Gson解析Json数据（二）

Gson对Json文件的读写

很多时候我们需要对Json文件进行读取，用来保存数据与对象的重新生成。
接上节内容，我将读取的是以下类的数据：

static class Obj {
    private int x;
    private int y;
    private LinkedList interObjList;
    Obj(int x, int y, LinkedList list) {
        this.x = x;
        this.y = y;
        this.interObjList = list;
    }
    static class interObj {
        private int a;
        private int b;
        public interObj(int a, int b) {
            this.a = a;
            this.b = b;
        }
        @Override
        public String toString() {
            return "interObj{" +
                    "a='" + a +
                    ", b=" + b +
                    '}';
        }
    }

    LinkedList getInterObjList()
    {
        return interObjList;
    }
    void setX(int x) {
        this.x = x;
    }

    void setY(int y) {
        this.y = y;
    }

    int getX() {
        return x;
    }

    int getY() {
        return y;
    }



    @Override
    public String toString() {
        return "Obj{" +
                "x='" + x +
                ", y=" + y +
                '}';
    }

}

生成json数据：

List objList = new LinkedList<>();
for(int i = 0; i < 10; ++i) {
    LinkedList list = new LinkedList<>();
    for(int j = 0; j < i + 1; ++j) {
        list.add(new Obj.interObj(j, j + 1));
    }
    objList.add(new Obj(i, 2*i, list));
}

生成数据如下：

[{"x":0,"y":0,"interObjList":[{"a":0,"b":1}]},{"x":1,"y":2,"interObjList":[{"a":0,"b":1},{"a":1,"b":2}]},{"x":2,"y":4,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3}]},{"x":3,"y":6,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4}]},{"x":4,"y":8,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5}]},{"x":5,"y":10,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5},{"a":5,"b":6}]},{"x":6,"y":12,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5},{"a":5,"b":6},{"a":6,"b":7}]},{"x":7,"y":14,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5},{"a":5,"b":6},{"a":6,"b":7},{"a":7,"b":8}]},{"x":8,"y":16,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5},{"a":5,"b":6},{"a":6,"b":7},{"a":7,"b":8},{"a":8,"b":9}]},{"x":9,"y":18,"interObjList":[{"a":0,"b":1},{"a":1,"b":2},{"a":2,"b":3},{"a":3,"b":4},{"a":4,"b":5},{"a":5,"b":6},{"a":6,"b":7},{"a":7,"b":8},{"a":8,"b":9},{"a":9,"b":10}]}]

写入文件：

Gson gson = new Gson();
String jsonData = gson.toJson(objList);
try {
    FileWriter writer = new FileWriter("/home/sar/Desktop/data.json");
    writer.write(jsonData);
    writer.flush();
    writer.close();
    System.out.println(jsonData);
}
catch (Exception ex) {
    ex.printStackTrace();
}

读取文件：

BufferedReader bufferedReader = new BufferedReader(new FileReader("/home/sar/Desktop/data.json"));
Type listType = new TypeToken>(){}.getType();
LinkedList objs = gson.fromJson(bufferedReader, listType);
for(Obj o : objs) {
    LinkedList.interObj> interObjs = o.getInterObjList();
    for(Obj.interObj interObj : interObjs) {
        System.out.println(interObj);
    }
}
bufferedReader.close();

以下是读取结果：（即，将所有Obj中的interObjList打印出来）

interObj{a='0, b=1}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='5, b=6}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='5, b=6}
interObj{a='6, b=7}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='5, b=6}
interObj{a='6, b=7}
interObj{a='7, b=8}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='5, b=6}
interObj{a='6, b=7}
interObj{a='7, b=8}
interObj{a='8, b=9}
interObj{a='0, b=1}
interObj{a='1, b=2}
interObj{a='2, b=3}
interObj{a='3, b=4}
interObj{a='4, b=5}
interObj{a='5, b=6}
interObj{a='6, b=7}
interObj{a='7, b=8}
interObj{a='8, b=9}
interObj{a='9, b=10}