GSON to Map

GsonTest.java

import com.google.gson.Gson;

import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;


public class GsonTest {
    public static void main(String[] args) {
        LinkedHashMap<String, Object> map = new LinkedHashMap<String, Object>();
        map.put("attr1", "hoge");
        LinkedHashMap<String, Object> innerMap1 = new LinkedHashMap<String, Object>();
        innerMap1.put("in1", "foo");
        innerMap1.put("in2", 12);
        LinkedHashMap<String, Object> innerMap2 = new LinkedHashMap<String, Object>();
        innerMap2.put("inin1", "to");
        innerMap1.put("in3", innerMap2);
        LinkedList<String> innerArray1 = new LinkedList<String>();
        innerArray1.add("hya");
        innerArray1.add("gya");
        innerArray1.add("pya");
        map.put("attr2", innerMap1);
        innerMap2.put("inin2", innerArray1);
        Gson gson = new Gson();
        System.out.println(gson.toJson(innerMap1));
        System.out.println(gson.toJson(map));

        Map obj = gson.fromJson(gson.toJson(map), Map.class);
        System.out.println("- - - - -");
        System.out.println(obj.getClass());
        System.out.println(obj);
        System.out.println("- - - - -");
        System.out.println(obj.get("attr1").getClass());
        System.out.println(obj.get("attr1"));
        System.out.println("- - - - -");
        System.out.println(obj.get("attr2").getClass());
        System.out.println(obj.get("attr2"));
        System.out.println("- - - - -");
        System.out.println(Map.class.cast(obj.get("attr2")).get("in1").getClass());
        System.out.println(Map.class.cast(obj.get("attr2")).get("in1"));
        System.out.println("- - - - -");
        System.out.println(Map.class.cast(obj.get("attr2")).get("in2").getClass());
        System.out.println(Map.class.cast(obj.get("attr2")).get("in2"));
        System.out.println("- - - - -");
        System.out.println(Map.class.cast(obj.get("attr2")).get("in3").getClass());
        System.out.println(Map.class.cast(obj.get("attr2")).get("in3"));
        System.out.println("- - - - -");
        System.out.println(Map.class.cast(Map.class.cast(obj.get("attr2")).get("in3")).get("inin2").getClass());
        System.out.println(Map.class.cast(Map.class.cast(obj.get("attr2")).get("in3")).get("inin2"));
    }
}

{"in1":"foo","in2":12,"in3":{"inin1":"to","inin2":["hya","gya","pya"]}}
{"attr1":"hoge","attr2":{"in1":"foo","in2":12,"in3":{"inin1":"to","inin2":["hya","gya","pya"]}}}

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class com.google.gson.internal.LinkedTreeMap
{attr1=hoge, attr2={in1=foo, in2=12.0, in3={inin1=to, inin2=[hya, gya, pya]}}}

---

class java.lang.String
hoge

---

class com.google.gson.internal.LinkedTreeMap
{in1=foo, in2=12.0, in3={inin1=to, inin2=[hya, gya, pya]}}

---

class java.lang.String
foo

---

class java.lang.Double
12.0

---

class com.google.gson.internal.LinkedTreeMap
{inin1=to, inin2=[hya, gya, pya]}

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class java.util.ArrayList
[hya, gya, pya]