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Failure to deserialize JSON object

开发者 https://www.devze.com 2023-04-12 14:11 出处:网络
I\'m trying to parse the following JSON string using GSON in my Android app: {\"Links\":[{\"Name\":\"Facebook\",\"URL\":\"http://www.facebook.com/\"},{\"Name\":\"Twitter\",\"URL\":\"http://twitter.co

I'm trying to parse the following JSON string using GSON in my Android app:

{"Links":[{"Name":"Facebook","URL":"http://www.facebook.com/"},{"Name":"Twitter","URL":"http://twitter.com/"},{"Name":"Last FM","URL":"http://www.last.fm/"},{"Name":"Hyves","URL":"http://hyves.nl"},{"Name":"My Space","URL":"http://www.myspace.com/"},{"Name":"YouTube","URL":"http://www.youtube.com/"}]}

When doing this, GSON gives me the following exception:

10-13 11:09:23.103: DEBUG/Error:(752): The JsonDeserializer com.google.gson.DefaultTypeAdapters$CollectionTypeAdapter@44e9e430 failed to deserialize json object 
{"Links":[{"Name":"Facebook","URL":"http://www.facebook.com/"},{"Name":"Twitter","URL":"http://twitter.com/"},{"Name":"Last FM","URL":"http://www.last.fm/"},{"Name":"Hyves","URL":"http://hyves.nl"},{"Name":"My Space","URL":"http://www.myspace.com/"},{"Name":"YouTube","URL":"http://www.youtube.com/"}]} 
given the type java.util.List<com.sander.app.json.links.Links>

Now I am a complete novice to JSON, so I'm pretty sure I must be doing something wrong.

I'm using this method to parse my JSON:

       WebService webService = new WebService("http://*********/GetLinksData");

       //Pass the parameters 
       Map<String, String> params = new HashMap<String, String>();
       params.put("iAppID", "59");
       params.put("iFormID", "461");

       //Get JSON response from server the "" are where the method name would normally go if needed example
       // webService.webGet("getMoreAllerts", params);
       String response = webService.webGet("", params);
       System.out.println("Returns: "+response);

       try
       {
           //Parse Response into our object
           Type collectionType = new TypeToken<List<Links>>(){}.getType();
           List<Links> alrt = new Gson().fromJson(response, collectionType);


       }
       catch(Exception e)
       {
           Log.d("Error: ", e.getMessage());
       }
}

And this is my Links class:

public class Links {


public String Name;


public String URL;

public Links(String name, String URL){
    this.Name = name;
    this.URL = URL;
}

@Override
public String toString(){
    return "Name: " + Name + "URL: " + URL;
}}

How might I be able to fix this problem? I have been stuck on this for two da开发者_如何学Goys now, and even though I want to learn how to fix things like this by myself, I'm running out of options.

Regards,

Sander

===================================================

Fixed with the help of Raunak:

public class LinkStorer { public Link Links[];

public Link[] getLinks(){
    return Links;
}

public Link getSingleLink(int i){
    return Links[i];
}

public static class Link {
    public String Name;
    public String URL;

    public String getName() {
        return Name;
    }

    public String getURL() {
        return URL;
    }
}}

Call for JSON object:

LinkStorer collection = new Gson().fromJson(response, LinkStorer.class);
           for(int i=0; i < collection.Links.length; i++){
               System.out.println(collection.getSingleLink(i).getName());


You have the right idea with regards to making a separate class for links, though, it should look something like this

public class Type {
    public Link Links[];

    public static class Link {
        public String Name;
        public String URL;

        public String getName() {
            return Name;
        }

        public String getURL() {
            return URL;
        }
    }
}

You can then convert your json string into java object like this:

Type collection = new Gson().fromJson(response, Type.class);


Maybe the problem that when you define the format of JSON input. Your program expects the following JSON.

[{"Name":"Facebook","URL":"http://www.facebook.com/"},{"Name":"Twitter","URL":"http://twitter.com/"},{"Name":"Last FM","URL":"http://www.last.fm/"},{"Name":"Hyves","URL":"http://hyves.nl"},{"Name":"My Space","URL":"http://www.myspace.com/"},{"Name":"YouTube","URL":"http://www.youtube.com/"}]

Try to create another POJO

public class LinksSearchResult {

private List<Links> links; 

 public List<Links> getLinks() {
    return links;
 }

}

And use fromJSON like this

LinksSearchResult links = new Gson().fromJson(response, collectionType);

Sorry but at this moment i'm unable to try this properly.


Perhaps GSON can only deserialize a JSON object to a standard Java type? In your case, it may be some thing like List<HashMap<String, List<String>>>. Once you have this, you can iterate through the native Java object to generate your custom object.

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