This is "test.json" before I run my code:
{
"example1": {
"example2": {
"example3": 30
}
}
}
When I run this code:
public static void test() throws IOException {
Path fileName = Paths.get("src/test.json");
try (BufferedReader reader = Files.newBufferedReader(fileName);
BufferedWriter writer = Files.newBufferedWriter(fileName, StandardOpenOption.WRITE)) {
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonObject value = gson.fromJson(reader, JsonObject.class);
JsonObject object1 = new JsonObject();
JsonObject object2 = new JsonObject();
value.add("example1", object1);
object1.add("example2", object2);
object2.addProperty("example4", 40);
gson.toJson(value, writer);
}
}
Then this happens to "test.json":
{
"example1": {
"example2": {
"example4": 40
}
}
}
How can I add the data from "example4" to "example2" without removing "example3"?
Related
I'm using the org.json.simple.JSONObject library to read some text and form it into JSON.
The code I have is as follows:
public class PerfMetrics {
private static String filePath = "Shell_Pricing_Metrics.json";
private static String jsoncontent;
public static void clearFileContents(String filePath) throws IOException {
File f1 = new File(filePath);
new FileWriter(f1);
}
public static void metricAsJSON(String testName, long testTime) {
Date date = new Date();
Timestamp ts = new Timestamp(date.getTime());
JSONObject obj = new JSONObject();
obj.put("testname", testName);
obj.put("Duration", testTime);
obj.put("Timestamp", ts.toString());
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(obj.toJSONString());
jsoncontent = gson.toJson(je);
JsonArray jsonArray = new JsonArray();
jsonArray.add(je);
jsoncontent = gson.toJson(jsonArray);
}
public static void writeJsonToFile() {
try {
File f1 = new File(filePath);
if (!(f1.exists())) {
f1.createNewFile();
}
FileWriter fw1 = new FileWriter(f1, true);
PrintWriter pw1 = new PrintWriter(fw1);
if (f1.exists() && f1.isFile()) {
pw1.println(jsoncontent);
pw1.flush();
pw1.close();
fw1.close();
} else {
System.out.println("Please provide a valid path to destination Json file");
}
} catch(Exception e){
e.printStackTrace();
}
}
}
Writes to a file as:
[
{
"Duration": 30,
"testname": "Upload Data click to Model Prices dropdown display time:",
"Timestamp": "2019-10-15 09:47:53.804"
}
]
I need the data as:
[
{
"testname": "Shopping dropdown display time:",
"Duration": 2156,
"Timestamp": "2019-10-10 14:29:01.945"
},
{
"testname": "Clothing dropdown display time:",
"Duration": 3567,
"Timestamp": "2019-10-10 14:30:01.534"
},
{
"testname": "Electrical dropdown display time:",
"Duration": 2098,
"Timestamp": "2019-10-10 14:33:01.532"
},
{
"testname": "Toys dropdown display time:",
"Duration": 4562,
"Timestamp": "2019-10-10 14:35:01.435"
}
]
I can get around this clunkily with my limited Java skills but wondered what is the best library / practice to support the transformation of the object strings into a Json Array?
It looks like you're using the function once per JSONObject, and writing the file each time - if that's the case then you could instead return the JSONObject from that method:
/*... obj.put(key, value); obj.put('Timestamp') ... */
return obj;
And then where you call .metricAsJSON now, append it to a JSONArray object like so:
JSONArray arr = new JSONArray();
for (... metric in some other array ...) {
JSONObject obj = GetMetrics.metricAsJSON(key, value);
arr.put(obj);
}
String jsonString = arr.toString();
/* Write jsonString to file */
If you need to add values dynamically and write multiple times, you could store the JSONArray as a method variable, or load the file into a JSONArray object each time you need to append something to the end.
You need to do this
public class GetMetrics {
public static void clearFileContents(String filePath) throws IOException {
File f1 = new File(filePath);
new FileWriter(f1);
}
public static void metricAsJSON(String key, long value, String filePath) {
Date date = new Date();
Timestamp ts = new Timestamp(date.getTime());
JSONObject obj = new JSONObject();
obj.put(key, value);
obj.put("Timestamp", ts.toString());
try {
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(obj.toJSONString());
String jsoncontent = = gson.toJson(je);
File f1 = new File(filePath);
if (!(f1.exists())) {
f1.createNewFile();
}
FileWriter fw1 = new FileWriter(f1, true);
PrintWriter pw1 = new PrintWriter(fw1);
if (f1.exists() && f1.isFile()) {
pw1.println(jsoncontent);
pw1.flush();
pw1.close();
fw1.close();
} else {
System.out.println("Please provide a valid path to destination Jsonfile");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
Here is code of my getStream method:
public static Twitch_Stream getStream(String channelname) {
try {
String json = API.readJsonFromUrl("https://api.twitch.tv/kraken/streams?channel=" + channelname);
Twitch_Stream stream = new Twitch_Stream();
if (json.equalsIgnoreCase("[]")) {
stream.setOnline(false);
return stream;
}
JsonArray jb = gson.fromJson(json, JsonArray.class);
if (jb.size() != 0) {
JsonObject jo = (JsonObject) jb.get(0);
stream.setOnline(true);
stream.load(jo);
}
return stream;
} catch (Exception error) {
error.printStackTrace();
}
return null;
}
and here is code of Twitch_Stream class http://pastebin.com/3RX1L1cv
When I make something like this
Twitch_Stream streamer = Twitch_API.getStream("Jankos");
Bukkit.broadcastMessage("getName " + streamer.getName());
Bukkit.broadcastMessage(streamer.isOnline() + "");
streamer.getName() return null and streamer.isOnline() returns false, even when stream is on.
