使用cJSON库解析JSON

cJSON库的下载

cJSON是一个基于C的JSON解析库，这个库非常简单，只有cJSON.c和cJSON.h两个文件，支持JSON的解析和封装，需要调用时，只需要#include "cJSON.h"就可以使用了，

• 库源码下载地址：cJSON download

• JSON官方网站：json

只包含键值对的JSON字符串解析

JSON字符串：

{"name": "Andy",      //键值对1"age": 20              //键值对2
}

这个JSON对象只有两个键值对，键name对应字符串Andy，键age对应数字20。

void Parse_Str1(void)
{char str1[] = "{\"name\":\"Andy\",\"age\":20}";cJSON *str1_json, *str1_name, *str1_age;printf("str1:%s\n\n",str1);str1_json = cJSON_Parse(str1);   //创建JSON解析对象，返回JSON格式是否正确if (!str1_json){printf("JSON格式错误:%s\n\n", cJSON_GetErrorPtr()); //输出json格式错误信息}else{printf("JSON格式正确:\n%s\n\n",cJSON_Print(str1_json) );str1_name = cJSON_GetObjectItem(str1_json, "name"); //获取name键对应的值的信息if (str1_name->type == cJSON_String){printf("姓名:%s\r\n", str1_name->valuestring);}str1_age = cJSON_GetObjectItem(str1_json, "age");   //获取age键对应的值的信息if(str1_age->type==cJSON_Number){printf("年龄:%d\r\n", str1_age->valueint);}cJSON_Delete(str1_json);//释放内存}
}

运行结果：

包含数组的JSON字符串解析

JSON字符串：

{"location": [{"name": "Faye","address": "北京"},{"name": "Andy","address": "香港"}],"time": "2018-11-17"
}

解析函数：

void Parse_Str2(void)
{char str2[] = "{\"location\":[{\"name\":\"Faye\",\"address\":\"北京\"},{\"name\":\"Andy\",\"address\":\"香港\"}],\"time\":\"2018-11-17\"}";cJSON *root = 0;cJSON *loc_json = 0;cJSON *name1_json,*name2_json;char *time_str, *str_tmp;root = cJSON_Parse(str2);if(!root)printf("str2 JSON格式错误:%s \r\n", cJSON_GetErrorPtr());else{printf("str2 JSON格式正确:\n%s\n",cJSON_Print(root));time_str = cJSON_GetObjectItem(root,"time")->valuestring;//time键值对printf("time:%s\n", time_str);loc_json = cJSON_GetObjectItem(root,"location");if(loc_json){name1_json = cJSON_GetArrayItem(loc_json,0);        //数组第0个元素str_tmp = cJSON_GetObjectItem(name1_json, "name")->valuestring;//name键对应的值printf("name1 is : %s \r\n", str_tmp);str_tmp = cJSON_GetObjectItem(name1_json, "address")->valuestring;//addr1键对应的值printf("addr1 is : %s \r\n", str_tmp);name2_json = cJSON_GetArrayItem(loc_json,1);       //数组第1个元素str_tmp = cJSON_GetObjectItem(name2_json, "name")->valuestring;printf("name2 is : %s \r\n", str_tmp);str_tmp = cJSON_GetObjectItem(name2_json, "address")->valuestring;printf("addr2 is : %s \r\n", str_tmp);}}cJSON_Delete(loc_json);
}

运行结果：

北京时间JSON数据解析

api地址：

http://api.k780.com:88/?app=life.time&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json

JSON字符串：

{"success": "1","result": {"timestamp": "1543922613","datetime_1": "2018-12-04 19:23:33","datetime_2": "2018年12月04日 19时23分33秒","week_1": "2","week_2": "星期二","week_3": "周二","week_4": "Tuesday"}
}                               

解析函数：

void Parse_BJ_Time(void)
{char bj_time_str[] = "{\"success\":\"1\",\"result\":{\"timestamp\":\"1542456793\",\"datetime_1\":\"2018-11-17 20:13:13\",\"datetime_2\":\"2018年11月17日 20时13分13秒\",\"week_1\":\"6\",\"week_2\":\"星期六\",\"week_3\":\"周六\",\"week_4\":\"Saturday\"}}";cJSON *root;cJSON *result_json;char *datetime, *week;root = cJSON_Parse(bj_time_str);if(root){printf("json格式正确:\n%s\n\n", cJSON_Print(root));result_json =  cJSON_GetObjectItem(root, "result");  //获取result键对应的值if(result_json){datetime = cJSON_GetObjectItem(result_json, "datetime_2")->valuestring;printf("北京时间: %s \r\n", datetime);week = cJSON_GetObjectItem(result_json, "week_2")->valuestring;printf("星期: %s \r\n", week);}}cJSON_Delete(root);cJSON_Delete(result_json);
}

