boost操作xml 5分钟官方教程

Five Minute Tutorial

This tutorial uses XML. Note that the library is not specifically bound to XML, and any other supported format (such as INI or JSON) could be used instead. XML was chosen because the author thinks that wide range of people is familiar with it.

Suppose we are writing a logging system for some application, and need to read log configuration from a file when the program starts. The file with the log configuration looks like this:

<debug>
    <filename>debug.log</filename>
    <modules>
        <module>Finance</module>
        <module>Admin</module>
        <module>HR</module>
    </modules>
    <level>2</level>
</debug>

It contains the log filename, a list of modules where logging is enabled, and the debug level value. To store the logging configuration in the program we created a debug_settings structure:

struct debug_settings
{
    std::string m_file;          // log filename
    int m_level;                 // debug level
    std::set<string> m_modules;  // modules where logging is enabled
    void load(const std::string &filename);
    void save(const std::string &filename);
};

All that needs to be done now is to write implementations of load() and save() member functions. Let's first deal with load(). It contains just 7 lines of code, although it does all the necessary things, including error reporting:

ptree
ptree
read_xml
get
get
ptree
value_type
get_child
insert

Now the save() function. It is also 7 lines of code:

ptree
ptree
put
put
add
write_xml

The full program debug_settings.cpp is included in the examples directory.

 

from:http://www.boost.org/doc/libs/1_56_0/doc/html/boost_propertytree/tutorial.html