(); i++){
Kabelskap ks = (Kabelskap) json.get(i);
skap.put(ks.objektnummer, ks);
}
} catch (JSONException e) {
e.printStackTrace();
}
这要根据我所料，返回一个JSON数组，然后我可以遍历并铸成我的类的对象。
This should, according to what I expected, return an JSON array which I then could iterate through and cast into objects of my class.
11-30 00:31:33.568: INFO/System.out(389): {"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOG�SEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"}{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONS�SEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KV�FJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"}{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KV�FJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KV�FJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"}{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13" of type org.json.JSONObject cannot be converted to JSONArray
11-30 00:31:33.588: WARN/System.err(389): at org.json.JSON.typeMismatch(JSON.java:107)
11-30 00:31:33.588: WARN/System.err(389): at org.json.JSONArray.<init>(JSONArray.java:91)
11-30 00:31:33.588: WARN/System.err(389): at org.json.JSONArray.<init>(JSONArray.java:103)
11-30 00:31:33.588: WARN/System.err(389): at net.lovholm.kraftwerk.Kraftwerk.onCreate(Kraftwerk.java:68)
此错误消息表示，应该有与格式有问题，但检查这个我已经测试了JSON结构对一些在网上验证，它似乎是有效的。
This error message indicates that there should be a problem with the formatting, but to check this I have tested the JSON structure against some online validators and it seems to be valid.
，因为它是从日志返回的字符串似乎使用不同的编码比上述文件的UTF-8。我不知道这是否可能是问题的一部分，或者，如果这是日志主机的只是字符编码。
The String as it is returned from the log seems to use a different encoding than that of the file UTF-8. I'm not sure whether this may be a part of the problem or if this is just the character encoding of the log console.
任何建议对这个问题是非常欢迎的。
Any suggestion to this problem is very welcome.
----更新---- ----更新----更新---- ---- ----更新
---- UPDATE ---- ---- UPDATE ---- ---- UPDATE ---- ---- UPDATE ----
我现在已经更新了code与aj.esler，其中纠正了一些我在code摘录做上述错误的建议。下面是我的code较长的摘录，我仍然遇到问题与上述错误信息。看来这条线 JSONArray JSON =新JSONArray（finalString）; 导致一些恶意发生在JSONArray构造函数。通过在该字符串应该容纳的API与有效的JSON语法开放方括号的要求。
I have now updated the code with the suggestions from aj.esler, which corrects some of the mistakes I did in the code excerpt above. Here is a longer excerpt from my code, and I still experience problem with the error message above. It seems this line JSONArray json = new JSONArray(finalString); causes something malicious to happen in the JSONArray constructor. The String passed in should accomodate the requirements of the API with valid JSON syntax and opening square brackets.
try {
AssetManager assetManager = getAssets();
fis = assetManager.open(sourcePath);
BufferedReader bw = new BufferedReader(new InputStreamReader(fis, "utf8"));
while ((str = bw.readLine()) != null){
finalString += str;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println(finalString);
try {
JSONArray json = new JSONArray(finalString);
for(int i = 0; i < json.length(); i++){
JSONObject jsonObj = json.getJSONObject(i);
try {
Kabelskap ks = getKabelskapFromJSON(jsonObj);
skap.put(ks.objektnummer, ks);
} catch (JSONException e) {
e.printStackTrace();
}
}
} catch (JSONException e) {
e.printStackTrace();
}
-----更新2.0 --------
----- UPDATE 2.0 --------
本的System.out.println（finalString）>不知道读者或的System.out.println（）是否跳过的文字长的部分。我想$该DDMS LogCat中正在使用的字符集不支持挪威特殊字母p $ psume。
The System.out.println(finalString) > Not sure whether the reader or the System.out.println() skips long parts of the text. I would presume that the DDMS LogCat is using a charset not supporting Norwegian special letters.
