I am using json simple
this is my code:
public static String getDetails() {
String name = System.getProperty("user.name");
JSONParser parser = new JSONParser();
File dir = new File("C:\\Users\\" + name + "\\AppData\\Roaming\\.minecraft\\launcher_profiles.json");
if (dir.exists()) {
Object obj = null;
try {
obj = parser.parse(new FileReader("C:\\Users\\" + name + "\\AppData\\Roaming\\.minecraft\\launcher_profiles.json"));
} catch (Exception e) {
e.printStackTrace();
}
JSONObject jsonObject = (JSONObject) obj;
String da = (String) jsonObject.get("username");
try {
return obj.toString() + "\n" + da;
} catch (Exception e) {
e.printStackTrace();
}
} else {
System.out.println("dir no exist");
}
return null;
}
when i print this out it returns all the text in the json file and it returns null from String 'da' I dont know why because its not null it exist in the file??
JSON file: https://hastebin.com/sirefacado.json
To access the username you have to use the fully qualified path. In your case that is:
String da = (String) ((JSONObject)((JSONObject)jsonObject.get("authenticationDatabase")).get("d46e53840f3f41a2b9e44e2d4d72ebeb")).get("username");
That is, because your username is encapsulated in the following part of the JSON file:
authenticationDatabase: {
d46e53840f3f41a2b9e44e2d4d72ebeb: {
accessToken: "86ccdfsdfsdfsc2c38ec6012a1ccfsdfR",
username: "privater#email.co",
profiles: {
ad4fa7102fb7432cb4e07d471e348c77: {
displayName: "hio"
}
}
}
}
To access the username via the token you have to go via the authenticationDatabase. It may be the case that there are multiple ids, therefore you have to iterate over all the existing ones
For that you can do
JSONObject authDatabase = (JSONObject) jsonObject.get("authenticationDatabase");
for(Object id : authDatabase.keySet()) {
JSONObject authEntry = (JSONObject) authDatabase.get(id);
String username = (String) authDatabase.get("username");
/* now do something with the username.
You can abort after you found the first username
and store it in the da object, or create a list
of existing usernames, ... */
}
Following are the top level keys in the JSON you posted.
{
"settings": {...some data...},
"launcherVersion": {...some data...},
"clientToken": "dbf69db062d5d32b093e7d67ce744d60",
"profiles": {...some data...},
"analyticsFailcount": 0,
"analyticsToken": "f18d7c0f152f5ad44b2a6525e0d5cfa9",
"selectedProfile": "OptiFine",
"authenticationDatabase": {...some data...},
"selectedUser": {...some data...}
}
Your code tries to extract the value of username from the top level.
String da = (String) jsonObject.get("username")
It doesn't contain the key username. Hence, it is print null.
Your statement below is trying to fetch an element named "username" from the root JSON object however, your actual value is nested inside.
String da = (String) jsonObject.get("username");
{
"authenticationDatabase": {
"d46e53840f3f41a2b9e44e2d4d72ebeb": {
"accessToken": "86ccdfsdfsdfsc2c38ec6012a1ccfsdfR",
"username": "privater#email.co",
"profiles": {
"ad4fa7102fb7432cb4e07d471e348c77": {
"displayName": "hio"
}
}
}
}
}
In order to fetch inner element, you need to drill down as follows. Understand that it is not an good idea to hard cord the key inside the "authenticationDatabase" object.
JSONObject jsonObject = (JSONObject) obj;
String da;
try {
JSONObject adb = (JSONObject) jsonObject.get("authenticationDatabase");
JSONObject adbKey = null;
for(Object key:adb.keySet()) {
String sKey = (String) key;
adbKey = (JSONObject) adb.get(sKey);
da = (String) adbKey.get("username");
return obj.toString() + "\n" + da;
}
} catch (Exception e) {
e.printStackTrace();
}
Related
I am trying to parse a json file in java. However I keep receiving an error.
This is the file I am trying to parse:
[{
"name": "John Smith",
"totalSales": 250,
"salesPeriod": 10,
"experienceMultiplier": 0.5
},
{
"name": "David Prowless",
"totalSales": 250,
"salesPeriod": 10,
"experienceMultiplier": 0.5
}
]
This is what I have tried:
public static void main(String[] args)
{
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("data.json"));
JSONObject jsonObject = (JSONObject) obj;
String name = (String) jsonObject.get("name");
System.out.println(name);
String totalSales = (String) jsonObject.get("totalSales");
System.out.println(totalSales);
String salesPeriod = (String) jsonObject.get("salesPeriod");
System.out.println(salesPeriod);
String exp = (String) jsonObject.get("exp");
System.out.println(exp);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
This is the error I receive:
Exception in thread "main" java.lang.ClassCastException: org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject
at mentormate.json.MentormateJson.main(MentormateJson.java:23)
Java Result: 1
I apologize if this is a silly question with a simple solution. I am new to json.