运行结果：

心知天气JSON数据解析

JSON字符串：

{"results": [{"location": {"id": "WS10730EM8EV","name": "深圳","country": "CN","path": "深圳,深圳,广东,中国","timezone": "Asia/Shanghai","timezone_offset": "+08:00"},"daily": [{"date": "2018-11-18","text_day": "多云","code_day": "4","text_night": "多云","code_night": "4","high": "26","low": "20","precip": "","wind_direction": "无持续风向","wind_direction_degree": "","wind_speed": "10","wind_scale": "2"}, {"date": "2018-11-19","text_day": "小雨","code_day": "13","text_night": "小雨","code_night": "13","high": "25","low": "20","precip": "","wind_direction": "无持续风向","wind_direction_degree": "","wind_speed": "10","wind_scale": "2"}, {"date": "2018-11-20","text_day": "小雨","code_day": "13","text_night": "小雨","code_night": "13","high": "25","low": "21","precip": "","wind_direction": "无持续风向","wind_direction_degree": "","wind_speed": "10","wind_scale": "2"}],"last_update": "2018-11-18T11:00:00+08:00"}]
}

解析函数：

void parse_seniverse_weather(void)
{char weather_str[] ="{\"results\":[{\"location\":{\"id\":\"WS10730EM8EV\",\"name\":\"深圳\",\"country\":\"CN\",\"path\":\"深圳,深圳,广东,中国\",\"timezone\":\"Asia/Shanghai\",\"timezone_offset\":\"+08:00\"},\"daily\":[{\"date\":\"2018-11-18\",\"text_day\":\"多云\",\"code_day\":\"4\",\"text_night\":\"多云\",\"code_night\":\"4\",\"high\":\"26\",\"low\":\"20\",\"precip\":\"\",\"wind_direction\":\"无持续风向\",\"wind_direction_degree\":\"\",\"wind_speed\":\"10\",\"wind_scale\":\"2\"},{\"date\":\"2018-11-19\",\"text_day\":\"小雨\",\"code_day\":\"13\",\"text_night\":\"小雨\",\"code_night\":\"13\",\"high\":\"25\",\"low\":\"20\",\"precip\":\"\",\"wind_direction\":\"无持续风向\",\"wind_direction_degree\":\"\",\"wind_speed\":\"10\",\"wind_scale\":\"2\"},{\"date\":\"2018-11-20\",\"text_day\":\"小雨\",\"code_day\":\"13\",\"text_night\":\"小雨\",\"code_night\":\"13\",\"high\":\"25\",\"low\":\"21\",\"precip\":\"\",\"wind_direction\":\"无持续风向\",\"wind_direction_degree\":\"\",\"wind_speed\":\"10\",\"wind_scale\":\"2\"}],\"last_update\":\"2018-11-18T11:00:00+08:00\"}]}";cJSON *root;cJSON *results;cJSON *last_update;cJSON *loc_json, *daily_json;cJSON *forecast_json;char *loc_tmp, *weather_tmp, *update_tmp;int i = 0;root = cJSON_Parse((const char*)weather_str);if(root){
//        printf("JSON格式正确:\n%s\n\n",cJSON_Print(root));    //输出json字符串results = cJSON_GetObjectItem(root, "results");results = cJSON_GetArrayItem(results,0);if(results){loc_json = cJSON_GetObjectItem(results, "location");   //得到location键对应的值，是一个对象loc_tmp = cJSON_GetObjectItem(loc_json, "id") -> valuestring;printf("城市ID:%s\n",loc_tmp);loc_tmp = cJSON_GetObjectItem(loc_json, "name") -> valuestring;printf("城市名称:%s\n",loc_tmp);loc_tmp = cJSON_GetObjectItem(loc_json, "timezone") -> valuestring;printf("城市时区:%s\n\n",loc_tmp);daily_json = cJSON_GetObjectItem(results, "daily");if(daily_json){for(i = 0; i < 3; i++){forecast_json = cJSON_GetArrayItem(daily_json, i);weather_tmp = cJSON_GetObjectItem(forecast_json, "date") -> valuestring;printf("日期:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "code_day") -> valuestring;printf("白天天气代码:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "code_night") -> valuestring;printf("晚上天气代码:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "high") -> valuestring;printf("最高温度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "low") -> valuestring;printf("最低温度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "wind_direction_degree") -> valuestring;printf("风向角度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "wind_scale") -> valuestring;printf("风力:%s\r\n\n", weather_tmp);}}elseprintf("daily json格式错误\r\n");last_update = cJSON_GetObjectItem(results, "last_update");update_tmp = last_update->valuestring;if(last_update){printf("更新时间:%s\r\n", update_tmp);}}else{printf("results格式错误:%s\r\n", cJSON_GetErrorPtr());}}else{printf("JSON格式错误\r\n");}cJSON_Delete(root);cJSON_Delete(results);
}

