FastJson和Gson和Json数据解析分析和用法

首先分析下目前号称最快的FastJson，这个是所有人都验证过的，解析速度确实比较快，不过也需要根据数据量来看，数据量小的时候，Gson性能要稍微优于FastJson，但在数据量大解析的情况下，FastJson的速度就要明显快于Gson。具体原因，我没研究过，只是做过测试，确实是这样。

性能测试代码如下：

/** * 测试Bean类 */
public class TestBean {
    private String name;
    private int age;
    private String no;

    public TestBean() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int j) {
        this.age = j;
    }

    public String getNo() {
        return no;
    }

    public void setNo(String no) {
        this.no = no;
    }

}

/** * 比较FastJson和Gson的效率 */
    public void comparedFastJsonAndGson() {
        List<TestBean> list = new ArrayList<>();
        int j = 0;
        TestBean u = null;
        //数据生成
        while (j < 1000000) {
            u = new TestBean();
            u.setAge(j);
            u.setName("zhangsan " + j);
            u.setNo("" + j);
            list.add(u);
            j++;
        }
        //做测试时，两个方法不要同时使用，注释掉另一个分别运行，然后再比较时间，不然结果不准
        // FastJson性能测试
        fastJsonTest(list);
        System.out.println("!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
        // Gson性能测试
        gsonTest(list);
    }

    /** * FastJsonTest * * @param list */
    private void fastJsonTest(List<TestBean> list) {
        long s = System.currentTimeMillis();
        System.out.println("before alibaba:" + s);
        String aliJson = com.alibaba.fastjson.JSON.toJSONString(list);
        long e = System.currentTimeMillis();
        System.out.println("after alibaba:" + e);
        System.out.println("beanToJson:" + (e - s));
        list = null;
        long s3 = System.currentTimeMillis();
        List<TestBean> sult = JSON.parseArray(aliJson, TestBean.class);
        // List<U> sult = (List<U>) JSONObject.parse(aliJson);
        long e3 = System.currentTimeMillis();
        System.out.println("JsonTobean:" + (e3 - s3));
    }

    /** * GsonTest * * @param list */
    private void gsonTest(List<TestBean> list) {
        long s1 = System.currentTimeMillis();
        System.out.println("before Gson:" + s1);
        Gson gson = new Gson();
        String gsonStr = gson.toJson(list);
        long e1 = System.currentTimeMillis();
        System.out.println("after Gson:" + e1);
        System.out.println("beanToJson:" + (e1 - s1));
        list = null;
        long s4 = System.currentTimeMillis();
        // type 获取List<U>类型的class
        Type type = new TypeToken<List<TestBean>>() {
        }.getType();
        List<TestBean> sult2 = gson.fromJson(gsonStr, type);
        long e4 = System.currentTimeMillis();
        System.out.println("JsonTobean:" + (e4 - s4));
    }

---

下面介绍下两种解析方式的具体使用方法（这里使用的是K780数据网的5~7天天气预报信息）

/** * @author Jerry 2016.4.15 * */
public class Weather {
    private String days; // 日期
    private String week; // 星期
    private String citynm; // 城市/地区
    private String temperature;// 温度
    private String weather; // 天气
    private String wind;// 风向
    private String winp;// 风力

    public Weather() {
    }

    public String getDays() {
        return days;
    }

    public void setDays(String days) {
        this.days = days;
    }

    public String getWeek() {
        return week;
    }

    public void setWeek(String week) {
        this.week = week;
    }

    public String getCitynm() {
        return citynm;
    }

    public void setCitynm(String citynm) {
        this.citynm = citynm;
    }

    public String getTemperature() {
        return temperature;
    }

    public void setTemperature(String temperature) {
        this.temperature = temperature;
    }

    public String getWeather() {
        return weather;
    }

    public void setWeather(String weather) {
        this.weather = weather;
    }

    public String getWind() {
        return wind;
    }

    public void setWind(String wind) {
        this.wind = wind;
    }

    public String getWinp() {
        return winp;
    }

    public void setWinp(String winp) {
        this.winp = winp;
    }

    @Override
    public String toString() {
        return "Weather [days=" + days + ", week=" + week + ", citynm=" + citynm + ", temperature=" + temperature
                + ", weather=" + weather + ", wind=" + wind + ", winp=" + winp + "]";
    }
}

