Java Gson 简要笔记

Gson是Google开发的Java比较好用的 Json工具。

使用挺简单，假设有个类:

1 class Runner {
2     int attr;
3     String name;
4     public Runner(int attr, String name)   {
5         this.attr = attr;
6         this.name = name;        
7     }
8 }

Object -> JSON （关键 line 3）:

1 Gson gson = new Gson();
2 Runner runner = new Runner(3, "lhfcws");
3 String jsonStr = gson.toJson(runner);
4 System.out.println(jsonStr);

JSON -> Object:

1 Gson gson = new Gson();
2 String jsonStr = "....";
3 Runner runner = gson.fromJson(jsonStr, Runner.class);

当遇到泛型的时候，fromJson最好使用另一种方法，TypeToken。不然有时会把对象识别成LinkedHashMap结构：

1 Gson gson = new Gson();
2 String jsonStr = "....";
3 List<Runner> runnerList = gson.fromJson(jsonStr, new TypeToken<List<Runner>>(){}.getType());