Convert JSON string back to Java List

Question

I am using gson to convert a List to a JSON string and back to List.I am getting a ClassCastException while converting the objects in the list back to string.I would be grateful for any assistance.

public void JSONTest()    
{

    List<String> list=new ArrayList();
    list.add("a");
    list.add("b");
    list.add("c");
    System.out.println(list);
    Gson gsonSender = new Gson();
    String json = gsonSender.toJson(list);
    System.out.println(json);
    Gson gsonReceiver = new Gson();
    List obj = gsonReceiver.fromJson(json, List.class);
    Iterator it=obj.iterator();
    while(it.hasNext())
    {
        System.out.println((String)it.next());//java.lang.ClassCastException: java.lang.Object cannot be cast to java.lang.String
    }

}

Sameer Sarmah · Accepted Answer · 2014-05-07 10:04:19Z

8

Type type = new TypeToken<List<String>>(){}.getType();
 List<String> obj = gsonReceiver.fromJson(json,type);

Type is from java.lang.reflect.Type and TypeToken is from com.google.gson.reflect.TypeToken.

answered May 7, 2014 at 10:04

Sameer Sarmah

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1 Comment

user801154 Over a year ago

What is this syntax: {} after Type type = new TypeToken<List<String>>()

Gundamaiah · Accepted Answer · 2014-05-07 09:58:31Z

0

Try this

List<String> obj = gsonReceiver.fromJson(json, List.class);

answered May 7, 2014 at 9:58

Gundamaiah

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