/** * @author Jerry */
public class WeatherGson {
    private String success;
    private List<Weather> result; // 此处List 名字，必须为Json数组中键的名字，必须相同

    public WeatherGson() {
    }

    public WeatherGson(String success, List<Weather> result) {
        this.success = success;
        this.result = result;
    }

    public String getSuccess() {
        return success;
    }

    public void setSuccess(String success) {
        this.success = success;
    }

    public List<Weather> getList() {
        return result;
    }

    public void setList(List<Weather> list) {
        this.result = list;
    }

    @Override
    public String toString() {
        return "WeatherJson [success=" + success + ", list=" + result + "]";
    }   
}

---

以下所以方法都卸载JsonDemo类中

/** * 获取网络Json数据String * * @param weaid * @return */
    public String getJsonData() {
        System.out.println("请等待...");

        String url = "http://api.k780.com:88/?app=weather.future&weaid=1&&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json";
        //将获取到的数据转换成字符串，此处是我自己封装的工具类
        String jsonData = HttpUitls.doPostToString(url, "utf-8");
        return jsonData;
    }

首先是FastJson的解析：

/** * fastJson 解析 * * @param jsonData * @return */
    public List<Weather> fastJsonParser(String jsonData) {
        // 获取jsonObject对象
        JSONObject object = JSON.parseObject(jsonData);
        String success = object.getString("success");
        if ("1".equals(success)) {
            // 从jsonObject对象中获取 result 对象的值（Json数组）
            String result = object.getString("result");
            // 将Json数组转换成List集合
            List<Weather> list = JSON.parseArray(result, Weather.class);
            return list;
        } else {
            throw new RuntimeException("获取信息失败:" + success);
        }
    }

接着是Gson的解析：

/** * Gson 解析 * * @param jsonData */
    public List<Weather> gsonParser(String jsonData) {
        Gson gson = new Gson();
        System.out.println(jsonData);
        // List<Weather> list2 = gson.fromJson(jsonData, new
        // TypeToken<List<Weather>>(){}.getType());
        WeatherGson fromJson = gson.fromJson(jsonData, WeatherGson.class);
        if ("1".equals(fromJson.getSuccess())) {
            return fromJson.getList();
        } else {
            throw new RuntimeException("获取信息失败:" + fromJson.getSuccess());
        }
    }

最后是Json解析：

/** * Json解析 * * @param jsonData * @return */
    public List<Weather> jsonParser(String jsonData) {
        list = new ArrayList<>();
        try {
            org.json.JSONObject object = new org.json.JSONObject(jsonData);
            JSONArray result = object.getJSONArray("result");
            for (int i = 0; i < result.length(); i++) {
                org.json.JSONObject object2 = result.getJSONObject(i);
                this.weather = new Weather();
                String days = object2.getString("days");
                String week = object2.getString("week");
                String citynm = object2.getString("citynm");
                String temperature = object2.getString("temperature");
                String weather = object2.getString("weather");
                String wind = object2.getString("wind");
                String winp = object2.getString("winp");
                this.weather.setDays(days);
                this.weather.setWeek(week);
                this.weather.setCitynm(citynm);
                this.weather.setTemperature(temperature);
                this.weather.setWeather(weather);
                this.weather.setWind(wind);
                this.weather.setWinp(winp);
                list.add(this.weather);
            }
            return list;
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

Main：

public class Main {

    public static void main(String[] args) {
        JsonDemo jsonDemo = new JsonDemo();
        // 比较FastJson和Gson 的效率
        jsonDemo.comparedFastJsonAndGson();

        // 从网络获取Json数据
         String jsonData = jsonDemo.getJsonData();

        // 使用Json获取数据集合
        List<Weather> list = jsonDemo.jsonParser(jsonData);
        for (Weather weather : list) {
            System.out.println(weather);
        }

        // 使用FastJson 获取数据集合
        List<Weather> list2 = jsonDemo.fastJsonParser(jsonData);
        for (Weather weather : list2) {
            System.out.println(weather);
        }

        // 使用Gson 获取数据集合
        List<Weather> list3 = jsonDemo.gsonParser(jsonData);
        for (Weather weather : list3) {
            System.out.println(weather);
        }
    }
}

from: http://www.voidcn.com/blog/ming2316780/article/p-5811077.html