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网络API接口的使用

分类: 文章 • 2024-02-25 15:27:57



                                                网络API接口的使用

一：先介绍一下什么是网络API接口
    网络API接口就是各种大公司对外提供的一种各种信息和数据获取的接口像百度,腾讯,阿里巴巴等都提供这种接口,一些小公司和个人就可以通过这些接口获取各种信息,如城市天气信息,生成二维码,地图信息,手机号码归属地,摄像头,卫星定位等。这些小公司就可以通过付费的方式使用这些接口,从而做出像天气预报查询，地图导航等一系列的APP。对于我们学习使用来讲这些接口大部分都有免费使用次数，足够我们学习使用

二：我在这里介绍一下两种API接口
1: k780.com     这个网站提供的接口可免费使用
 进入网页看到下图
 网络API接口的使用


 点击上面的数据接口可以看到许多接口

网络API接口的使用

2： 百度API接口
 可以先注册一个百度账号，百度API同样有免费使用次数，足够学习使用。

使用方法：
 我就以天气预报解析作为示例
 我们从k780.com 获取天气预报接口如下
 http://api.k780.com:88/app=weather.future&weaid=1&&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json
 注：
      1：接口中weaid=后面接的就是你想查询的城市名称，比如我所在的城市南昌
      2：由于我们在程序中获取这条接口命令传回来的信息是直接输入在Linux系统
      的命令行上，而&是特殊字符，所以要用单引号引起来
      3：用Linux命令curl来运行这条接口命令 
      4：在命令的结尾处需要将返回的信息存放在文件中，可在结尾将信息定向到一
      个文件中例如：> 123.txt
 综合上述几点注意，可得命令为：
 curl    http://api.k780.com:88/?app=weather.future'&'weaid=南昌'&&'appkey=10003'&'sign=b59bc3ef6191eb9f747dd4e83c99f2a4'&'
 format=json > 123.txt


 三：在C语言程序中如何使用：
 可用C语言system函数来执行命令。
 
四：获取的天气信息如下：(格式为json格式)