11-30 11:02:27.888: INFO/System.out(4304): {"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOG�SEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"}{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONS�SEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KV�FJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"}{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KV�FJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KV�FJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"}{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13","fabrikat":"ABB","typebetegnelse":"","spenning":"0.4","posisjon":"OK","kompNr":"1383","kommune":"1901 HARSTAD","latitude":"68.7781436806564","longitude":"16.5643438120601"}{"driftsmerking":"4085 07 02","objektnummer":"275122.0","adresse":"MATHUSET","fabrikat":"NEBB","typebetegnelse":"70","spenning":"0.23","posisjon":"OK","kompNr":"4085","kommune":"1911 KV�FJORD","latitude":"68.7721426826508","longitude":"16.1785193494225"}{"driftsmerking":"3410 05 12","objektnummer":"35184.0","adresse":"HANS EGEDESGT. 20 (ERIKSGATE)","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3410","kommune":"1901 HARSTAD","latitude":"68.7980203542316","longitude":"16.538182961594"}{"driftsmerking":"0800 06 10","objektnummer":"266928.0","adresse":"GAMNES V/MAGNE HARALD OLSEN","fabrikat":"ABB","typebetegnelse":"KO35","spenning":"0.23","posisjon":"OK","kompNr":"","kommune":"1901 HARSTAD","latitude":"68.8206299498345","longitude":"16.4915959572276"}{"driftsmerking":"2580 02 02","objektnummer":"186379.0","adresse":"RESSAN","fabrikat":"ELMEK","typebetegnelse":"50 CM","spenning":"0.23","posisjon":"OK","kompNr":"2580","kommune":"1913 SK�NLAND","latitude":"68.6729130202412","longitude":"17.127746958547"}{"driftsmerking":"1500 10 06","objektnummer":"193875.0","adresse":"TUVSLETTVN. 9","fabrikat":"ABB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1500","kommune":"1901 HARSTAD","latitude":"68.74741783798","longitude":"16.5517037722856"}{"driftsmerking":"3282 02 02","objektnummer":"35547.0","adresse":"TEGEB�RVN. 12B","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3282","kommune":"1901 HARSTAD","latitude":"68.7991934883357","longitude":"16.5033927383319"}{"driftsmerking":"1430 05 02","objektnummer":"116375.0","adresse":"�VERLAND 2","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"1430","kommune":"1901 HARSTAD","latitude":"68.7759663213591","longitude":"16.5611455110691"}{"driftsmerking":"4150 05 06","objektnummer":"275496.0","adresse":" NYVN. 21","fabrikat":"ABB","typebetegnelse":"KO500","spenning":"0.4","posisjon":"OK","kompNr":"4150","kommune":"1911 KV�FJORD","latitude":"68.7741925557284","longitude":"16.1726621696438"}{"driftsmerking":"1486 07 02","objektnummer":"162192.0","adresse":"ROHOLTVN. 7","fabrikat":"ABB","typebetegnelse":"KO 700","spenning":"0.23","posisjon":"OK","kompNr":"1486","kommune":"1901 HARSTAD","latitude":"68.7550368601091","longitude":"16.5679658964195"}{"driftsmerking":"3025 02 06 / 3060 /","objektnummer":"35174.0","adresse":"HANS EGEDESGT. 6 (HVEDINGSGATE)","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3025","kommune":"1901 HARSTAD","latitude":"68.7994885383443","longitude":"16.5414817371666"}{"driftsmerking":"7045 03 06","objektnummer":"251410.0","adresse":"KONGSVIKDALEN","fabrikat":"","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"7045","kommune":"1852 TJELDSUND","latitude":"68.5682671357777","longitude":"16.2428412985428"}{"driftsmerking":"3010 03 02","objektnummer":"35143.0","adresse":"6.DIVISJONSGT. 10","fabrikat":"ABB","typebetegnelse":"KO500",
- 新的更新 -
-- New update --
从JSONArray（JSON字符串）完整的错误跟踪构造函数：
The full error trace from the JSONArray(String json) constructor:
12-03 15:14:44.290: WARN/System.err(412): org.json.JSONException: Value {"posisjon":"OK","spenning":"0.23","driftsmerking":"1420 10 04","adresse":"KANEBOG�SEN 4","kompNr":"1420","objektnummer":"56569.0","typebetegnelse":"KO500","longitude":"16.5598512563035","latitude":"68.7786964342854","kommune":"1901 HARSTAD","fabrikat":"NEBB"} of type org.json.JSONObject cannot be converted to JSONArray
12-03 15:14:44.290: WARN/System.err(412): at org.json.JSON.typeMismatch(JSON.java:107)
