[英]Get values from XML <tag> in C++ using libxml2
我很難從XML文件中獲取值。 我們使用libxml2和python(輸出到* .txt),然后使用C ++讀取* .txt文件。
我想在C ++中使用libxml2,而無需通過Python。 我的問題是讀者(請參見下面的示例)。 順便說一句:我從http://xmlsoft.org/examples/index.html#reader1.c的示例代碼中得到的並不多
有人可以告訴我如何獲取value = xmlTextReaderConstValue(reader);
成串?
總結:遍歷XMLdoc {如果“ XML-tag-” =='tag'然后在mystring中存儲“ XML-tag-”的值/內容}
中號
/**
* section: xmlReader
* synopsis: Parse an XML file with an xmlReader
* purpose: Demonstrate the use of xmlReaderForFile() to parse an XML file
* and dump the informations about the nodes found in the process.
* (Note that the XMLReader functions require libxml2 version later
* than 2.6.)
* usage: reader1 <filename>
* test: reader1 test2.xml > reader1.tmp && diff reader1.tmp $(srcdir)/reader1.res
* author: Daniel Veillard
* copy: see Copyright for the status of this software.
*/
#include <stdio.h>
#include <libxml/xmlreader.h>
#ifdef LIBXML_READER_ENABLED
/**
* processNode:
* @reader: the xmlReader
*
* Dump information about the current node
*/
static void
processNode(xmlTextReaderPtr reader) {
const xmlChar *name, *value;
name = xmlTextReaderConstName(reader);
if (name == NULL)
name = BAD_CAST "--";
value = xmlTextReaderConstValue(reader);
printf("%d %d %s %d %d",
xmlTextReaderDepth(reader),
xmlTextReaderNodeType(reader),
name,
xmlTextReaderIsEmptyElement(reader),
xmlTextReaderHasValue(reader));
if (value == NULL)
printf("\n");
else {
if (xmlStrlen(value) > 40)
printf(" %.40s...\n", value);
else
printf(" %s\n", value);
}
}
/**
* streamFile:
* @filename: the file name to parse
*
* Parse and print information about an XML file.
*/
static void
streamFile(const char *filename) {
xmlTextReaderPtr reader;
int ret;
reader = xmlReaderForFile(filename, NULL, 0);
if (reader != NULL) {
ret = xmlTextReaderRead(reader);
while (ret == 1) {
processNode(reader);
ret = xmlTextReaderRead(reader);
}
xmlFreeTextReader(reader);
if (ret != 0) {
fprintf(stderr, "%s : failed to parse\n", filename);
}
} else {
fprintf(stderr, "Unable to open %s\n", filename);
}
}
int main(int argc, char **argv) {
if (argc != 2)
return(1);
/*
* this initialize the library and check potential ABI mismatches
* between the version it was compiled for and the actual shared
* library used.
*/
LIBXML_TEST_VERSION
streamFile(argv[1]);
/*
* Cleanup function for the XML library.
*/
xmlCleanupParser();
/*
* this is to debug memory for regression tests
*/
xmlMemoryDump();
return(0);
}
#else
int main(void) {
fprintf(stderr, "XInclude support not compiled in\n");
exit(1);
}
#endif
我一直在使用此強制轉換來從const xmlChar *中獲取std :: string:
my_std_string.assign(reinterpret_cast<const char*>(my_const_xmlchar_ptr));
我認為您所說的“ XML-tag-”實際上是xmlTextReaderConstName(reader)
的返回值, name
,它是一個const xmlChar *。 (請參閱libxml2 xmlreader)
如果字符串匹配,則可以使用xmlTextReaderConstValue(reader);
再次獲取value
const xmlChar * xmlTextReaderConstValue(reader);
函數,以相同的方式轉換為字符串,然后將其存儲。
value
已經是一個以C空終止(並且靜態分配)的字符串。
如果要獲取std::string
,可以使用類似以下內容的代碼:
std::string val = value;
如果要由您擁有的以C終止的C字符串:
xmlChar* val = xmlStrdup(value);
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