libxml2用xpath进行查找

xml文档

xml version="1.0" encoding="UTF-8"?>
<radios>
    <radio>
        <name>Bayernname>
        <url>url>
        <classification>
            <area>usaarea>
            <style>musicstyle>
        classification>
    radio>
    <radio>
        <name>DEU-Antenne Bayernname>
        <url>url>
    radio>
    <radio>
        <name>DEU-Antenne Bayernname>
        <url>url>
    radio>
radios>

上代码

static xmlXPathObjectPtr getNodeset(xmlDocPtr doc, const xmlChar *xpath)
{
    xmlXPathContextPtr context;
    xmlXPathObjectPtr result;
    context = xmlXPathNewContext(doc);

    if (context == NULL) {
        printf("context is NULL\n");
        return NULL;
    }

    result = xmlXPathEvalExpression(xpath, context);
    xmlXPathFreeContext(context);
    if (result == NULL) {
        printf("xmlXPathEvalExpression return NULL\n");
        return NULL;
    }

    if (xmlXPathNodeSetIsEmpty(result->nodesetval)) {
        xmlXPathFreeObject(result);
        printf("nodeset is empty\n");
        return NULL;
    }

    return result;
}

playlistDoc 为 xmlDocPtr类型.

xmlChar *xpath = BAD_CAST("/radios/radio[name='DEU-Antenne Bayern']");   //关键在这行
xmlXPathObjectPtr app_result = getNodeset(playlistDoc, xpath);
if (app_result == NULL)
{
    printf("app_result is NULL\n");
    return;
}

int i = 0;
xmlChar *value;
if(app_result)
{
    xmlNodeSetPtr nodeset = app_result->nodesetval;
    xmlNodePtr cur;

    for (i=0; i < nodeset->nodeNr; i++)
    {
        cur = nodeset->nodeTab[i];
        cur = cur->xmlChildrenNode;

        while (cur != NULL)
        {
            if (!xmlStrcmp(cur->name, (const xmlChar *)"name"))
                printf("%s\n", ((char*)XML_GET_CONTENT(cur->xmlChildrenNode)));
            else if (!xmlStrcmp(cur->name, (const xmlChar *)"url"))
                printf("%s\n", ((char*)XML_GET_CONTENT(cur->xmlChildrenNode)));

            cur = cur->next;
        }
    }

    xmlXPathFreeObject(app_result);
}

输出:

DEU-Antenne Bayern

DEU-Antenne Bayern

xmlChar *xpath = BAD_CAST("/radios/radio[name='DEU-Antenne Bayern']");

改成

xmlChar *xpath = BAD_CAST("/radios/radio[name='DEU-Antenne Bayern' and url='']");
EU-Antenne Bayern

输出:

更多xpath的写法可参考

作者:帅得不敢出门   c++哈哈堂:31843264