converting string to gson object

Question

I have a string output from server and I am trying to extract some values form the string.

Here is the output from server:

jsonString =

{
  "MEANING":"reduce",
  "DISPLAY":"",
  "TYPE_CD":1,
  "SELECTED_IND":1,
  "CNT":1,
  "SOURCES":[
              { "a":1 }
            ]
}

Code:

JsonReader reader = new JsonReader(new StringReader(jsonString));
DataObject obj1 = new Gson().fromJson(reader, DataObject.class);

DataObject Class:

DataObject
{ 
    private int MEANING;
    private int CNT;
    private String TYPE_CD;
    private String DISPLAY;
    private String MEANING;
    private List<Long> SOURCES;

    public String getSourceTypeMeaning()
     {
       return this.MEANING;
     }

    public String getSourceTypeDisplay() 
     {
       return this.DISPLAY;
     }

    public String getSourceTypeCd() 
     {
       return this.TYPE_CD;
     }

    public int getSourceCount() 
     {
       return this.CNT;
     }

    public List<Long> getSourceList() 
     {
       return this.SOURCES;
     }
}

but getting this error

Expected a string but was BEGIN_OBJECT at line 1 column 132

I am not able to find the issue with my code.

MikO · Accepted Answer · 2013-07-16 12:27:11Z

1

Other answers are pointing out that the problem is in the SOURCES field, and that's true, but the solutions they're giving are not correct...

You can't use just a Map to parse the SOURCES field, because this field is indeed an array! You have:

"SOURCES": [ ... ]

Since you have square brackets [ ], you have an array! And it's true there's a Map, but it is contained in the array...

So, what you need to parse that field correctly is:

private List<Map<String, int>> SOURCES;

Note that we use a Map to allow the content of SOURCES to have multiple and unknown values, so that this code could parse not only your JSON, but also something like:

"SOURCES":[
              { "a":1, "b":2 },
              { "c":3 },
              { "x":99, "y":98, "z":97 }
          ]

edited Jul 16, 2013 at 12:27

answered Jul 16, 2013 at 11:15

MikO

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Comments

Buhake Sindi · Accepted Answer · 2013-07-16 05:31:58Z

0

SOURCES variable should be Map<String,Long>,because in JSON string SOURCES is key-value collection ("a":1) where "a" is string and 1 is number.

Hope this helps.

edited Jul 16, 2013 at 5:31

Buhake Sindi

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answered Jul 16, 2013 at 5:27

Ilyas Alikhojayev

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2 Comments

user1772643 Over a year ago

I changed my code to use HashMap, still getting a error. private HashMap<String, Long> SOURCES; public HashMap<String, Long> getSourceList() { return this.SOURCES; } Still getting an error saying "Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1"

MikO Over a year ago

-1, wrong answer: SOURCES field is clearly a JSON array since it has square brackets [ ]...

Ashish Aggarwal · Accepted Answer · 2013-07-16 12:21:32Z

0

Check this

"SOURCES":[
              { "a":1 }
 ]

This will represent a List of map not List of long.

So change your List<long> to List<Map<String, Long>> or List<Map<Object, Long>>.

edited Jul 16, 2013 at 12:21

answered Jul 16, 2013 at 5:29

Ashish Aggarwal

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2 Comments

Ashish Aggarwal Over a year ago

@shanku sorry to say but I didn't copy the ans. When I submit my ans after that I see that the same ans is already submitted and when I start writting ans there is no ans present at that time.

MikO Over a year ago

-1, wrong answer: SOURCES field does represent a List since it has square brackets [ ]...

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