jsoncpp学习

// MyJsonTest.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <fstream>
#include <cassert>
#include "json/json.h"

using namespace std;
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void test1() {
    Json::Value root;
    Json::FastWriter writer;
    Json::Value person;

    person["FileName"] = "test1";
    person["fileLength"] = ""; // 4G以内文件
    person.removeMember("fileLength");
    root.append(person);
    person["FileName"] = "test2";
    person["fileLength"] = ""; // 4G以内文件
    root.append(person);
    person["FileName"] = "test3";
    person["fileLength"] = ""; // 4G以内文件
    root.append(person);

    std::string json_file = writer.write(root);

    ofstream ofs;
    ofs.open("test1.json", ios::trunc);
    assert(ofs.is_open());
    ofs << json_file;
    ofs.close();
}

int test2() {
    Json::Reader pJsonParser;;
    string strJson = "{\"name\":\"tom\",\"sex\":\"男\",\"age\":\"24\",\"friends\":[{\"name\":\"chen\",\"sex\":\"男\"},{\"name\":\"li\",\"sex\":\"女\"}]}";
    Json::Value tempVal;

    if (!pJsonParser.parse(strJson, tempVal))
    {
        cout << "parse error" << endl;
        return -;
    }

    string name = tempVal["name"].asString();
    string sex = tempVal["sex"].asString();
    string age = tempVal["age"].asString();

    Json::Value friends = tempVal["friends"];
    for (int i = ; i < friends.size(); i++) {
        cout << friends[i]["name"].asString() << endl;
    }
    cout << "name = " << name << "    age = " << age << "    sex = " << sex  << endl;

    return ;
}

void test3() {
        Json::Value root;
        Json::Value arrayObj;
        Json::Value item;
        Json::FastWriter writer;
        for (int i = ; i<; i++)
        {
            item["key"] = i;
            arrayObj.append(item); //数组项添加
        }
        root["key1"] = "value1";
        root["key2"] = "value2";
        root["key3"] = 0x100;
        root["key4"] = true;
        root["key5"] = "中国人";
        item = root["key5"];
        root["array"] = arrayObj;
        std::cout << root.toStyledString();
        std::cout << writer.write(root);
}

void test4() {
    char* config_doc = "{\"encoding\" : \"UTF-8\",\"plug-ins\" : [\"python\",\"c++\",\"ruby\"],\"indent\" : { \"length\" : 3, \"use_space\" : true }}";

    Json::Value root;   // will contains the root value after parsing.
    Json::Reader reader;
    bool parsingSuccessful = reader.parse(config_doc, root);
    if (!parsingSuccessful)
    {
        // report to the user the failure and their locations in the document.
        std::cout << "Failed to parse configuration\n";
        return;
    }

    // Get the value of the member of root named 'encoding', return 'UTF-8' if there is no
    // such member.
    std::string encoding = root.get("encoding", "UTF-8").asString();
    // Get the value of the member of root named 'encoding', return a 'null' value if
    // there is no such member.
    const Json::Value plugins = root["plug-ins"];
    for (int index = ; index < plugins.size(); ++index)  // Iterates over the sequence elements.
        std::cout << plugins[index].asString() << std::endl;

    std::cout << root["indent"].get("length", ).asInt() << std::endl;

    std::cout << root["indent"].get("use_space", true).asBool() << std::endl;;

    // ...
    // At application shutdown to make the new configuration document:
    // Since Json::Value has implicit constructor for all value types, it is not
    // necessary to explicitly construct the Json::Value object:
    //root["encoding"] = getCurrentEncoding();
    //root["indent"]["length"] = getCurrentIndentLength();
    //root["indent"]["use_space"] = getCurrentIndentUseSpace();

    Json::StyledWriter writer;
    // Make a new JSON document for the configuration. Preserve original comments.
    std::string outputConfig = writer.write(root);

    // You can also use streams.  This will put the contents of any JSON
    // stream at a particular sub-value, if you'd like.
    //std::cin >> root["subtree"];

    // And you can write to a stream, using the StyledWriter automatically.
    std::cout << root;
}

void test5() {
    Json::Reader reader;
    Json::Value root;
    Json::StyledStreamWriter writer;
    std::string text = "{ \"first\": \"James\", \"last\": \"Bond\", \"nums\": [0, 0, 7] }";
    std::ofstream outFile;

    // Parse JSON and print errors if needed
    if (!reader.parse(text, root)) {
        std::cout << reader.getFormatedErrorMessages();
        exit();
    }
    else {

        // Read and modify the json data
        std::cout << "Size: " << root.size() << std::endl;
        std::cout << "Contains nums? " << root.isMember("nums") << std::endl;
        root["first"] = "Jimmy";
        root["middle"] = "Danger";

        // Write the output to a file
        outFile.open("output.json");
        writer.write(outFile, root);
        outFile.close();
    }
}

int main()
{
    test5();

    return ;
}

考虑在打包时候使用json记录打包文件信息
但是json似乎不支持64位数据 那么大于4G的文件长度怎么记录？这是个问题

代码见

http://www.oschina.net/code/snippet_614253_56645