运行结果：

和风天气数据解析

JSON字符串：

{"HeWeather6": [{"basic": {"cid": "CN101010700","location": "昌平","parent_city": "北京","admin_area": "北京","cnty": "中国","lat": "40.21808624","lon": "116.23590851","tz": "+8.00"},"update": {"loc": "2018-11-21 21:45","utc": "2018-11-21 13:45"},"status": "ok","daily_forecast": [{"cond_code_d": "100","cond_code_n": "100","cond_txt_d": "晴","cond_txt_n": "晴","date": "2018-11-21","hum": "21","mr": "16:02","ms": "04:27","pcpn": "0.0","pop": "0","pres": "1030","sr": "07:08","ss": "16:53","tmp_max": "9","tmp_min": "-3","uv_index": "5","vis": "10","wind_deg": "323","wind_dir": "西北风","wind_sc": "1-2","wind_spd": "4"}, {"cond_code_d": "100","cond_code_n": "101","cond_txt_d": "晴","cond_txt_n": "多云","date": "2018-11-22","hum": "21","mr": "16:36","ms": "05:33","pcpn": "0.0","pop": "0","pres": "1030","sr": "07:09","ss": "16:52","tmp_max": "8","tmp_min": "-4","uv_index": "3","vis": "20","wind_deg": "35","wind_dir": "东北风","wind_sc": "1-2","wind_spd": "5"}, {"cond_code_d": "101","cond_code_n": "100","cond_txt_d": "多云","cond_txt_n": "晴","date": "2018-11-23","hum": "23","mr": "17:15","ms": "06:41","pcpn": "0.0","pop": "16","pres": "1024","sr": "07:10","ss": "16:52","tmp_max": "7","tmp_min": "-2","uv_index": "2","vis": "20","wind_deg": "305","wind_dir": "西北风","wind_sc": "1-2","wind_spd": "3"}]}]
}

