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:

class Runner {
    int attr;
    String name;
    public Runner(int attr, String name)   {
        this.attr = attr;
        this.name = name;        
    }
}

Object -> JSON （关键 line 3）:

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

JSON -> Object:

Gson gson = new Gson();
String jsonStr = "....";
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：

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