json（gson）解析会在解析时更改数据类型

Question

I have a json string which looks something like this :

{"employees":[
    {"firstName":"John", "lastName":"Doe"},
    {"firstName":"Anna", "lastName":"Smith"},
    {"firstName":"Peter", "lastName":"Jones"}
]}

When I use gson parser to convert that to a Map<String,String> map . The gson converts the type to Map<String,ArrayList> . And when I try to print the class name using System.out.println(map.get("employees").getClass().toString()) . But this throws an exception - java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.lang.String .

my code looks something like this

String npv = json_string_provided_above;
Map<String,String> mp = new HashMap<String, String>();
mp = new Gson().fromJson(npv,mp.getClass());
System.out.println(mp.get("employees").getClass().toString());

The json is given as input by user in string format(and it will always be a valid json string). And one thing is sure that I can't assume anything about the type of data. Because it will be provided by user.

So now actually I want that even If the user inputs something like arrays of string or arrays of objects. It should not convert the them to List,

Is there is a way I can hard code the type and keep them in Map<String,String> . so in the above example when I do map.get("employees") it should give me the [{"firstName":"John", "lastName":"Doe"},{"firstName":"Anna", "lastName":"Smith"},{"firstName":"Peter", "lastName":"Jones"}] as string not list. I am not sure how to do this.

Thank you for your help,

Answer 1

Jon is right, just use Map<String, Object>

String npv = json_string_provided_above;
Map<String,Object> mp = new HashMap<String, Object>();
mp = new Gson().fromJson(npv, mp.getClass());
System.out.println(mp.get("employees").toString());