Kr1
Reputation: 1303
How to return a JSONObject instead HashMap with ResponseEntity? (No converter found for return value of type: class org.json.JSONObject)
I am able to return an HashMap as a JSON from my REST API built on Spring Boot. Here my Method:
@ResponseBody
@Transactional
@GetMapping("create_coinmarketcap_snapshot")
public ResponseEntity<HashMap> create_coinmarketcap_snapshot() {
String jsonString = callURL("https://api.coinmarketcap.com/v2/ticker/?limit=5");
JSONArray coinmarketcapsnapshotsArray = new JSONArray();
JSONObject coinmarketcapsnapshotsJSONObject = new JSONObject();
HashMap<Integer, CoinmarketcapSnapshot> coinmarketcapsnapshotsHashMap = new HashMap<>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONObject jsonObjectData = jsonObject.getJSONObject("data");
Iterator<?> keys = jsonObjectData.keys();
int count = 0;
while (keys.hasNext()) {
count++;
String key = (String) keys.next();
if (jsonObjectData.get(key) instanceof JSONObject) {
JSONObject jsonObjectDataCrypto = jsonObjectData.getJSONObject(key);
JSONObject jsonObjectDataCryptoQuotes = jsonObjectDataCrypto.getJSONObject("quotes").getJSONObject("USD");
CoinmarketcapSnapshot coinmarketcapsnapshotObject = new CoinmarketcapSnapshot();
String dateFormatted = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss").format(Calendar.getInstance().getTime());
coinmarketcapsnapshotObject.setTitle(jsonObjectDataCrypto.get("name") + " - " + dateFormatted);
coinmarketcapsnapshotObject.setCryptocurrencyId((int) jsonObjectDataCrypto.get("id"));
if(jsonObjectDataCrypto.get("rank")!=null){
coinmarketcapsnapshotObject.setRank((int) jsonObjectDataCrypto.get("rank"));
}
if(jsonObjectDataCrypto.get("circulating_supply")!=null){
coinmarketcapsnapshotObject.setCirculatingSupply((Double) jsonObjectDataCrypto.get("circulating_supply"));
}
if(jsonObjectDataCrypto.get("total_supply")!=null){
coinmarketcapsnapshotObject.setTotalSupply((Double) jsonObjectDataCrypto.get("total_supply"));
}
if(!jsonObjectDataCrypto.isNull("circulating_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("circulating_supply"));
}
if(!jsonObjectDataCrypto.isNull("total_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("total_supply"));
}
if(!jsonObjectDataCrypto.isNull("max_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("max_supply"));
}
if(!jsonObjectDataCryptoQuotes.isNull("price")) {
coinmarketcapsnapshotObject.setPrice((Double) jsonObjectDataCryptoQuotes.get("price"));
}
if(!jsonObjectDataCryptoQuotes.isNull("volume_24h")) {
coinmarketcapsnapshotObject.setVolume24h((Double) jsonObjectDataCryptoQuotes.get("volume_24h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("market_cap")) {
coinmarketcapsnapshotObject.setMarketCap((Double) jsonObjectDataCryptoQuotes.get("market_cap"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_1h")) {
coinmarketcapsnapshotObject.setPercentChange1h((Double) jsonObjectDataCryptoQuotes.get("percent_change_1h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_24h")) {
coinmarketcapsnapshotObject.setPercentChange24h((Double) jsonObjectDataCryptoQuotes.get("percent_change_24h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_7d")) {
coinmarketcapsnapshotObject.setPercentChange7d((Double) jsonObjectDataCryptoQuotes.get("percent_change_7d"));
}
entityManager.persist(coinmarketcapsnapshotObject);
coinmarketcapsnapshotsArray.put(coinmarketcapsnapshotObject);
coinmarketcapsnapshotsJSONObject.put(String.valueOf(count),coinmarketcapsnapshotObject);
