OS環境：
Centos 7.1 release
X86_64
編譯環境:
G++ 4.8.3
已經成功搭建好了Mongodb，也初步在命令行中的查詢與寫入數據的基本方法，現在通過C++來連接Mongodb。
1.准備工作
(1).在官網中下載mongodb的C++ driver
官方文檔說明：
https://github.com/mongodb/mongo-cxx-driver/wiki/Download-and-Compile-the-Legacy-Driver
值得注意的是，上方文檔說明中的git倉庫已經不可用，在github中可以搜索到，使用如下地址
https://github.com/mongodb/mongo-cxx-driver.git
clone下來：
git clone https://github.com/mongodb/mongo-cxx-driver.git
(2).安裝構建工具
mongodb 使用scons工具來自動化構建mongodb driver for c++， 而我centos上沒有預裝這個工具，為了節省時間，我直接使用yum來安裝
yum install scons。
(3).安裝Mongodb驅動 / mongodb-c++開發中所必需的庫。這就是復雜但是好用，龐大但是很富有精華的強大的Boost庫。
為了節省時間，我也選用的是二進制包來安裝，需要的話也可以選擇源碼編譯。
yum install boost-devel
安裝完成之后，當前在我的Centos上，頭文件存在於/usr/include/boost ， 動態庫文件存在與/usr/lib64/ 下.
安裝Boost庫也是編譯C++ mongodb驅動的必要步驟.
2.開始編譯driver
(1).編譯mongodb-cxx-driver
在上述准備工作都已做好的時候，就可以來編譯驅動了。
cd mongo-cxx-driver ， 直接 scons 命令，就開始自動編譯構建驅動 [ 需要更改安裝路徑的可以選擇 --prefix=$HOME/local/mongo ]選項，在編譯的時候若系統中沒有存在Boost開發庫的話，會報錯，提示需要安裝boost開發庫，若需要請先看第三步。確認無誤之后，編譯完成會構建出build目錄，目錄結構：
|-build
|-----install
|----------include
|----------lib
|-----linux2
|-----scons
在這里，我們需要的是install/include 與 install/lib文件。而且lib下只有一個庫文件libmongodbclient.a
cd build
cp include ~/local/include
cp lib ~/local/lib
復制到我們常用開發的頭文件與庫文件目錄中。
我在編譯的時候沒有遇到過報錯。這樣，驅動已成功編譯完成
3.使用C++來連接Mongodb
/** * Mongodb connect for c++ * author kk * 2015/06/17 */ #include <iostream> #include "mongo/client/dbclient.h" using namespace mongo; using namespace std; void run(){ DBClientConnection c; c.connect("localhost"); } int main(){ try{ run(); cout<<"connect ok"<<endl; }catch(DBException &e){ cout<<"caught"<<e.what()<<endl; } return 0; }
單個文件就不使用makefile了，輸入命令
g++ main.cpp -I ~/local/include/ ~/local/lib/libmongoclient.a -lboost_thread-mt -lboost_filesystem -lboost_program_options
在大多數教程中會提醒你這么來編譯你的源代碼，但是，這樣會報錯，詳見錯誤
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign(char const*, char const*, unsigned int)':
/usr/include/boost/regex/v4/basic_regex.hpp:382: undefined reference to `boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign(char const*, char const*, unsigned int)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::unwind_extra_block(bool)':
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:1117: undefined reference to `boost::re_detail::put_mem_block(void*)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::cpp_regex_traits_implementation<char>::error_string(boost::regex_constants::error_type) const':
/usr/include/boost/regex/v4/cpp_regex_traits.hpp:447: undefined reference to `boost::re_detail::get_default_error_string(boost::regex_constants::error_type)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `void boost::re_detail::raise_error<boost::regex_traits_wrapper<boost::regex_traits<char, boost::cpp_regex_traits<char> > > >(boost::regex_traits_wrapper<boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::error_type)':
/usr/include/boost/regex/pattern_except.hpp:75: undefined reference to `boost::re_detail::raise_runtime_error(std::runtime_error const&)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::cpp_regex_traits_implementation<char>::error_string(boost::regex_constants::error_type) const':
/usr/include/boost/regex/v4/cpp_regex_traits.hpp:445: undefined reference to `boost::re_detail::get_default_error_string(boost::regex_constants::error_type)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::cpp_regex_traits<char>::transform_primary(char const*, char const*) const':
/usr/include/boost/regex/v4/cpp_regex_traits.hpp:923: undefined reference to `boost::re_detail::cpp_regex_traits_implementation<char>::transform_primary(char const*, char const*) const'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::cpp_regex_traits<char>::transform(char const*, char const*) const':
/usr/include/boost/regex/v4/cpp_regex_traits.hpp:919: undefined reference to `boost::re_detail::cpp_regex_traits_implementation<char>::transform(char const*, char const*) const'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::extend_stack()':
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:213: undefined reference to `boost::re_detail::get_mem_block()'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `save_state_init':
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:107: undefined reference to `boost::re_detail::get_mem_block()'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::match_imp()':
/usr/include/boost/regex/v4/perl_matcher_common.hpp:206: undefined reference to `boost::re_detail::verify_options(unsigned int, boost::regex_constants::_match_flags)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `~save_state_init':
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:115: undefined reference to `boost::re_detail::put_mem_block(void*)'
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:115: undefined reference to `boost::re_detail::put_mem_block(void*)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `perl_matcher':
/usr/include/boost/regex/v4/perl_matcher.hpp:374: undefined reference to `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::construct_init(boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags)'
/home/kangkai/local/lib/libmongoclient.a(dbclient.o): In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::match_match()':
/usr/include/boost/regex/v4/perl_matcher_non_recursive.hpp:973: undefined reference to `boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > > >::maybe_assign(boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > > > const&)'
collect2: error: ld returned 1 exit status
對於向來喜歡編譯來安裝的我來說，這樣的錯誤實在郁悶了一陣。導致這樣的原因無非就是動態庫鏈接錯誤，找不到聲明與符號。根據提示，只需在編譯時加上動態庫就好了。
g++ main.cpp -I ~/local/include/ ~/local/lib/libmongoclient.a /usr/lib64/libboost_regex-mt.so -lboost_thread-mt -lboost_filesystem -lboost_program_options
OK，無輸出即便就是正確。
./a.out
connect ok
4.結尾
到這里，C++連接Mongodb已經成功，只是需要Boost庫略顯龐大。