Gson用法一

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写项目的时候，对于json解析和生成是很繁琐的，特别是数据比较多的时候，现在普遍都是用Gson和fastJson解析，下面就介绍一下Gson的用法：
之前我也写过一点点关于gson的使用方法：http://blog.csdn.net/biao_suki/article/details/47682165
但是之前这样gson解析也是很麻烦的，主要是写实体类的时候很麻烦，所以我推荐用GsonFormat这个插件来生成实体类，非常快捷方便的一个插件
有了这个插件我就不介绍，怎么写实体类了，就说一下Gson的简单用法
在网上拿了一段json数据，就用它来做测试

{    "error": 0,    "status": "success",    "date": "2014-05-10",    "results": [        {            "currentCity": "南京",            "weather_data": [                {                    "date": "周六(今天, 实时：19℃)",                    "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/dayu.png",                    "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/dayu.png",                    "weather": "大雨",                    "wind": "东南风5-6级",                    "temperature": "18℃"                },                {                    "date": "周日",                    "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/zhenyu.png",                    "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",                    "weather": "阵雨转多云",                    "wind": "西北风4-5级",                    "temperature": "21 ~ 14℃"                }            ]        }    ]}

根据这个json数据就用上面提到的GsonFormat插件来写实体类

public class Weather {    /**     * error : 0     * status : success     * date : 2014-05-10     * results : [{"currentCity":"南京","weather_data":[{"date":"周六(今天, 实时：19℃)","dayPictureUrl":"http://api.map.baidu.com/images/weather/day/dayu.png","nightPictureUrl":"http://api.map.baidu.com/images/weather/night/dayu.png","weather":"大雨","wind":"东南风5-6级","temperature":"18℃"},{"date":"周日","dayPictureUrl":"http://api.map.baidu.com/images/weather/day/zhenyu.png","nightPictureUrl":"http://api.map.baidu.com/images/weather/night/duoyun.png","weather":"阵雨转多云","wind":"西北风4-5级","temperature":"21 ~ 14℃"}]}]     */    private int error;    private String status;    private String date;    /**     * currentCity : 南京     * weather_data : [{"date":"周六(今天, 实时：19℃)","dayPictureUrl":"http://api.map.baidu.com/images/weather/day/dayu.png","nightPictureUrl":"http://api.map.baidu.com/images/weather/night/dayu.png","weather":"大雨","wind":"东南风5-6级","temperature":"18℃"},{"date":"周日","dayPictureUrl":"http://api.map.baidu.com/images/weather/day/zhenyu.png","nightPictureUrl":"http://api.map.baidu.com/images/weather/night/duoyun.png","weather":"阵雨转多云","wind":"西北风4-5级","temperature":"21 ~ 14℃"}]     */    private List<ResultsBean> results;    public int getError() {        return error;    }    public void setError(int error) {        this.error = error;    }    public String getStatus() {        return status;    }    public void setStatus(String status) {        this.status = status;    }    public String getDate() {        return date;    }    public void setDate(String date) {        this.date = date;    }    public List<ResultsBean> getResults() {        return results;    }    public void setResults(List<ResultsBean> results) {        this.results = results;    }    public static class ResultsBean {        private String currentCity;        /**         * date : 周六(今天, 实时：19℃)         * dayPictureUrl : http://api.map.baidu.com/images/weather/day/dayu.png         * nightPictureUrl : http://api.map.baidu.com/images/weather/night/dayu.png         * weather : 大雨         * wind : 东南风5-6级         * temperature : 18℃         */        private List<WeatherDataBean> weather_data;        public String getCurrentCity() {            return currentCity;        }        public void setCurrentCity(String currentCity) {            this.currentCity = currentCity;        }        public List<WeatherDataBean> getWeather_data() {            return weather_data;        }        public void setWeather_data(List<WeatherDataBean> weather_data) {            this.weather_data = weather_data;        }        public static class WeatherDataBean {            private String date;            private String dayPictureUrl;            private String nightPictureUrl;            private String weather;            private String wind;            private String temperature;            public String getDate() {                return date;            }            public void setDate(String date) {                this.date = date;            }            public String getDayPictureUrl() {                return dayPictureUrl;            }            public void setDayPictureUrl(String dayPictureUrl) {                this.dayPictureUrl = dayPictureUrl;            }            public String getNightPictureUrl() {                return nightPictureUrl;            }            public void setNightPictureUrl(String nightPictureUrl) {                this.nightPictureUrl = nightPictureUrl;            }            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 getTemperature() {                return temperature;            }            public void setTemperature(String temperature) {                this.temperature = temperature;            }            @Override            public String toString() {                return "WeatherDataBean{" +                        "date='" + date + '\'' +                        ", dayPictureUrl='" + dayPictureUrl + '\'' +                        ", nightPictureUrl='" + nightPictureUrl + '\'' +                        ", weather='" + weather + '\'' +                        ", wind='" + wind + '\'' +                        ", temperature='" + temperature + '\'' +                        '}';            }        }        @Override        public String toString() {            return "ResultsBean{" +                    "currentCity='" + currentCity + '\'' +                    ", weather_data=" + weather_data +                    '}';        }    }    @Override    public String toString() {        return "Weather{" +                "error=" + error +                ", status='" + status + '\'' +                ", date='" + date + '\'' +                ", results=" + results +                '}';    }}

1、json数据转换成泛型

Gson gson = new Gson();Type type = new TypeToken<Weather>() {}.getType();Weather weather = gson.fromJson(str, type);

2、泛型转换成Json数据

Gson gson = new Gson();String str = gson.toJson(weather);

有了GsonFormat，解析json或者生成json都非常简单，基本上能解析大部分的Json数据
DEMO

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