boost::property_tree XML 漂亮打印 [英] boost::property_tree XML pretty printing

问题描述

我正在使用 boost::property_tree 在我的应用程序中读取和写入 XML 配置文件.但是当我编写文件时，输出看起来有点难看，文件中有很多空行.问题是它也应该由人类编辑，所以我想获得更好的输出.

I'm using boost::property_tree to read and write XML configuration files in my application. But when I write the file the output looks kind of ugly with lots of empty lines in the file. The problem is that it's supposed to be edited by humans too so I'd like to get a better output.

举个例子，我写了一个小测试程序:

As an example I wrote a small test program :

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/xml_parser.hpp>

int main( void )
{
    using boost::property_tree::ptree;
    ptree pt;

    // reading file.xml
    read_xml("file.xml", pt);

    // writing the unchanged ptree in file2.xml
    boost::property_tree::xml_writer_settings<char> settings('	', 1);
    write_xml("file2.xml", pt, std::locale(), settings);

    return 0;
}

file.xml 包含:

file.xml contains:

<?xml version="1.0" ?>
<config>
    <net>
        <listenPort>10420</listenPort>
    </net>
</config>

运行后的程序file2.xml包含:

after running the program file2.xml contains:

<?xml version="1.0" encoding="utf-8"?>
<config>



    <net>



        <listenPort>10420</listenPort>
    </net>
</config>

除了手动查看输出并删除空行之外，还有什么方法可以获得更好的输出?

Is there a way to have a better output, other than going manually through the output and deleting empty lines?

推荐答案

解决方案是在对 read_xml 的调用中添加 trim_whitespace 标志:

The solution was to add the trim_whitespace flag to the call to read_xml:

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/xml_parser.hpp>

int main( void )
{
    // Create an empty property tree object
    using boost::property_tree::ptree;
    ptree pt;

    // reading file.xml
    read_xml("file.xml", pt, boost::property_tree::xml_parser::trim_whitespace );

    // writing the unchanged ptree in file2.xml
    boost::property_tree::xml_writer_settings<char> settings('	', 1);
    write_xml("file2.xml", pt, std::locale(), settings);

    return 0;
}

该标志记录在此处 但该库的当前维护者 (Sebastien Redl) 很友好地回答并指出了它.

The flag is documented here but the current maintainer of the library (Sebastien Redl) was kind enough to answer and point me to it.

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