{"success":"1","result":[{"weaid":"237","days":"2018-02-05","week":"星期一",
"cityno":"nanchang","citynm":"南昌","cityid":"101240101","temperature":"7℃/
-1℃","humidity":"0%/0%","weather":"晴","weather_icon":"http://api.k780.com/
upload/weather/d/0.gif","weather_icon1":"http://api.k780.com/upload/weather/
n/0.gif","wind":"东北风","winp":"<3级","temp_high":"7","temp_low":"-1","humi
_high":"0","humi_low":"0","weatid":"1","weatid1":"1","windid":"13","winpid":
"395"},{"weaid":"237","days":"2018-02-06","week":"星期二","cityno":"nanchang
","citynm":"南昌","cityid":"101240101","temperature":"8℃/1℃","humidity":"0
%/0%","weather":"晴转多云","weather_icon":"http://api.k780.com/upload/weathe
r/d/0.gif","weather_icon1":"http://api.k780.com/upload/weather/n/1.gif","win
d":"东北风","winp":"<3级","temp_high":"8","temp_low":"1","humi_high":"0","hu
mi_low":"0","weatid":"1","weatid1":"2","windid":"13","winpid":"395"},{"weaid
":"237","days":"2018-02-07","week":"星期三","cityno":"nanchang","citynm":"南
昌","cityid":"101240101","temperature":"10℃/2℃","humidity":"0%/0%","weathe
r":"多云","weather_icon":"http://api.k780.com/upload/weather/d/1.gif","weath
er_icon1":"http://api.k780.com/upload/weather/n/1.gif","wind":"东北风转北风"
,"winp":"<3级","temp_high":"10","temp_low":"2","humi_high":"0","humi_low":"0
","weatid":"2","weatid1":"2","windid":"25","winpid":"395"},{"weaid":"237","d
ays":"2018-02-08","week":"星期四","cityno":"nanchang","citynm":"南昌","cityi
d":"101240101","temperature":"11℃/4℃","humidity":"0%/0%","weather":"多云转
阴","weather_icon":"http://api.k780.com/upload/weather/d/1.gif","weather_icon
1":"http://api.k780.com/upload/weather/n/2.gif","wind":"东北风转北风","winp":
"<3级","temp_high":"11","temp_low":"4","humi_high":"0","humi_low":"0","weatid
":"2","weatid1":"3","windid":"25","winpid":"395"},{"weaid":"237","days":"2018
-02-09","week":"星期五","cityno":"nanchang","citynm":"南昌","cityid":"1012401
01","temperature":"6℃/5℃","humidity":"0%/0%","weather":"小雨","weather_icon
":"http://api.k780.com/upload/weather/d/7.gif","weather_icon1":"http://api.k7
80.com/upload/weather/n/7.gif","wind":"北风","winp":"<3级","temp_high":"6","t
emp_low":"5","humi_high":"0","humi_low":"0","weatid":"8","weatid1":"8","windi
d":"20","winpid":"395"},{"weaid":"237","days":"2018-02-10","week":"星期六","c
ityno":"nanchang","citynm":"南昌","cityid":"101240101","temperature":"10℃/2℃
","humidity":"0%/0%","weather":"阴转多云","weather_icon":"http://api.k780.com/
upload/weather/d/2.gif","weather_icon1":"http://api.k780.com/upload/weather/n/
1.gif","wind":"北风","winp":"<3级","temp_high":"10","temp_low":"2","humi_high"
:"0","humi_low":"0","weatid":"3","weatid1":"2","windid":"20","winpid":"395"},{
"weaid":"237","days":"2018-02-11","week":"星期日","cityno":"nanchang","citynm"
:"南昌","cityid":"101240101","temperature":"10℃/3℃","humidity":"0%/0%","weat
her":"多云转阴","weather_icon":"http://api.k780.com/upload/weather/d/1.gif","w
eather_icon1":"http://api.k780.com/upload/weather/n/2.gif","wind":"北风转无持续
风向","winp":"<3级","temp_high":"10","temp_low":"3","humi_high":"0","humi_low":
"0","weatid":"2","weatid1":"3","windid":"126","winpid":"395"}]}

注：获取到上述信息后，我们所要做的工作就是用C语言代码将信息解析出来

五：下面附上我自己的代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define WEEK_INFO_NUM   14
static char *str1="curl http://api.k780.com:88/?app=weather.future'&'weaid=";
static char *str2="'&&'appkey=10003'&'sign=b59bc3ef6191eb9f747dd4e83c99f2a4'&'format=json >wea.txt";
//定义一个保存天气信息的结构体
typedef struct _tag_Weather_Info
{
 char date[11];//日期
 char week[10];//星期
 char addr_pinyin[20];//地址拼音
 char addr_name[20];//地址中文
 char city_id[20];//城市id
 char temperature[10];//温度
 char humidity[10];//湿度
 char weather[20];//气候
 char wind[20];//风向
 char winp[10];//风力
 char temp_high[5];//最高气温
 char temp_low[5];//最低气温
 char humi_high[5];//最高湿度
 char humi_low[5];//最低湿度
}Wea_Info;
Wea_Info weather_info[14];//用于存放7天的天气信息
char *wea_flag[14]={"days","week","cityno","citynm","cityid","temperature",\
"humidity","weather","wind","winp","temp_high","temp_low","humi_high","humi_low"};
char buf[14][20];//定义一个存放信息的缓冲区

/*
 函数名称:move_to_info
 函数功能：将字符串移动到要提取的信息位置
 参数：char *str--字符串
 返回值：char *--移动后的字符串
 */
char *move_to_info(char *str)
{
 while(1)
 {
  if(*str==':')
   break;
  str++;
 }
 str+=2;
 return str;
}

/*
 函数名称:Get_Info
 函数功能：获取天气的单个信息
 参数：char *src--存放天气信息的字符串 int flag--要提取的信息编号 
 返回值：char *--提取完一次的字符串
 */
char *Get_Info(char *src,int flag)
{
 int i=0;
 while(1)
 {
  if(*src=='"')
   break;
  else
  {
   buf[flag][i++]=*src;
   src++;
  }
 }
 buf[flag][i]='\0';
 return src;
}