12-03 15:14:44.290: WARN/System.err(412): at org.json.JSONArray.<init>(JSONArray.java:91)
12-03 15:14:44.290: WARN/System.err(412): at org.json.JSONArray.<init>(JSONArray.java:103)
12-03 15:14:44.290: WARN/System.err(412): at net.lovholm.kraftwerk.Kraftwerk.onCreate(Kraftwerk.java:66)
12-03 15:14:44.290: WARN/System.err(412): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
12-03 15:14:44.290: WARN/System.err(412): at android.os.Handler.dispatchMessage(Handler.java:99)
12-03 15:14:44.290: WARN/System.err(412): at android.os.Looper.loop(Looper.java:130)
12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.main(ActivityThread.java:3683)
12-03 15:14:44.290: WARN/System.err(412): at java.lang.reflect.Method.invokeNative(Native Method)
12-03 15:14:44.290: WARN/System.err(412): at java.lang.reflect.Method.invoke(Method.java:507)
12-03 15:14:44.290: WARN/System.err(412): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-03 15:14:44.290: WARN/System.err(412): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-03 15:14:44.290: WARN/System.err(412): at dalvik.system.NativeStart.main(Native Method)
在JSONArray初始化的实施和getKabelskapfromJSON方式：
The implementation of the JSONArray initialisation and the getKabelskapfromJSON method:
-
JSON数组初始化摘录
JSON Array initialisation excerpt
尝试{ JSONArray JSON =新JSONArray（finalString）;
try { JSONArray json = new JSONArray(finalString);
for(int i = 0; i < json.length(); i++){
JSONObject jsonObj = json.getJSONObject(i);
try {
Kabelskap ks = getKabelskapFromJSON(jsonObj);
skap.put(ks.objektnummer, ks);
} catch (JSONException e) {
e.printStackTrace();
}
}
}赶上（JSONException E）{ e.printStackTrace（）; }
} catch (JSONException e) { e.printStackTrace(); }
getKabelselskapFromJSON方式：
getKabelselskapFromJSON method:
私人Kabelskap getKabelskapFromJSON（JSONObject的jsonObj）抛出JSONException {
private Kabelskap getKabelskapFromJSON(JSONObject jsonObj) throws JSONException {
String driftsmerking = jsonObj.getString("driftsmerking");
String adresse = jsonObj.getString("addresse");
String objektnummer = jsonObj.getString("objektnummer");
String spenning = jsonObj.getString("spenning");
String fabrikat = jsonObj.getString("fabrikat");
String typebetegnelse = jsonObj.getString("typebetegnelse");
String posisjon = jsonObj.getString("posisjon");
String kompNr = jsonObj.getString("kompNr");
String kommune = jsonObj.getString("kommune");
String latitude = jsonObj.getString("latitude");
String longitude = jsonObj.getString("longitude");
Kabelskap k = new Kabelskap(driftsmerking, objektnummer, adresse, fabrikat, typebetegnelse, spenning, posisjon, kompNr, kommune, latitude, longitude);
return k;
}
推荐答案
几个问题，我可以看到：
A few problems I can see:
- 您在第一行，这是一个使用的JSONObject jsonObj。然后在for循环中，您使用名为JSON不同的对象。我会认为这两个是同一个对象。另外，有资料从这个例子里缺。
- 的JSONObject没有一个方法来获得，它接受一个整数。有一个需要一个字符串，所以我会假设你的意思是那一个。
- JSONObject.get返回对应你给它的关键数据。它返回一个对象。
您收到此错误是因为你想投的JSONObject的一个Kabelskap。
The error you are getting is because you are trying to cast an JSONObject to a Kabelskap.
我会做的就是创建一个像下面的一个辅助方法。或者，您可以创建Kabelstap对象上一个特殊的构造。
What I would do is create a helper method like below. Alternatively, you could create a special constructor on the Kabelstap object.
public Kabelskap getKabelskapFromJSON(JSONObject jsonObj)
{
Kabelskap k = new Kabelskap();
String driftsmerking = jsonObj.getString("driftsmerking");
k.setDriftsmerking(driftsmerking);
String addresse = jsonObj.getString("addresse");
k.setAddresse(addresse);
String objektnummer = jsonObj.getString("objektnummer");
k.setObjektNummer(objektnummer);
double spenning = jsonObj.getDouble("spenning");
k.setSpenning(spenning);
// ... and so on for each property.
return k;
}
然后可以使用像这样：
which can then be used like so:
try {
JSONArray jsonArray = new JSONArray(yourJSONString);
for(int i = 0; i < jsonArray.length(); i++)
{
JSONObject jsonObj = jsonArray.getJSONObject(i);
Kabelskap k = getKabelskapFromJSON(jsonObj);
// do something with k. eg
System.out.println("Kabelskap@"+i+": "+k);
}
} catch (JSONException e) {
e.printStackTrace();
}
文档的JSONObject是这里和JSONArray是的here 。
Documentation for JSONObject is here and JSONArray is here.
这篇关于加载JSON字符串从成JSONArray在Android的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