Where did I make a mistake?
I don't know what problem is in your code but simple workaround would be reading content from "https://api.twitch.tv/kraken/streams/" + channel which is JSON in format:
{
"_links" : {
//links to stream and channel
},
"stream" : {
//details about current stream
}
}
Now if value of stream key is null stream is off-line. If it is not null, it is on-line.
So your code can look like
public static void main(String[] argv) throws IOException {
System.out.println(checkIfOnline("Jankos"));
System.out.println(checkIfOnline("nightblue3"));
}
public static boolean checkIfOnline(String channel) throws IOException {
String channerUrl = "https://api.twitch.tv/kraken/streams/" + channel;
String jsonText = readFromUrl(channerUrl);// reads text from URL
JSONObject json = new JSONObject(jsonText);
return !json.isNull("stream");
}
private static String readFromUrl(String url) throws IOException {
URL page = new URL(url);
try (Stream<String> stream = new BufferedReader(new InputStreamReader(
page.openStream(), StandardCharsets.UTF_8)).lines()) {
return stream.collect(Collectors.joining(System.lineSeparator()));
}
}
I used JSONObject from org.json library. I am also using Java 8 and its streams.
If you want to use gson you can use instead something like
public static boolean checkIfOnline(String channel) throws IOException {
String channerUrl = "https://api.twitch.tv/kraken/streams/" + channel;
String jsonText = readFromUrl(channerUrl);// reads text from URL
JsonParser parser = new JsonParser();
JsonObject json = parser.parse(jsonText).getAsJsonObject();
return !json.get("stream").isJsonNull();
}
If you don't have Java 8 you can rewrite code reading text from URL to something like
private static String readFromUrl(String url) throws IOException {
URL page = new URL(url);
StringBuilder sb = new StringBuilder();
Scanner scanner = null;
try{
scanner = new Scanner(page.openStream(), StandardCharsets.UTF_8.name());
while (scanner.hasNextLine()){
sb.append(scanner.nextLine());
}
}finally{
if (scanner!=null)
scanner.close();
}
return sb.toString();
}
or from what I see you can use your API.readJsonFromUrl instead of readFromUrl.
I convert JSONObject in string for parse it in JsonNode with jackson but i have a List in my JSONObject and when i parse it with a ObjectMapper i get this :
["{Property1 : value1, Property2 : value2}"]
And i can't call myJsonNodeObject.get(i).get("Property1") this is my problem.
I have tried to cast my List in JSONArray in my JSONObject but don't work.
resultAsJSONObject = new JSONObject();
resultAsJSONObject.put("Label", getMetricStatisticsResult.getLabel());
resultAsJSONObject.put("Datapoints", getMetricStatisticsResult.getDatapoints());
resultAsJSONObject.put("fromDate", fromDate.getTimeInMillis());
resultAsJSONObject.put("toDate", toDate.getTimeInMillis());
resultAsJSONObject.put("error", "");
resultAsString = resultAsJSONObject.toString();
mapper.readValue(resultAsString, MetricsData.class);
Assuming that you have a JSON string which you just want to change. Then you can use Jackson to parse it as a ObjecNode and then modify it. Here is an example:
public class JacksonModifyJson {
static final String JSON = "{\"name\":\"Bob\", \"age\":13}";
public static void main(String[] args) throws IOException {
final ObjectMapper mapper = new ObjectMapper();
final ObjectNode jsonNode = mapper.readValue(JSON, ObjectNode.class);
jsonNode.put("url", "example.com");
System.out.println(mapper.writeValueAsString(jsonNode));
}
}
Output:
{"name":"Bob","age":13,"url":"example.com"}
THis method is really easy and works too
try {
JSONObject jsonObject = new JSONObject(THESTRINGHERE);
String[] names = JSONObject.getNames(jsonObject);
JSONArray jsonArray = jsonObject.toJSONArray(new JSONArray(names));
ArrayList<String> listdata = new ArrayList<String>();
JSONArray jArray = (JSONArray)jsonArray;
if (jArray != null) {
for (int i=0;i<jArray.length();i++){
listdata.add(jArray.get(i).toString());
}
}
// System.out.println(listdata);
} catch (Exception e) {
System.out.println(e.getMessage());
}
I would like to append JSON object to existing JSON array to get data structure like this.
