为了解析xml，可以使用Linux下默认安装的libxml2。
/*
a.c
功能：利用libxml2解析xml文件
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
int GetCurFilePath(char *lpOut) // get full path of the executable file
{
char chPath[BUFSIZ] = {0};
int nRetVal = readlink("/proc/self/exe", chPath, sizeof(chPath)); // get full path of the current-executable file
if(nRetVal < 0)
{
strcpy(lpOut, ".");
return -1;
}
else
{
strcpy(lpOut, chPath);
return 0;
}
}
int GetCurDir(char *lpOut) // get directory-path of current executable-file
{
char chPath[BUFSIZ] = { 0 };
if( GetCurFilePath(chPath) < 0 )
return - 1;
dirname(chPath); // dirname will change value of "chPath"(contain result)
strcpy(lpOut, chPath); // copy result to out-param
return 0;
}
xmlDocPtr getdoc(char *docname) // 根据文件名得到文档指针
{
xmlDocPtr doc;
doc = xmlParseFile(docname);
if(doc == NULL)
{
fprintf(stderr, "Document not parsed successfully.\n");
return NULL;
}
return doc;
}
// 在文档doc中解析xpath表达式，返回结果集指针
xmlXPathObjectPtr getnodeset(xmlDocPtr doc, xmlChar *xpath)
{
xmlXPathContextPtr context;
xmlXPathObjectPtr result;
context = xmlXPathNewContext(doc);
if(context == NULL)
{
printf("Error in xmlXPathNewContent\n");
return NULL;
}
result = xmlXPathEvalExpression(xpath, context); // 在context中解析表达式xpath
xmlXPathFreeContext(context); // 释放context
if(result == NULL)
{
printf("Error in xmlXPathEvalExpression\n");
return NULL;
}
if(xmlXPathNodeSetIsEmpty(result->nodesetval)) // 解析表达式的结果集为空
{
xmlXPathFreeObject(result);
printf("No result\n");
return NULL;
}
return result;
}
// 解析xmlPath路径的结点
void testReadXmlDoc(char *filepath, char *xmlPath)
{
xmlDocPtr doc = getdoc(filepath);
if(NULL == doc)
return ;
xmlChar *xpath = (xmlChar*) xmlPath;
xmlXPathObjectPtr result = getnodeset(doc, xpath); // 获取结果集
if(result)
{
xmlNodeSetPtr nodeset = result->nodesetval;
xmlChar *name, *value;
printf("nodeset->nodeNr = %d\n", nodeset->nodeNr); // 打印结果集中结点个数
for(int i = 0; i < nodeset->nodeNr; i++)
{
xmlNodePtr cur = nodeset->nodeTab[i]; // products
printf("cur->name = %s\n", cur->name);
cur = cur->xmlChildrenNode;
while(cur)
{
if(xmlStrcmp(cur->name, (const xmlChar*) "text")) // cur->name不为"text"
{
printf("cur->name = %s\t", cur->name);
name = xmlGetProp(cur, (const xmlChar*) "name"); // 获取属性值
value = xmlGetProp(cur, (const xmlChar*) "value");
printf("name = %s, value = %s\n", name, value);
xmlFree(name);
xmlFree(value);
}
cur = cur->next;
}
printf("\n");
}
xmlXPathFreeObject(result);
}
xmlFreeDoc(doc);
xmlCleanupParser();
}
int main(void)
{
char curDir[100] = {0};
char docname[100] = {0};
GetCurDir(curDir);
strcpy(docname, curDir);
strcat(docname, "/dprod.xml");
testReadXmlDoc(docname, "/allproducts/products");
return EXIT_SUCCESS;
}
makefile文件：
CC=gcc CFLAGS= BIN=a INC=/usr/include/libxml2 $(BIN): $(BIN).c $(CC) $(CFLAGS) -o $(BIN) $(BIN).c -I$(INC) -lxml2 -std=c99 clean: rm -f *.o $(BIN)
xml文件(dprod.xml)内容：
<?xml version="1.0"?> <allproducts> <products> <product name="name11" value="value11" /> <product name="name12" value="value12" /> <product name="name13" value="value13" /> <product name="name14" value="value14" /> </products> <products> <product name="name21" value="value21" /> <product name="name22" value="value22" /> <product name="name23" value="value23" /> </products> <products> <product name="name31" value="value31" /> <product name="name32" value="value32" /> </products> </allproducts>
编译运行：
[zcm@tmp #115]$make gcc -o a a.c -I/usr/include/libxml2 -lxml2 -std=c99 a.c: 在函数‘GetCurFilePath’中: a.c:18: 警告：隐式声明函数‘readlink’ [zcm@tmp #116]$./a nodeset->nodeNr = 3 cur->name = products cur->name = product name = name11, value = value11 cur->name = product name = name12, value = value12 cur->name = product name = name13, value = value13 cur->name = product name = name14, value = value14 cur->name = products cur->name = product name = name21, value = value21 cur->name = product name = name22, value = value22 cur->name = product name = name23, value = value23 cur->name = products cur->name = product name = name31, value = value31 cur->name = product name = name32, value = value32 [zcm@tmp #117]$
说明：对于编译中出现的“a.c:18: 警告：隐式声明函数‘readlink’”错误，实在不能明白。我查了下手册，这个函数在unistd.h中，而且我也已经#include了，为什么还会出现这个错误呢？
后来突然想到，可能是-std=c99的原因，将它改为-std=gnu99后，这个警告就没有了!