EDIT:
I have decided to go along with the code below. However, I cannot set the for each loop right to iterate through object in the json file.
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("data.json"));
JSONArray jsonObjects = (JSONArray) obj;
for ( JSONObject jsonObject : jsonObjects) {
String name = (String) jsonObject.get("name");
System.out.println(name);
String totalSales = (String) jsonObject.get("totalSales");
System.out.println(totalSales);
String salesPeriod = (String) jsonObject.get("salesPeriod");
System.out.println(salesPeriod);
String exp = (String) jsonObject.get("exp");
System.out.println(exp);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
FINAL EDIT (PROBLEM SOLVED):
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("data.json"));
JSONArray jsonObjects = (JSONArray) obj;
for (Object o : jsonObjects) {
JSONObject jsonObject = (JSONObject) o;
String name = (String) jsonObject.get("name");
System.out.println(name);
Long totalSales = (Long) jsonObject.get("totalSales");
System.out.println(totalSales);
Long salesPeriod = (Long) jsonObject.get("salesPeriod");
System.out.println(salesPeriod);
Double exp = (Double) jsonObject.get("experienceMultiplier");
System.out.println(exp);
System.out.println();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
Please try this:
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("data.json"));
JSONArray jsonObjects = (JSONArray) obj;
for (Object o : jsonObjects) {
JSONObject jsonObject = (JSONObject) o;
String name = (String) jsonObject.get("name");
System.out.println(name);
Long totalSales = (Long)jsonObject.get("totalSales");
System.out.println(totalSales);
String salesPeriod = (String) jsonObject.get("salesPeriod");
System.out.println(salesPeriod);
String exp = (String) jsonObject.get("exp");
System.out.println(exp);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
Your data contains a JSON array, not a JSON object.
Change the line
JSONObject jsonObject = (JSONObject) obj;
to
JSONArray jsonArray = (JSONArray) obj;
This array will contain two JSONObjects.
you can use alibaba's fastjson.You can download fastjson jar file,this is pom xml:
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.56</version>
</dependency>
when you import this jar，you can code like this:
import com.alibaba.fastjson.JSONObject;
import java.util.List;
public class MainTest {
public static void main(String[] args) {
String json = "[\n" +
"{\n" +
"\"name\": \"John Smith\",\n" +
"\"totalSales\": 250,\n" +
"\"salesPeriod\": 10,\n" +
"\"experienceMultiplier\": 0.5\n" +
"},\n" +
"{\n" +
"\"name\": \"David Prowless\",\n" +
"\"totalSales\": 250,\n" +
"\"salesPeriod\": 10,\n" +
"\"experienceMultiplier\": 0.5\n" +
"}\n" +
"]";
List<JSONObject> jsonObjects = JSONObject.parseArray(json,JSONObject.class);
jsonObjects.stream().forEach(System.out::print);
}
}
Please find whole example below.
1) Create DTO class with your params like,
class JsonParam {
private String name;
private int totalSales;
private int salesPeriod;
private float experienceMultiplier;
//Getter and setters
}
2) Then add Gson jar with min. version (2.2.4) - get online, or add dependency for maven structure.
3) Finally, add 2 lines in your code to get any parameter like,
List<JsonParam> jsonParams = new Gson().fromJson(json, new TypeToken<List<JsonParam>>() {}.getType());
System.out.println(jsonParams.get(0).getName());
In above statement, I have used 0 index, you can use for-loop as per your requirement.
try {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("./test.json"));
// parsing the JSON string inside the file that we created earlier.
JSONArray jsonarray = (JSONArray) obj;
for (int i = 0; i < jsonarray.size(); i++) {
JSONObject jsonObject = (JSONObject) jsonarray.get(i);
String name = (String) jsonObject.get("name");
System.out.println(name);
long totalSales = (long) jsonObject.get("totalSales");
System.out.println(totalSales);
long salesPeriod = (long) jsonObject.get("salesPeriod");
System.out.println(salesPeriod);
Double exp = (Double) jsonObject.get("experienceMultiplier");
System.out.println(exp);
}
} catch (Exception e) {
e.printStackTrace();
}
Try this one
I currently received the json file in java, turned the json file on the formun, debugged it, and tried sysout.
The problem is, I try to output to the table in jsp, but only the last source from json comes out.
How can we solve this?