coinmarketcapsnapshotsHashMap.put(count, coinmarketcapsnapshotObject);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
System.out.println("\n\ncoinmarketcapsnapshotsArray:\n"+coinmarketcapsnapshotsArray);
System.out.println("\n\ncoinmarketcapsnapshotsJSONObject:\n"+coinmarketcapsnapshotsJSONObject);
System.out.println("\n\ncoinmarketcapsnapshotsHashMap:\n"+coinmarketcapsnapshotsHashMap);
return new ResponseEntity<>(coinmarketcapsnapshotsHashMap, HttpStatus.OK);
}
Here is what is printed in the terminal:
coinmarketcapsnapshotsArray:
["com.krown.entity.CoinmarketcapSnapshot@4d60f69f","com.krown.entity.CoinmarketcapSnapshot@4739c2f2","com.krown.entity.CoinmarketcapSnapshot@7d5bd573","com.krown.entity.CoinmarketcapSnapshot@43b5eb6d","com.krown.entity.CoinmarketcapSnapshot@26e1a633"]
coinmarketcapsnapshotsJSONObject:
{"1":"com.krown.entity.CoinmarketcapSnapshot@4d60f69f","2":"com.krown.entity.CoinmarketcapSnapshot@4739c2f2","3":"com.krown.entity.CoinmarketcapSnapshot@7d5bd573","4":"com.krown.entity.CoinmarketcapSnapshot@43b5eb6d","5":"com.krown.entity.CoinmarketcapSnapshot@26e1a633"}
coinmarketcapsnapshotsHashMap:
{1=com.krown.entity.CoinmarketcapSnapshot@4d60f69f, 2=com.krown.entity.CoinmarketcapSnapshot@4739c2f2, 3=com.krown.entity.CoinmarketcapSnapshot@7d5bd573, 4=com.krown.entity.CoinmarketcapSnapshot@43b5eb6d, 5=com.krown.entity.CoinmarketcapSnapshot@26e1a633}
I want to return my JSONObject "coinmarketcapsnapshotsJSONObject" instead "coinmarketcapsnapshotsHashMap", but when I do it, I keep getting stuck with this error:
No converter found for return value of type: class org.json.JSONObject
As suggested in some posts found on web, I added Jackson as new dependency in pom.xml file:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.5.0</version>
</dependency>
Unfortunately this didn't change anything.
Do you have any suggestion to improve the process of building a JSON for a REST API on Spring Boot?
When I return the HashMap, the output looks like that:
Upvotes: 0
Views: 5092
Answers (2)
hd1
Reputation: 34657
HttpStatus.OK is the default return value for Http endpoints using Spring and therefore specifying it is unnecessary, thereby rendering the entire ResponseEntity unnecessary:
@ResponseBody
@Transactional
@GetMapping("create_coinmarketcap_snapshot")
public HashMap create_coinmarketcap_snapshot() {
String jsonString = callURL("https://api.coinmarketcap.com/v2/ticker/?limit=5");
JSONArray coinmarketcapsnapshotsArray = new JSONArray();
JSONObject coinmarketcapsnapshotsJSONObject = new JSONObject();
HashMap<Integer, CoinmarketcapSnapshot> coinmarketcapsnapshotsHashMap = new HashMap<>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONObject jsonObjectData = jsonObject.getJSONObject("data");
Iterator<?> keys = jsonObjectData.keys();
int count = 0;
while (keys.hasNext()) {
count++;
String key = (String) keys.next();
if (jsonObjectData.get(key) instanceof JSONObject) {
JSONObject jsonObjectDataCrypto = jsonObjectData.getJSONObject(key);
JSONObject jsonObjectDataCryptoQuotes = jsonObjectDataCrypto.getJSONObject("quotes").getJSONObject("USD");
CoinmarketcapSnapshot coinmarketcapsnapshotObject = new CoinmarketcapSnapshot();
String dateFormatted = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss").format(Calendar.getInstance().getTime());
coinmarketcapsnapshotObject.setTitle(jsonObjectDataCrypto.get("name") + " - " + dateFormatted);
coinmarketcapsnapshotObject.setCryptocurrencyId((int) jsonObjectDataCrypto.get("id"));
