CODEWITHSUNDEEP
jsonparsingjackson
Chris
Chris

Reputation: 18884

Jackson Parse Specific Array

I am using Jackson to parse api results and this seems to be working well.

Java:

public static void jsonIn(String st){
         try {
        JsonFactory jfactory = new JsonFactory();
        /*** read from URL ***/
        JsonParser jParser = jfactory.createJsonParser(new URL(st));
        // loop until token equal to "}"
        while (jParser.nextToken() != JsonToken.END_ARRAY) {
            String fieldname = jParser.getCurrentName();
            if ("id".equals(fieldname)) {
              // current token is "id",
                      // move to next, which is "id"'s value
            try{
              jParser.nextToken();
                }
            catch (Exception e){

            }
              System.out.println(jParser.getText()); // display id
            }
          }
          jParser.close();
         } catch (JsonGenerationException e) {
          e.printStackTrace();
         } 

      }

Question:

However- the results that I want (field: "id") are in the array "items". The code above starts at the first array "queries" and only sends me the 1 element named "id", which I don't care for. It then stops parsing based on the while statement and doesnt get to the "items" array. How can I change my code above to skip to the array "items" that I am interested in so that I can get the "id" fields that I want?

json:

{
 "app": "Sale",
 "avail": {
  "type": "application/json",
},
 "queries": {
  "unAvailURIs": [
   {
    "id": "1sdf6gf3jf80dhb3",
    "results": "57",
    "searchTerms": "lycos.com",
    "startIndex": 11
   }
  ],
  "apiSource": [
   {
    "title": "go****y",
    "totalResults": "579000",
    "auctionPhrase": "lycos.com",
    "count": 10,
    "startIndex": 1,
    "id": "in",
   }
  ]
 },
 "pullAPI": {
  "search": "lycos.com"
 },
 "searchInformation": {
  "searchTime": 0.025345,
  "totalResults": "57600100",
 },
 "items": [
  {
   "id": "GD172993",
   "title": "lycos.com",
   ....

Upvotes: 2

Views: 3171

Answers (1)

Chris
Chris

Reputation: 18884

I seem to have missed the one SO post I was looking for: Parsing JSON Bing results with Jackson. Thank you to @fge for explaining ObjectMapper and readTree().
I simply replaced the beginning of my top try statement as so:

try {    
    JsonFactory jfactory = new JsonFactory();
    JsonParser jParser = jfactory.createJsonParser(new URL(st));
    ObjectMapper mapper = new ObjectMapper();
    JsonNode input = mapper.readTree(jParser);
    final JsonNode results = input.get("items");
    // loop until token equal to "}"
    for (final JsonNode element: results) {
        JsonNode fieldname = element.get("id");
        System.out.println(fieldname.toString());

Upvotes: 4

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