String a = {"id":"cszb1","value":"999"},{"id":"cszbzd2","value":"999"},转json

这里提供一种C++的方法将字符串转换为JSON格式：

#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <iomanip>
#include <cstring>
#include <algorithm>
#include <iterator>
#include <map>

using namespace std;

string escape(string const& s) {
    ostringstream o;
    for (auto c : s) {
        switch (c) {
            case '"': o << "\\\""; break;
            case '\\': o << "\\\\"; break;
            case '\b': o << "\\b"; break;
            case '\f': o << "\\f"; break;
            case '\n': o << "\\n"; break;
            case '\r': o << "\\r"; break;
            case '\t': o << "\\t"; break;
            default:
                if ('\x00' <= c && c <= '\x1f') {
                    o << "\\u" << hex << setw(4) << setfill('0') << static_cast<int>(c);
                } else {
                    o << c;
                }
        }
    }
    return o.str();
}

string to_json(string const& s) {
    return '"' + escape(s) + '"';
}

string to_json(int n) {
    return to_string(n);
}

string to_json(double d) {
    ostringstream o;
    o << d;
    return o.str();
}

template <typename T>
string to_json(vector<T> const& v) {
    ostringstream o;
    o << '[';
    bool first = true;
    for (auto const& e : v) {
        if (!first) {
            o << ',';
        }
        first = false;
        o << to_json(e);
    }
    o << ']';
    return o.str();
}

template <typename K, typename V>
string to_json(map<K, V> const& m) {
    ostringstream o;
    o << '{';
    bool first = true;
    for (auto const& p : m) {
        if (!first) {
            o << ',';
        }
        first = false;
        o << to_json(p.first) << ':' << to_json(p.second);
    }
    o << '}';
    return o.str();
}

int main() {
    string a = R"([{"id":"cszb1","value":"999"},{"id":"cszbzd2","value":"999"}])";
    vector<map<string, string>> v;
    size_t i = 0;
    while (i < a.size()) {
        size_t j = a.find_first_of("{[", i);
        if (j == string::npos) {
            break;
        }
        size_t k = a.find_first_of("}]", j);
        if (k == string::npos) {
            break;
        }
        string s = a.substr(j, k - j + 1);
        map<string, string> m;
        size_t l = 0;
        while (l < s.size()) {
            size_t p = s.find_first_of(":\"", l);
            if (p == string::npos) {
                break;
            }
            size_t q = s.find_first_of("\",}", p + 1);
            if (q == string::npos) {
                break;
            }
            string key = s.substr(l + 1, p - l - 2);
            string value = s.substr(p + 2, q - p - 2);
            m[key] = value;
            l = q + 1;
        }
        v.push_back(m);
        i = k + 1;
    }
    cout << to_json(v) << endl;
    return 0;
}

这个程序将字符串a解析为一个vector，其中每个元素都是一个map，map的key是字符串"id"和"value"，value是字符串"999"。然后，使用to_json函数将vector转换为JSON格式的字符串。