将字符串转换为gson对象

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.

Answer 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 }
          ]

Answer 2

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.

Answer 3

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>> .