使用gson的tojson和fromjson实现对象和json的转换

Gson gson = new Gson(); // Or use new GsonBuilder().create();

     MyType target = new MyType();

     String json = gson.toJson(target); // serializes target to Json

     MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2

 

 Type listType = new TypeToken<List<String>>() {}.getType();

     List<String> target = new LinkedList<String>();

     target.add("blah");

     Gson gson = new Gson();

     String json = gson.toJson(target, listType);

     List<String> target2 = gson.fromJson(json, listType);

 

 使用GsonBuilder创建gson对象

      Gson gson = new GsonBuilder()

         .registerTypeAdapter(Id.class, new IdTypeAdapter())

         .enableComplexMapKeySerialization()

         .serializeNulls()

         .setDateFormat(DateFormat.LONG)

         .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)

         .setPrettyPrinting()

         .setVersion(1.0)

         .create();

 

           Gson gson = new GsonBuilder()

       .register(Point.class, new MyPointTypeAdapter())

       .enableComplexMapKeySerialization()

       .create();

 

map对象转换成json对象

  Gson gson = new GsonBuilder()

       .register(Point.class, new MyPointTypeAdapter())

       .enableComplexMapKeySerialization()

       .create();

   Map<Point, String> original = new LinkedHashMap<Point, String>();

   original.put(new Point(5, 6), "a");

   original.put(new Point(8, 8), "b");

   System.out.println(gson.toJson(original, type));

 

    The above code prints this JSON object:

  {

     "(5,6)": "a",

     "(8,8)": "b"

   }

 map对象转化成jsonArray对象：

Gson gson = new GsonBuilder()       .enableComplexMapKeySerialization()       .create();   Map
    
      original = new LinkedHashMap
     
      ();   original.put(new Point(5, 6), "a");   original.put(new Point(8, 8), "b");   System.out.println(gson.toJson(original, type));  The JSON output would look as follows:
     
    

[     [       {         "x": 5,         "y": 6       },       "a"     ],     [       {         "x": 8,         "y": 8       },       "b"     ]   ]

JsonParser

parse方法将json类型的字符串，或者reader对象或者JsonReader对象解析成为jsonElement对象