"results":[
{
"lat":"value",
"lon":"value"
},
{
"lat":"value",
"lon":"value"
}
]
I'm trying to do it using the code in example, but unfortunately whole object is overriden everytime.
Log.i(AppHelper.APP_LOG_NAMESPACE, "POSITIONS AVAILABLE " + jsonDataString);
AppHelper helper = new AppHelper(ctx);
JSONObject mainObject = new JSONObject(jsonDataString);
JSONObject valuesObject = new JSONObject();
JSONArray list = new JSONArray();
//putv given values to the JSON
valuesObject.put("lat", lat.toString());
valuesObject.put("lon", lon.toString());
valuesObject.put("city", city);
valuesObject.put("street", street);
valuesObject.put("date", helper.getActualDateTime());
valuesObject.put("time", helper.getActualDateTime());
list.put(valuesObject);
//mainObject.put("values", list);
mainObject.accumulate("values", list);
saveJsonData(ctx, mainObject.toString(),"positions");
How it should be right?
Put and accumulate everytime rewrite all previous values, but i would like to append this object:
{
"lat":"value",
"lon":"value"
},
Into results parent.
BTW: I would like to do it without GSON.
Thanks for any help..
There isnt any problem with your code. It does append
String jsonDataString = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }, { \"lat\":\"value\", \"lon\":\"value\"}]}";
JSONObject mainObject = new JSONObject(jsonDataString);
JSONObject valuesObject = new JSONObject();
JSONArray list = new JSONArray();
valuesObject.put("lat", "newValue");
valuesObject.put("lon", "newValue");
valuesObject.put("city", "newValue");
valuesObject.put("street", "newValue");
valuesObject.put("date", "newValue");
valuesObject.put("time", "newValue");
list.put(valuesObject);
mainObject.accumulate("values", list);
System.out.println(mainObject);
This prints {"values":[[{"date":"newValue","city":"newValue","street":"newValue","lon":"newValue","time":"newValue","lat":"newValue"}]],"results":[{"lon":"value","lat":"value"},{"lon":"value","lat":"value"}]}.
Isnt this what you are expecting?
With gson you can do like
import com.google.gson.Gson;
import com.google.gson.JsonObject;
public class AddJson {
public static void main(String[] args) {
String json = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }, { \"lat\":\"value\", \"lon\":\"value\"}]}";
Gson gson = new Gson();
JsonObject inputObj = gson.fromJson(json, JsonObject.class);
JsonObject newObject = new JsonObject() ;
newObject.addProperty("lat", "newValue");
newObject.addProperty("lon", "newValue");
inputObj.get("results").getAsJsonArray().add(newObject);
System.out.println(inputObj);
}
}
Simple Approach
String jsonData = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }]}";
System.out.println(jsonData);
try {
JSONArray result = new JSONObject(jsonData).getJSONArray("results");
result.getJSONObject(0).put("city","Singapore");
jsonData = "{\"results\":"+result.toString()+"}";
System.out.println(jsonData);
} catch (JSONException e) {
e.printStackTrace();
}
OutPut Before Appending
{"results":[{"lat":"value","lon":"value" }]}
OutPut After Appending
{"results":[{"lon":"value","lat":"value","city":"Singapore"}]}
If you want to add new value to an Object you can try the below as well
Before:
{
"Name": "EnCoMa",
"Manager": "Abhishek Kasetty"
}
code :
JsonFactory factory = new JsonFactory();
ObjectMapper mapper = new ObjectMapper(factory);
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = ow.writeValueAsString(TheObjectToWhichYouWantToAddNewValue);
ObjectNode node = (ObjectNode) mapper.readTree(json);
node.putPOJO("new Key","new value")
after:
{
"Name": "EnCoMa",
"Manager": "Abhishek Kasetty",
"new Key": "new value"
}
I am trying to write an automated Java test where the code will go to a specified URL, read the JSON data and print it up.
Here is the JSON I am trying to access;
{
"status": "success",
"records": [
{
"timestamp": 1381222871868,
"deviceId": "288",
"temperature": 17
},
{
"timestamp": 1381222901868,
"deviceId": "288",
"temperature": 17
},
{
"timestamp": 1381222931868,
"deviceId": "288",
"temperature": 17
},
]}
As you can see I only have 3 elements, Timestamp, DeviceId and Temperature.
What I am ultimately aiming for it to be able to get 2 Timestamp values and take one value away from the other, if that is possible.
