我在这里粘贴一些代码,在没有警告的情况下使用gcc file.c -lxml2编译,假定libxml2安装在您的系统中。命名空间和xpath的libxml2错误
#include <libxml/parser.h>
#include <libxml/xpath.h>
#include <assert.h>
#include <libxml/tree.h>
#include <libxml/xpathInternals.h>
xmlDocPtr
getdoc (char *docname) {
xmlDocPtr doc;
doc = xmlParseFile(docname);
if (doc == NULL) {
fprintf(stderr,"Document not parsed successfully. \n");
return NULL;
}
return doc;
}
xmlXPathObjectPtr
getnodeset (xmlDocPtr doc, xmlChar *xpath){
xmlXPathContextPtr context;
xmlXPathObjectPtr result;
context = xmlXPathNewContext(doc);
if (context == NULL) {
printf("Error in xmlXPathNewContext\n");
return NULL;
}
if(xmlXPathRegisterNs(context, BAD_CAST "new", BAD_CAST "http://www.example.com/new") != 0) {
fprintf(stderr,"Error: unable to register NS with prefix");
return NULL;
}
result = xmlXPathEvalExpression(xpath, context);
xmlXPathFreeContext(context);
if (result == NULL) {
printf("Error in xmlXPathEvalExpression\n");
return NULL;
}
if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
xmlXPathFreeObject(result);
printf("No result\n");
return NULL;
}
return result;
}
int
main(int argc, char **argv) {
char *docname;
xmlDocPtr doc;
xmlChar *xpath = (xmlChar*) "/new:book/section1";
xmlNodeSetPtr nodeset;
xmlXPathObjectPtr result;
int i;
xmlChar *keyword;
if (argc <= 1) {
printf("Usage: %s docname\n", argv[0]);
return(0);
}
docname = argv[1];
doc = getdoc(docname);
result = getnodeset (doc, xpath);
if (result) {
nodeset = result->nodesetval;
for (i=0; i < nodeset->nodeNr; i++) {
keyword = xmlNodeListGetString(doc, nodeset->nodeTab[i]->xmlChildrenNode, 1);
printf("keyword: %s\n", keyword);
xmlFree(keyword);
}
xmlXPathFreeObject (result);
}
xmlFreeDoc(doc);
xmlCleanupParser();
return (1);
}
我的问题是,我想分析下面的XML
<?xml version="1.0" encoding="UTF-8"?>
<book xmlns="http://www.example.com/new">
<section1>Sec_1</section1>
<section2>Sec_2</section2>
</book>
书元素定义元素内的命名空间。我想打印xpath/book/section1中的值,并返回NULL。当我试图返回名称空间下的元素时,我也会收到错误,例如/ new:book/section1
我假设我的代码失败,因为我没有正确使用名称空间前缀。我没有时间。能否请你帮忙?
是否可以告诉'libxml',有些命名空间是默认/隐含的文档中的所有元素,以避免过度重复它,在XPath查询结束? – SasQ 2013-08-21 19:12:29