解析函数：

//解析和风天气，格式和心知天气非常像
void parse_heweather(void)
{char heweather_str[] = "{\"HeWeather6\":[{\"basic\":{\"cid\":\"CN101010700\",\"location\":\"昌平\",\"parent_city\":\"北京\",\"admin_area\":\"北京\",\"cnty\":\"中国\",\"lat\":\"40.21808624\",\"lon\":\"116.23590851\",\"tz\":\"+8.00\"},\"update\":{\"loc\":\"2018-11-21 21:45\",\"utc\":\"2018-11-21 13:45\"},\"status\":\"ok\",\"daily_forecast\":[{\"cond_code_d\":\"100\",\"cond_code_n\":\"100\",\"cond_txt_d\":\"晴\",\"cond_txt_n\":\"晴\",\"date\":\"2018-11-21\",\"hum\":\"21\",\"mr\":\"16:02\",\"ms\":\"04:27\",\"pcpn\":\"0.0\",\"pop\":\"0\",\"pres\":\"1030\",\"sr\":\"07:08\",\"ss\":\"16:53\",\"tmp_max\":\"9\",\"tmp_min\":\"-3\",\"uv_index\":\"5\",\"vis\":\"10\",\"wind_deg\":\"323\",\"wind_dir\":\"西北风\",\"wind_sc\":\"1-2\",\"wind_spd\":\"4\"},{\"cond_code_d\":\"100\",\"cond_code_n\":\"101\",\"cond_txt_d\":\"晴\",\"cond_txt_n\":\"多云\",\"date\":\"2018-11-22\",\"hum\":\"21\",\"mr\":\"16:36\",\"ms\":\"05:33\",\"pcpn\":\"0.0\",\"pop\":\"0\",\"pres\":\"1030\",\"sr\":\"07:09\",\"ss\":\"16:52\",\"tmp_max\":\"8\",\"tmp_min\":\"-4\",\"uv_index\":\"3\",\"vis\":\"20\",\"wind_deg\":\"35\",\"wind_dir\":\"东北风\",\"wind_sc\":\"1-2\",\"wind_spd\":\"5\"},{\"cond_code_d\":\"101\",\"cond_code_n\":\"100\",\"cond_txt_d\":\"多云\",\"cond_txt_n\":\"晴\",\"date\":\"2018-11-23\",\"hum\":\"23\",\"mr\":\"17:15\",\"ms\":\"06:41\",\"pcpn\":\"0.0\",\"pop\":\"16\",\"pres\":\"1024\",\"sr\":\"07:10\",\"ss\":\"16:52\",\"tmp_max\":\"7\",\"tmp_min\":\"-2\",\"uv_index\":\"2\",\"vis\":\"20\",\"wind_deg\":\"305\",\"wind_dir\":\"西北风\",\"wind_sc\":\"1-2\",\"wind_spd\":\"3\"}]}]}";cJSON *root;cJSON *results;cJSON *basic_json, *update_json, *forecast_json;cJSON *daily_json;int i = 0;char *basic_tmp, *update_tmp, *status_tmp, *weather_tmp;root = cJSON_Parse(heweather_str);if(root){results = cJSON_GetObjectItem(root, "HeWeather6");      //HeWeather键对应的值，是一个数组results = cJSON_GetArrayItem(results,0);if(results){basic_json = cJSON_GetObjectItem(results, "basic");if(basic_json){basic_tmp = cJSON_GetObjectItem(basic_json, "cid") -> valuestring;printf("城市ID:%s\n",basic_tmp);basic_tmp = cJSON_GetObjectItem(basic_json, "location") -> valuestring;printf("县级市:%s\n",basic_tmp);basic_tmp = cJSON_GetObjectItem(basic_json, "parent_city") -> valuestring;printf("地级市:%s\n",basic_tmp);basic_tmp = cJSON_GetObjectItem(basic_json, "admin_area") -> valuestring;printf("所属省:%s\n",basic_tmp);basic_tmp = cJSON_GetObjectItem(basic_json, "lat") -> valuestring;printf("纬度:%s\n",basic_tmp);basic_tmp = cJSON_GetObjectItem(basic_json, "lon") -> valuestring;printf("经度:%s\n\n",basic_tmp);}update_json = cJSON_GetObjectItem(results, "update");if(update_json){update_tmp = cJSON_GetObjectItem(update_json, "loc") -> valuestring;printf("更新时间:%s(所在地时间)\n", update_tmp);update_tmp = cJSON_GetObjectItem(update_json, "utc") -> valuestring;printf("更新时间:%s(世界时间)\n\n", update_tmp);}status_tmp = cJSON_GetObjectItem(results, "status") -> valuestring;printf("解析状态:%s\n\n", status_tmp);daily_json = cJSON_GetObjectItem(results, "daily_forecast");if(daily_json){for(i = 0; i < 3; i++){forecast_json = cJSON_GetArrayItem(daily_json, i);weather_tmp = cJSON_GetObjectItem(forecast_json, "date") -> valuestring;printf("日期:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "cond_txt_d") -> valuestring;printf("白天天气:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "cond_txt_n") -> valuestring;printf("晚上天气:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "tmp_max") -> valuestring;printf("最高温度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "tmp_min") -> valuestring;printf("最低温度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "wind_deg") -> valuestring;printf("风向角度:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "wind_dir") -> valuestring;printf("风向:%s\r\n", weather_tmp);weather_tmp = cJSON_GetObjectItem(forecast_json, "wind_sc") -> valuestring;printf("风力:%s\r\n\n", weather_tmp);}}}}cJSON_Delete(root);cJSON_Delete(results);cJSON_Delete(basic_json);cJSON_Delete(update_json);cJSON_Delete(forecast_json);cJSON_Delete(daily_json);
}

运行结果：

源码下载及实用的API地址：

• 本项目CodeBlock工程源码下载：MyJSON

• 在线JSON格式校验工具：bejson

• 免费的天气api接口：天气API

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