应用boost库serialize标准库里的map

需求，最近做ios程序，需要将用户密码和帐号保存到本地磁盘，而用用户不止一个，想到boost库里的serialization比较适合，用户就用标准库里的map来保存，也就是std::map<std::string, std::string>，代码如下：

UserInfo.h:

//
// UserInfo.h
// app1
//
// Created by xp y on 12-8-23.
// Copyright (c) 2012年 xp y. All rights reserved.
//

#ifndef __app1__UserInfo__
#define __app1__UserInfo__
#import <map>
#import <string>
#import <fstream>
#import <boost/archive/binary_iarchive.hpp>
#import <boost/archive/binary_oarchive.hpp>
#import <boost/serialization/map.hpp>
#include <iostream>

// use this to ease the archive selection
typedef boost::archive::binary_iarchive iarchive;
typedef boost::archive::binary_oarchive oarchive;

class UserInfo
{

    friend class boost::serialization::access;

    protected :

    template <class Archive>
    void serialize(Archive& ar, const unsigned int   /* file_version */ );

    public :

    std::map<std::string, std::string> users;
    void setData();
    void showData();
    static void saveData(const std::map<std::string, std::string>& obj, std::string fileName)
    {
        std::ofstream ofs(fileName.c_str());
        oarchive oa(ofs);
        oa << obj;
    }

    static void loadData(std::map<std::string, std::string>& obj, std::string fileName)
    {
        std::ifstream ifs(fileName.c_str());
        iarchive ia(ifs);
        ia >> obj;
    }

    UserInfo();
    virtual ~UserInfo();
};

#endif /* defined(__app1__UserInfo__) */

UserInfo.mm:

#include "UserInfo.h"
#import <map>
#import <string>

template <class Archive>
void UserInfo::serialize(Archive& ar, const unsigned int   /* file_version */ )
{
    ar & users;
}

void UserInfo::setData() {

    users["aa"] = "hello";
    users["bb"] = "good";
}

void UserInfo::showData() {
    std::map<std::string, std::string>::iterator it = users.begin();
    std::cout << it->first << ":" << it->second << "\n";
    ++it;
    std::cout << it->first << ":" << it->second << "\n";
}

调用代码：

UserInfo u,u2;
u.mInt = 3 ;
u.setData();

UserInfo::saveData(u.users, "/Users/leejinchen/Downloads/output.txt");
UserInfo::loadData(u2.users, "/Users/leejinchen/Downloads/output.txt");
u2.showData();

输出：

aa:hello
bb:good

注意一定要包含

#import <boost/serialization/map.hpp>，否则会报类似以下错误：

error C2039: 'serialize' : is not a member of 'stdext::map<_Kty,_Ty>'
原因是因为序列化的是map类型，内部是多个键值对，如果序列化非集合类型应该不会出现这种错误 ，
如果你序列化的是其他的集合类型，可以到boost/serialization/下对应的头文件，除此外还要加上链接库
libboost_serialization-xgcc42-d-1_49.a，xcode里是在targets>>build phases>>link binary with libraries
根据平台和版本的不同，xgcc42-d-1_49是会变化的