#RequestMapping(value = "spaghettiSub", method = RequestMethod.POST)
public String spaghetti(ModelMap modelMap) {
JSONParser jsonParser = new JSONParser();
try{
JSONArray page = (JSONArray) jsonParser.parse(new FileReader("d:\\spaghetti.json"));
int pageCnt = page.size();
Map<String,String> map = new HashMap<String,String>();
List<Map<String,String>> spaghettiList = new ArrayList<Map<String,String>>();
for(int i = 0; i < pageCnt; i++) {
Object obj = page.get(i);
JSONObject jsonObject = (JSONObject) obj;
String no = (String) jsonObject.get("no");
String name = (String) jsonObject.get("name");
String explanation= (String) jsonObject.get("explanation");
map.put("no", no);
map.put("name", name);
map.put("explanation", explanation);
spaghettiList.add(map);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
return "sub/" + this.urlbase + "/spaghetti";
}
json
[
{
"no": "1",
"name": "Spaghettoni",
"explanation": "It is commonly used in the Carbonara Spaghetti, which is about 2mm thick."
},
{
"no": "2",
"name": "Spaghettini",
"explanation": "Spaghetti 1.6mm thick"
},
{
"no": "3",
"name": "Fedelini",
"explanation": "Spaghetti from 1.3mm to 1.5mm thick"
}]
you have to move this Map<String,String> map = new HashMap<String,String>(); inside your for loop.
Note:
As JB Nizet mentioned start using objects instead of JsonArray.
First thing first
Solve Issue
You are only getting last row in your JSP is because you have declared your Map outside of for loop.
If you are in hurry and have no time in world just move this
Map<String,String> map = new HashMap<String,String>();
inside
for(int i = 0; i < pageCnt; i++) {
This will solve your problem.
Improve your Code
But you can make it way more better and efficient by doing something like this
Define a DTO class
public class MyData {
private String no;
private String name;
private String explanation;
// getter setter
}
Use this DTO class to fill values like you did for Map
The whole code looks something like this.
#RequestMapping(value = "spaghettiSub", method = RequestMethod.POST)
public String spaghetti(ModelMap modelMap) {
JSONParser jsonParser = new JSONParser();
try{
JSONArray page = (JSONArray) jsonParser.parse(new FileReader("d:\\spaghetti.json"));
int pageCnt = page.size();
List<MyData> spaghettiList = new ArrayList<MyData>();
for(int i = 0; i < pageCnt; i++) {
MyData mydata = new MyData();
Object obj = page.get(i);
JSONObject jsonObject = (JSONObject) obj;
String no = (String) jsonObject.get("no");
String name = (String) jsonObject.get("name");
String explanation= (String) jsonObject.get("explanation");
mydata.setNo(no);
mydata.setName(name);
mydata.setExplanation(explanation);
spaghettiList.add(mydata);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
return "sub/" + this.urlbase + "/spaghetti";
}
I am trying to perform a GET request to https://www.cryptocompare.com/api/data/coinlist/, I am grabbing the values "ImageUrl, "Name", and "CoinName". However, I am only receiving about ~230 values with an "ImageUrl". I should be receiving ~1470. This is the exception I receive. I am confused by this since I do a GET request using Postman and it has a value for every "ImageUrl".
org.json.JSONException: No value for ImageUrl
Here is the code for my GET request
#Override
public void GETCoins() {
String url = "https://www.cryptocompare.com/api/data/coinlist/";
Log.d("Debug ", "URL: " + url);
//Run async task to pull weather data. weatherTask.get... forces main thread to wait for this to finish
HTTPAsyncTask coinTask = new HTTPAsyncTask(this);
coinTask.execute(url, "GET");
try {
JSONObject jsonObject = new JSONObject(coinTask.get());
JSONObject obj = new JSONObject(jsonObject.getString("Data"));
Iterator<?> keys = obj.keys();
int i = 0;
while(keys.hasNext() ) {
String key = (String) keys.next();
if(obj.get(key) instanceof JSONObject) {
JSONObject val = new JSONObject(obj.get(key).toString());
String imageUrl = baseImageUrl + val.getString("ImageUrl");
String name = val.getString("Name");
String currency = val.getString("CoinName");
CryptoData data = new CryptoData(i, currency, 0,0, imageUrl, name);
allCurrencyList.add(data);
i++;
}
}
//updateData(jsonObject);
} catch (InterruptedException | JSONException | ExecutionException e) {
e.printStackTrace();
} finally {
Log.d("Debug ", "Coin API is null");
}
}
Once i have parsed a JSON String into a GSON provided JsonObject class, (assume that i do not wish to parse it into any meaningful data objects, but strictly want to use JsonObject), how am i able to modify a field / value of a key directly?
I don't see an API that may help me.
https://static.javadoc.io/com.google.code.gson/gson/2.6.2/com/google/gson/JsonObject.html
Strangely, the answer is to keep adding back the property. I was half expecting a setter method. :S
System.out.println("Before: " + obj.get("DebugLogId")); // original "02352"
obj.addProperty("DebugLogId", "YYY");
System.out.println("After: " + obj.get("DebugLogId")); // now "YYY"
This works for modifying childkey value using JSONObject.
import used is
import org.json.JSONObject;
ex json:(convert json file to string while giving as input)
{
"parentkey1": "name",
"parentkey2": {
"childkey": "test"
},
}
Code
JSONObject jObject = new JSONObject(String jsoninputfileasstring);
jObject.getJSONObject("parentkey2").put("childkey","data1");
System.out.println(jObject);
output:
{
"parentkey1": "name",
"parentkey2": {
"childkey": "data1"
},
}
Since 2.3 version of Gson library the JsonArray class have a 'set' method.