if(jsonObjectDataCrypto.get("rank")!=null){
coinmarketcapsnapshotObject.setRank((int) jsonObjectDataCrypto.get("rank"));
}
if(jsonObjectDataCrypto.get("circulating_supply")!=null){
coinmarketcapsnapshotObject.setCirculatingSupply((Double) jsonObjectDataCrypto.get("circulating_supply"));
}
if(jsonObjectDataCrypto.get("total_supply")!=null){
coinmarketcapsnapshotObject.setTotalSupply((Double) jsonObjectDataCrypto.get("total_supply"));
}
if(!jsonObjectDataCrypto.isNull("circulating_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("circulating_supply"));
}
if(!jsonObjectDataCrypto.isNull("total_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("total_supply"));
}
if(!jsonObjectDataCrypto.isNull("max_supply")) {
coinmarketcapsnapshotObject.setMaxSupply((Double) jsonObjectDataCrypto.get("max_supply"));
}
if(!jsonObjectDataCryptoQuotes.isNull("price")) {
coinmarketcapsnapshotObject.setPrice((Double) jsonObjectDataCryptoQuotes.get("price"));
}
if(!jsonObjectDataCryptoQuotes.isNull("volume_24h")) {
coinmarketcapsnapshotObject.setVolume24h((Double) jsonObjectDataCryptoQuotes.get("volume_24h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("market_cap")) {
coinmarketcapsnapshotObject.setMarketCap((Double) jsonObjectDataCryptoQuotes.get("market_cap"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_1h")) {
coinmarketcapsnapshotObject.setPercentChange1h((Double) jsonObjectDataCryptoQuotes.get("percent_change_1h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_24h")) {
coinmarketcapsnapshotObject.setPercentChange24h((Double) jsonObjectDataCryptoQuotes.get("percent_change_24h"));
}
if(!jsonObjectDataCryptoQuotes.isNull("percent_change_7d")) {
coinmarketcapsnapshotObject.setPercentChange7d((Double) jsonObjectDataCryptoQuotes.get("percent_change_7d"));
}
entityManager.persist(coinmarketcapsnapshotObject);
coinmarketcapsnapshotsArray.put(coinmarketcapsnapshotObject);
coinmarketcapsnapshotsJSONObject.put(String.valueOf(count),coinmarketcapsnapshotObject);
coinmarketcapsnapshotsHashMap.put(count, coinmarketcapsnapshotObject);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
System.out.println("\n\ncoinmarketcapsnapshotsArray:\n"+coinmarketcapsnapshotsArray);
System.out.println("\n\ncoinmarketcapsnapshotsJSONObject:\n"+coinmarketcapsnapshotsJSONObject);
System.out.println("\n\ncoinmarketcapsnapshotsHashMap:\n"+coinmarketcapsnapshotsHashMap);
return coinmarketcapsnapshotsHashMap;
}
Upvotes: 0
user5973985
Reputation:
@GetMapping(produces={MediaType.APPLICATION_JSON_VALUE})
public ResponseEntity<?> create_coinmarketcap_snapshot() throws IOException {
UriComponentsBuilder builder =
UriComponentsBuilder.fromUriString("https://api.coinmarketcap.com/v2/ticker")
.queryParam("limit", "5");
ResponseEntity<String> response =
restTemplate.getForEntity(builder.toUriString(), String.class);
ObjectMapper mapper = new ObjectMapper();
JsonNode root = mapper.readTree(response.getBody());
JsonNode data = root.path("data");
data.forEach(jsonObject -> {
jsonObject.get("rank"); //extracting values from each json object
jsonObject.get("circulating_supply");
jsonObject.get("total_supply");
jsonObject.get("max_supply");
jsonObject.get("price");
jsonObject.get("volume_24h");
jsonObject.get("market_cap");
jsonObject.get("percent_change_1h");
jsonObject.get("percent_change_24h");
//... and so on
});
return ResponseEntity.ok(data);
}
Now you're returning a json object that contains the value of "data" key @118218
Upvotes: 0
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