jsoncpp封装和解析字符串、数字、布尔值和数组

使用jsoncpp进行字符串、数字、布尔值和数组的封装与解析。

1）下载jsoncpp的代码库 百度网盘地址 ：http://pan.baidu.com/s/1ntqQhIT

2）解压缩文件 jsoncpp.rar

unzip jsoncpp.rar

3）修改jsoncpp/src/main.cpp文件

vim src/main.cpp

  1 #include <string>

  2 #include <json/json.h>

  3 #include "stdio.h"

  4 

  5 int ReadJson(const std::string &);

  6 std::string writeJson();

  7 

  8 int main(int argc, char** argv)

  9 {

 10     using namespace std;

 11 

 12     std::string strMsg;

 13 

 14     cout<<"--------------------------------"<<endl;

 15     strMsg = writeJson();

 16     cout<< "json write : " << endl << strMsg << endl;

 17     cout<<"--------------------------------"<<endl;

 18     cout<< "json read :" << endl;

 19     ReadJson(strMsg);

 20     cout<<"--------------------------------"<<endl;

 21 

 22     return 0;

 23 }

 24 

 25 int ReadJson(const std::string & strValue) 

 26 {

 27     using namespace std;

 28 

 29     Json::Reader reader;

 30     Json::Value value;

 31 

 32     if (reader.parse(strValue, value))

 33     {

 34         //解析json中的对象

 35         string out = value["name"].asString();

 36         cout << "name : "   << out << endl;

 37         cout << "number : " << value["number"].asInt() << endl;

 38         cout << "value : "  << value["value"].asBool() << endl;

 39         cout << "no such num : " << value["haha"].asInt() << endl;

 40         cout << "no such str : " << value["hehe"].asString() << endl;

 41 

 42         //解析数组对象

 43         const Json::Value arrayNum = value["arrnum"];

 44         for (unsigned int i = 0; i < arrayNum.size(); i++)

 45         {

 46             cout << "arrnum[" << i << "] = " << arrayNum[i];

 47         }

 48         //解析对象数组对象

 49         Json::Value arrayObj = value["array"];

 50         cout << "array size = " << arrayObj.size() << endl;

 51         for(unsigned int i = 0; i < arrayObj.size(); i++)

 52         {

 53             cout << arrayObj[i];

 54         }

 55         //从对象数组中找到想要的对象

 56         for(unsigned int i = 0; i < arrayObj.size(); i++)

 57         {

 58             if (arrayObj[i].isMember("string")) 

 59             {

 60                 out = arrayObj[i]["string"].asString();

 61                 std::cout << "string : " << out << std::endl;

 62             }

 63         }

 64     }

 65 

 66     return 0;

 67 }

 68 

 69 std::string writeJson() 

 70 {

 71     using namespace std;

 72 

 73     Json::Value root;

 74     Json::Value arrayObj;

 75     Json::Value item;

 76     Json::Value iNum;

 77 

 78     item["string"]    = "this is a string";

 79     item["number"]    = 999;

 80     item["aaaaaa"]    = "bbbbbb";

 81     arrayObj.append(item);

 82 

 83     //直接对jsoncpp对象以数字索引作为下标进行赋值，则自动作为数组

 84     iNum[1] = 1;

 85     iNum[2] = 2;

 86     iNum[3] = 3;

 87     iNum[4] = 4;

 88     iNum[5] = 5;

 89     iNum[6] = 6;

 90 

 91     //增加对象数组

 92     root["array"]    = arrayObj;

 93     //增加字符串

 94     root["name"]    = "json";

 95     //增加数字

 96     root["number"]    = 666;

 97     //增加布尔变量

 98     root["value"]    = true;

 99     //增加数字数组

100     root["arrnum"]    = iNum;

101 

102     root.toStyledString();

103     string out = root.toStyledString();

104 

105     return out;

106 }

4）在目录jsoncpp/ 下执行make命令

jsoncpp$ make

mkdir -p objs/src/json;  mkdir -p objs/src;

g++ -c -Wall -Werror -g -I include src/json/json_reader.cpp -o objs/src/json/json_reader.o

g++ -c -Wall -Werror -g -I include src/json/json_value.cpp -o objs/src/json/json_value.o

g++ -c -Wall -Werror -g -I include src/json/json_writer.cpp -o objs/src/json/json_writer.o

g++ -c -Wall -Werror -g -I include src/main.cpp -o objs/src/main.o

g++  objs/src/json/json_reader.o objs/src/json/json_value.o objs/src/json/json_writer.o objs/src/main.o -o main

5)运行jsoncpp/下的main文件

./main

6)运行结果如下

fengbo: jsoncpp$ ./main 

--------------------------------

json write : 

{

   "array" : [

      {

         "aaaaaa" : "bbbbbb",

         "number" : 999,

         "string" : "this is a string"

      }

   ],

   "arrnum" : [ null, 1, 2, 3, 4, 5, 6 ],

   "name" : "json",

   "number" : 666,

   "value" : true

}



--------------------------------

json read :

name : json

number : 666

value : 1

no such num : 0

no such str : 

arrnum[0] = null

arrnum[1] = 1

arrnum[2] = 2

arrnum[3] = 3

arrnum[4] = 4

arrnum[5] = 5

arrnum[6] = 6

array size = 1



{

    "aaaaaa" : "bbbbbb",

    "number" : 999,

    "string" : "this is a string"

}

string : this is a string

--------------------------------

 

作者：风波

mail : [email protected]