/*
 函数名称:Get_Weather_Info
 函数功能：获取天气信息
 参数：char *src_info--存放天气信息的字符串
 返回值：char *--提取完一次的字符串
 */
char *Get_Weather_Info(char *src_info,int num)
{
 int i=0;
 char *temp=NULL;
 for(i=0;i<WEEK_INFO_NUM;i++)
 {
  temp=strstr(src_info,wea_flag[i]);
  temp=move_to_info(temp);
  temp=Get_Info(temp,i);
 }
 i=0;
 //将信息放入结构体
 strcpy(weather_info[num].date,buf[i++]);
 strcpy(weather_info[num].week,buf[i++]);
 strcpy(weather_info[num].addr_pinyin,buf[i++]);
 strcpy(weather_info[num].addr_name,buf[i++]);
 strcpy(weather_info[num].city_id,buf[i++]);
 strcpy(weather_info[num].temperature,buf[i++]);
 strcpy(weather_info[num].humidity,buf[i++]);
 strcpy(weather_info[num].weather,buf[i++]);
 strcpy(weather_info[num].wind,buf[i++]);
 strcpy(weather_info[num].winp,buf[i++]);
 strcpy(weather_info[num].temp_high,buf[i++]);
 strcpy(weather_info[num].temp_low,buf[i++]);
 strcpy(weather_info[num].humi_high,buf[i++]);
 strcpy(weather_info[num].humi_low,buf[i++]);
 return temp;
}

/*
 函数名称:Print_Weather_Info
 函数功能：打印天气信息
 参数：int num--天数编号
 返回值：void
 */
void Print_Weather_Info(int num)
{
 printf("日期:%s\n",weather_info[num].date);
 printf("星期:%s\n",weather_info[num].week);
 printf("地址拼音:%s\n",weather_info[num].addr_pinyin);
 printf("地址中文:%s\n",weather_info[num].addr_name);
 printf("城市ID:%s\n",weather_info[num].city_id);
 printf("温度:%s\n",weather_info[num].temperature);
 printf("湿度:%s\n",weather_info[num].humidity);
 printf("气候:%s\n",weather_info[num].weather);
 printf("风向:%s\n",weather_info[num].wind);
 printf("风力:%s\n",weather_info[num].winp);
 printf("最高气温:%s\n",weather_info[num].temp_high);
 printf("最低气温:%s\n",weather_info[num].temp_low);
 printf("最高湿度:%s\n",weather_info[num].humi_high);
 printf("最低湿度:%s\n",weather_info[num].humi_low);
}
int main(int argc,char **argv)
{
 if(argc!=2)
 {
  printf("传参格式:./a.out <城市名>\n");
  exit(-1);
 }

 //拼接命令行字符串
 char *ptr=malloc(strlen(str1)+strlen(str2)+strlen(argv[1])+1);
 strcpy(ptr,str1);
 strcat(ptr,argv[1]);
 strcat(ptr,str2);

 //获取天气信息并将信息存放到123.txt
 system(ptr);
 FILE *fpr=fopen("wea.txt","rb");
 if(fpr==NULL)
 {
  printf("打开文件失败!\n");
  exit(-1);
 }
 //利用stat获取文件大小
 struct stat stat_buf;
 stat("wea.txt", &stat_buf);
 char *src=malloc(stat_buf.st_size);
 fread(src,1,stat_buf.st_size,fpr);
 fclose(fpr);
 int i=0;
 char *temp=src;
 for(i=0;i<7;i++)
 {
  memset(buf,0,sizeof(buf));
  temp=Get_Weather_Info(temp,i);
 }
 for(i=0;i<7;i++)
 {
  Print_Weather_Info(i);
  printf("\n");
 }
 return 0;
}

六：实际在解析过程中有两种方法可以解析，一种就是上面的自己找规律将信息解析出来，还有一种是通过cjson库来解析数据，这方面的知识可以到网上搜索一下，如果学会了cjson的使用，那解析数据就不用像上面一样那么麻烦。









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