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
3）修改jsoncpp/src/main.cpp文件
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
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 : fengbohello@qq.com