Anyway I have been trying to do this all day and am having no luck whatsoever. I was recommended to use Gson and I have included the jar files into my classpath.
If anyone knows anything or can help me in any way it would be much appreciated as I have exhausted Google and myself trying to work this out.
Here is the code I have to display the full list, but I do not fully understand it and so far can't manipulate it to my advantage;
public static void main(String[] args) throws Exception
{
String jsonString = callURL("http://localhost:8000/eem/api/v1/metrics/temperature/288");
System.out.println("\n\njsonString: " + jsonString);
// Replace this try catch block for all below subsequent examples
/*try
{
JSONArray jsonArray = new JSONArray(jsonString);
System.out.println("\n\njsonArray: " + jsonArray);
}
catch (JSONException e)
{
e.printStackTrace();
}*/
try
{
JSONArray jsonArray = new JSONArray(jsonString);
int count = jsonArray.length(); // get totalCount of all jsonObjects
for(int i=0 ; i< count; i++)
{ // iterate through jsonArray
JSONObject jsonObject = jsonArray.getJSONObject(i); // get jsonObject # i position
System.out.println("jsonObject " + i + ": " + jsonObject);
}
}
catch (JSONException e)
{
e.printStackTrace();
}
}
public static String callURL(String myURL)
{
//System.out.println("Requested URL:" + myURL);
StringBuilder sb = new StringBuilder();
URLConnection urlConn = null;
InputStreamReader in = null;
try
{
URL url = new URL(myURL);
urlConn = url.openConnection();
if (urlConn != null)
{
urlConn.setReadTimeout(60 * 1000);
}
if (urlConn != null && urlConn.getInputStream() != null)
{
in = new InputStreamReader(urlConn.getInputStream(),
Charset.defaultCharset());
BufferedReader bufferedReader = new BufferedReader(in);
if (bufferedReader != null)
{
int cp;
while ((cp = bufferedReader.read()) != -1)
{
sb.append((char) cp);
}
bufferedReader.close();
}
}
in.close();
}
catch (Exception e)
{
throw new RuntimeException("Exception while calling URL:"+ myURL, e);
}
return sb.toString();
}
Cheers
I had read the values from file but you can read from URL, the extracting process code is present inside extractJson() method.
public static void main(String [] args)
{
try
{
FileInputStream fis=new FileInputStream("testjson.json");
int b=0;
String val="";
while((b=fis.read())!=-1)
{
val=val+(char)b;
}
extractJson(val);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void extractJson(String json)
{
try
{
JSONObject jobject=new JSONObject(json);
System.out.println("Json object Length: "+jobject.length());
System.out.println("Status: "+jobject.getString("status"));
JSONArray jarray=new JSONArray(jobject.getString("records"));
System.out.println("Json array Length: "+jarray.length());
for(int j=0;j<jarray.length();j++)
{
JSONObject tempObject=jarray.getJSONObject(j);
System.out.println("Timestamp: "+tempObject.getString("timestamp"));
System.out.println("Device Id: "+tempObject.getString("deviceId"));
System.out.println("Temperature: "+tempObject.getString("temperature"));
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
You could use ArrayList to store the values which will be available inside for loop. From your question you need to pass jsonString this variable to the extractJson() method. Use org.json jar file to process json. If you could alter this for gson then it'll be good for your requirement.
here's how to do it via Google-Gson
class MyRecord
{
private long timestamp;
private String deviceId;
private Integer temperature;
//Getters & setters
}
public static void main(String... args){
String myJsonString=callUrl("http://mydomain.com/x.json");
JsonParser jp = new JsonParser();
JsonElement ele = jp.parse(myJsonString);
Gson gg = new Gson();
Type type = new TypeToken<List<MyRecord>>() {
}.getType();
List<MyRecord> lst= gg.fromJson(ele.getAsJsonObject().get("records"), type);
//Now the json is parsed in a List of MyRecord, do whatever you want to with it
}
An "high-level" Gson parsing answer:
package stackoverflow.questions.q19252374;
import java.util.List;
import com.google.gson.Gson;
public class Q19252374 {
class Record {
Long timestamp;
String deviceId;
Long temperature;
}
class Container {
List<Record> records;
}
public static void main(String[] args) {
String json = "{ \"status\": \"success\", \"records\": [{\"timestamp\": 1381222871868,\"deviceId\": \"288\",\"temperature\": 17 },{\"timestamp\": 1381222901868,\"deviceId\": \"288\",\"temperature\": 17 },{\"timestamp\": 1381222931868,\"deviceId\": \"288\",\"temperature\": 17 } ]} ";
Gson g = new Gson();
Container c = g.fromJson(json, Container.class);
for (Record r : c.records)
System.out.println(r.timestamp);
}
}
Of course this is the result:
1381222871868
1381222901868
1381222931868