Here's an simple example:
JsonArray array = new JsonArray();
array.add(new JsonPrimitive("Red"));
array.add(new JsonPrimitive("Green"));
array.add(new JsonPrimitive("Blue"));
array.remove(2);
array.set(0, new JsonPrimitive("Yelow"));
Another approach would be to deserialize into a java.util.Map, and then just modify the Java Map as wanted. This separates the Java-side data handling from the data transport mechanism (JSON), which is how I prefer to organize my code: using JSON for data transport, not as a replacement data structure.
It's actually all in the documentation.
JSONObject and JSONArray can both be used to replace the standard data structure.
To implement a setter simply call a remove(String name) before a put(String name, Object value).
Here's an simple example:
public class BasicDB {
private JSONObject jData = new JSONObject;
public BasicDB(String username, String tagline) {
try {
jData.put("username", username);
jData.put("tagline" , tagline);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public String getUsername () {
String ret = null;
try {
ret = jData.getString("username");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return ret;
}
public void setUsername (String username) {
try {
jData.remove("username");
jData.put("username" , username);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public String getTagline () {
String ret = null;
try {
ret = jData.getString("tagline");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return ret;
}
public static JSONObject convertFileToJSON(String fileName, String username, List<String> list)
throws FileNotFoundException, IOException, org.json.simple.parser.ParseException {
JSONObject json = new JSONObject();
String jsonStr = new String(Files.readAllBytes(Paths.get(fileName)));
json = new JSONObject(jsonStr);
System.out.println(json);
JSONArray jsonArray = json.getJSONArray("users");
JSONArray finalJsonArray = new JSONArray();
/**
* Get User form setNewUser method
*/
//finalJsonArray.put(setNewUserPreference());
boolean has = true;
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
finalJsonArray.put(jsonObject);
String username2 = jsonObject.getString("userName");
if (username2.equals(username)) {
has = true;
}
System.out.println("user name are :" + username2);
JSONObject jsonObject2 = jsonObject.getJSONObject("languages");
String eng = jsonObject2.getString("Eng");
String fin = jsonObject2.getString("Fin");
String ger = jsonObject2.getString("Ger");
jsonObject2.put("Eng", "ChangeEnglishValueCheckForLongValue");
System.out.println(" Eng : " + eng + " Fin " + fin + " ger : " + ger);
}
System.out.println("Final JSON Array \n" + json);
jsonArray.put(setNewUserPreference());
return json;
}
I am trying to put String[] in jsonObject and getting following error
java.lang.IllegalArgumentException: Invalid type of value. Type:
[[Ljava.lang.String;] with value: [[Ljava.lang.String;#189db56] at
com.ibm.json.java.JSONObject.put(JSONObject.java:241)
Please help me to resolve this.
Thanks
public JSONObject toJSONObject() {
JSONObject jsonObject = new JSONObject();
//Use reflection to get a list of all get methods
//and add there corresponding values to the JSON object
Class cl = dto.getClass();
logger.infoFormat("Converting {0} to JSON Object", cl.getName());
Method[] methods = cl.getDeclaredMethods();
for (Method method : methods) {
String methodName = method.getName();
if (methodName.startsWith("get")) {
logger.infoFormat("Processing method - {0}", methodName);
//Check for no parameters
if (method.getParameterTypes().length == 0) {
String tag = getLabel(method);
Object tagValue = new Object();
try {
tagValue = method.invoke(dto);
} catch (Exception e) {
logger.errorFormat("Error invoking method - {0}", method.getName());
}
if (method.getReturnType().isAssignableFrom(BaseDTO.class)) {
DTOSerializer serializer = new DTOSerializer((BaseDTO) tagValue);
jsonObject.put(tag, serializer.toJSONObject());
} else if (method.getReturnType().isAssignableFrom(List.class)) {
ListSerializer serializer = new ListSerializer((List<BaseDTO>) tagValue);
jsonObject.put(tag, serializer.toJSONArray());
} else {
if (tagValue != null) jsonObject.put(tag, tagValue);
}
}
}
}
return(jsonObject);
}
try
jsonObject.put("yourKey", Arrays.asList(yorStringArray));
As you should read the manual first http://www.json.org/javadoc/org/json/JSONObject.html there is no variation of it expects an Object[]
Maybe you should take a look at google-gson.
I like it very much to work with json in Java.