使用gson解析具有相同名称的json变量对象

Question

Hi I want to parse the json

 {
        "entityType":"Account",


        "values":[
                {
                    "name":"accountType",
                    "type":"lookup",
                    "typeinfo":{"entity":"lov", "filter":"LOV_ACCOUNT_TYPE"}
                },
                {
                    "name":"irstSubType",
                    "type":"lookup",
                    "typeinfo":{"entity":"lov", "filter":"LOV_ACCOUNT_TYPE"}
                },
                {
                    "name":"accountStatus",
                    "type":"lookup",
                    "typeinfo":{"entity":"lov", "filter":"LOV_ACCOUNT_STATUS"}
                },
                {
                    "name":"name",
                    "type":"string",
                    "typeinfo":{"width":80}
                },
                {
                    "name":"updated",
                    "type":"datetime",
                    "typeinfo":{"format":"dd/MM/yyyy hh:MM:ss"}
                }
          ]
    }

So here typeinfo object implementation is changing.. any suggessions how does Gson library accomodate this? Interface does not work.

Answer 1

Value

public class Value {
private String name;
private String type;    
private  TypeInfo typeinfo;
public String getName() {
    return name;
}
public String getType() {
    return type;
}
public TypeInfo getTypeinfo() {
    return typeinfo;
}
}

MyGson

public class MyGson {
private String entityType;
private List<Value> values;

public String getEntityType() {
    return entityType;
}
public List<Value> getValues() {
    return values;
}
}

TypeInfo

public class TypeInfo {

private String format;
private String entry;
private String filter;

public String getFormat() {
    return format;
}

public String getEntry() {
    return entry;
}

public String getFilter() {
    return filter;
}
}

Launcher

    Gson gson = new Gson();

    MyGson myGson = gson.fromJson(str, MyGson.class);

    List<Value> values = myGson.getValues();


    for(Value value : values){

        str = value.getTypeinfo().getFormat();


        printValues("format", value.getTypeinfo().getFormat());
        printValues("entry", value.getTypeinfo().getEntry());
        printValues("filter", value.getTypeinfo().getFilter());
        //....
    }




}

private static void printValues(String key, String data){
    if(data != null){
        System.out.println(key + ": " + data);
    }
}

Output:

filter: LOV_ACCOUNT_TYPE
filter: LOV_ACCOUNT_TYPE
filter: LOV_ACCOUNT_STATUS
format: dd/MM/yyyy hh:MM:ss

Answer 2

Despite the other answers, it is not a good idea to have a field for each of the possible variables in typeinfo, as two fields could have same name but different types.

What you really want to do, is to turn the data from typeinfo into a Map<String, Object>.

This is difficult in Gson, but it is possible using a deserializer - see Kevin's answer for an example of this: https://stackoverflow.com/a/4799594/1660737

Answer 3

        String s = "...json string ..";
        JSONParser jsonparser = new JSONParser();
        JSONObject jsonObject = (JSONObject)jsonparser.parse(s);
        JSONArray values = (JSONArray) jsonObject.get("values");

        for(int i=0; i< values.size(); i++){
            JSONObject value = (JSONObject)values.get(i);
            JSONObject typeInfo = (JSONObject)value.get("typeinfo");
            Iterator it = typeInfo.keySet().iterator();
            while(it.hasNext()){
                Object key = it.next();
                System.out.println("KEY:" + key + " VALUE:" + typeInfo.get(key));
            }
        }