因为工作需要，需要对一段嵌套的json进行解析。其中我使用的开发语言是C++。

由于rapidjson的解析效率高效，所以今天研究了下RapidJson，下面是一段我用RapidJson解析的一段具有嵌套数组的json文本代码。

JSON文本如下：

{

"Info": [

{

"lots": 10,

"order_algorithm": "01",

"buy_close": 9000,

"spread_shift": 0,

"position_b_sell": 0,

"position_a_buy_today": 0,

"position_a_buy_yesterday": 0,

"sell_open": -9000,

"list_instrument_id": [

"rb1705",

"rb1701"

],

"position_b_buy_today": 0,

"buy_open": -9000,

"position_a_sell_yesterday": 0,

"strategy_id": "02",

"position_b_buy": 0,

"a_wait_price_tick": 1,

"trade_model": "boll_reversion",

"b_wait_price_tick": 0,

"sell_close": 9000,

"only_close": 0,

"order_action_limit": 400,

"is_active": 1,

"lots_batch": 1,

"position_a_sell": 0,

"position_b_buy_yesterday": 0,

"user_id": "063802",

"position_a_buy": 0,

"trader_id": "1601",

"position_a_sell_today": 0,

"stop_loss": 0,

"position_b_sell_today": 0,

"position_b_sell_yesterday": 0,

"on_off": 0

},

{

"lots": 10,

"order_algorithm": "01",

"buy_close": 9000,

"spread_shift": 0,

"position_b_sell": 0,

"position_a_buy_today": 0,

"position_a_buy_yesterday": 0,

"sell_open": -9000,

"list_instrument_id": [

"ni1705",

"ni1701"

],

"position_b_buy_today": 0,

"buy_open": -9000,

"position_a_sell_yesterday": 0,

"strategy_id": "01",

"position_b_buy": 0,

"a_wait_price_tick": 1,

"trade_model": "boll_reversion",

"b_wait_price_tick": 0,

"sell_close": 9000,

"only_close": 0,

"order_action_limit": 400,

"is_active": 1,

"lots_batch": 1,

"position_a_sell": 0,

"position_b_buy_yesterday": 0,

"user_id": "063802",

"position_a_buy": 0,

"trader_id": "1601",

"position_a_sell_today": 0,

"stop_loss": 0,

"position_b_sell_today": 0,

"position_b_sell_yesterday": 0,

"on_off": 0

}

],

"MsgSendFlag": 0,

"MsgErrorReason": "ID or password error",

"MsgRef": 1,

"MsgType": 3,

"MsgResult": 0

}

解析其格式的C++代码如下，我只解析关键部分，其余读者可以自行添加。

#include "rapidjson/document.h"

#include "rapidjson/writer.h"

#include "rapidjson/stringbuffer.h"

#include

using namespace rapidjson;

int main() {

// 1. Parse a JSON string into DOM.

const char* json ="{\"Info\":[{\"lots\":10,\"order_algorithm\":\"01\",\"buy_close\":9000,\"spread_shift\":0,\"position_b_sell\":0,\"position_a_buy_today\":0,\"position_a_buy_yesterday\":0,\"sell_open\":-9000,\"list_instrument_id\":[\"rb1705\",\"rb1701\"],\"position_b_buy_today\":0,\"buy_open\":-9000,\"position_a_sell_yesterday\":0,\"strategy_id\":\"02\",\"position_b_buy\":0,\"a_wait_price_tick\":1,\"trade_model\":\"boll_reversion\",\"b_wait_price_tick\":0,\"sell_close\":9000,\"only_close\":0,\"order_action_limit\":400,\"is_active\":1,\"lots_batch\":1,\"position_a_sell\":0,\"position_b_buy_yesterday\":0,\"user_id\":\"063802\",\"position_a_buy\":0,\"trader_id\":\"1601\",\"position_a_sell_today\":0,\"stop_loss\":0,\"position_b_sell_today\":0,\"position_b_sell_yesterday\":0,\"on_off\":0},{\"lots\":20,\"order_algorithm\":\"02\",\"buy_close\":9000,\"spread_shift\":0,\"position_b_sell\":0,\"position_a_buy_today\":0,\"position_a_buy_yesterday\":0,\"sell_open\":-9000,\"list_instrument_id\":[\"ni1705\",\"ni1701\"],\"position_b_buy_today\":0,\"buy_open\":-9000,\"position_a_sell_yesterday\":0,\"strategy_id\":\"01\",\"position_b_buy\":0,\"a_wait_price_tick\":1,\"trade_model\":\"boll_reversion\",\"b_wait_price_tick\":0,\"sell_close\":9000,\"only_close\":0,\"order_action_limit\":400,\"is_active\":1,\"lots_batch\":1,\"position_a_sell\":0,\"position_b_buy_yesterday\":0,\"user_id\":\"063802\",\"position_a_buy\":0,\"trader_id\":\"1601\",\"position_a_sell_today\":0,\"stop_loss\":0,\"position_b_sell_today\":0,\"position_b_sell_yesterday\":0,\"on_off\":0}],\"MsgSendFlag\":0,\"MsgErrorReason\":\"IDorpassworderror\",\"MsgRef\":1,\"MsgType\":3,\"MsgResult\":0}";

//std::cout << json << std::endl;

//std::cout << "\n" << std::endl;

std::cout << "|==================|" << std::endl;

std::cout << "||rapidjson output||" << std::endl;

std::cout << "|==================|" << std::endl;

Document doc;

doc.Parse(json);

// 2. Modify it by DOM.

Value& s = doc["MsgSendFlag"];

s.SetInt(s.GetInt() + 1);

Value& infoArray = doc["Info"];

if (infoArray.IsArray()) {

for (int i = 0; i < infoArray.Size(); i++) {

const Value& object = infoArray[i];

int lots = object["lots"].GetInt();

std::string order_algorithm = object["order_algorithm"].GetString();

std::cout << "int lots = " << lots << std::endl;

std::cout << "string order_algorithm = " << order_algorithm << std::endl;

const Value& info_object = object["list_instrument_id"];

if (info_object.IsArray()) {

for (int j = 0; j < info_object.Size(); j++) {

std::string instrument = info_object[j].GetString();

std::cout << "instrument[" << j << "] = " << instrument << std::endl;

}

}

}

}

// 3. Stringify the DOM

StringBuffer buffer;

Writer writer(buffer);

doc.Accept(writer);

std::cout << buffer.GetString() << std::endl;

return 0;

}

运行结果如下：

参考：http://stackoverflow.com/questions/23170718/rapidjson-get-a-value-inside-an-array-of-another-array

http://www.cnblogs.com/ziyouchutuwenwu/p/3790322.html

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