--------------------------------------------------------------------------------------------------------------------------------------------------
修改了xml文件和上面源码中的testReadXmlDoc()后，发现结果相当神奇，看来对libxml2的理解还是比较缺乏。
1. 修改xml文件内容：
<?xml version="1.0"?> <allproducts> <products>h1 <product name="name11" value="value11" />h2 <product name="name12" value="value12" />h3 <product name="name13" value="value13" />h4 <product name="name14" value="value14" />h5 </products> <products> <product name="name21" value="value21" /> <product name="name22" value="value22" /> <product name="name23" value="value23" /> </products> <products> <product name="name31" value="value31" />g1 <product name="name32" value="value32" /> g2</products> </allproducts>
2. 修改testReadXmlDoc()
// 解析xmlPath路径的结点
void testReadXmlDoc(char *filepath, char *xmlPath)
{
xmlDocPtr doc = getdoc(filepath);
if(NULL == doc)
return ;
xmlChar *xpath = (xmlChar*) xmlPath;
xmlXPathObjectPtr result = getnodeset(doc, xpath); // 获取结果集
if(result)
{
xmlNodeSetPtr nodeset = result->nodesetval;
xmlChar *name, *value;
printf("nodeset->nodeNr = %d\n", nodeset->nodeNr); // 打印结果集中结点个数
for(int i = 0; i < nodeset->nodeNr; i++)
{
xmlNodePtr cur = nodeset->nodeTab[i]; // products
printf("cur->name = %s\n", cur->name);
cur = cur->xmlChildrenNode;
int ctext = 0;
while(cur)
{
if(xmlStrcmp(cur->name, (const xmlChar*) "text")) // cur->name不为"text"
{
printf("cur->name = %s\t", cur->name);
name = xmlGetProp(cur, (const xmlChar*) "name"); // 获取属性值
value = xmlGetProp(cur, (const xmlChar*) "value");
printf("name = %s, value = %s\n", name, value);
xmlFree(name);
xmlFree(value);
}
else
{
ctext++;
xmlChar *v = xmlNodeListGetString(doc, cur, 1);
printf("cur->content = [%s], v = [%s]", cur->content, v); // cur->content获取cur的内容
xmlFree(v);
}
cur = cur->next;
}
printf("ctext = %d\n", ctext);
printf("\n");
}
xmlXPathFreeObject(result);
}
xmlFreeDoc(doc);
xmlCleanupParser();
}
运行结果：
[zcm@tmp #168]$make gcc -o a a.c -I/usr/include/libxml2 -lxml2 -std=gnu99 [zcm@tmp #169]$./a nodeset->nodeNr = 3 cur->name = products cur->content = [h1 ], v = [h1 h2 h3 h4 h5 ]cur->name = product name = name11, value = value11 cur->content = [h2 ], v = [h2 h3 h4 h5 ]cur->name = product name = name12, value = value12 cur->content = [h3 ], v = [h3 h4 h5 ]cur->name = product name = name13, value = value13 cur->content = [h4 ], v = [h4 h5 ]cur->name = product name = name14, value = value14 cur->content = [h5 ], v = [h5 ]ctext = 5 cur->name = products cur->content = [ ], v = [ ]cur->name = product name = name21, value = value21 cur->content = [ ], v = [ ]cur->name = product name = name22, value = value22 cur->content = [ ], v = [ ]cur->name = product name = name23, value = value23 cur->content = [ ], v = [ ]ctext = 4 cur->name = products cur->content = [ ], v = [ g1 g2]cur->name = product name = name31, value = value31 cur->content = [g1 ], v = [g1 g2]cur->name = product name = name32, value = value32 cur->content = [ g2], v = [ g2]ctext = 3 [zcm@tmp #170]$
由此可见，一般情况下，我们用的比较多的可能会是cur->content这个东西了!
补充：
在网上看到一个人的写法，可以在解析xml文件时，直接忽略掉结点之间的无效空白。对于本文，就是将：
doc = xmlParseFile(docname); －－－＞修改为：doc = xmlParseFile(docname, "UTF-8",
XML_PARSE_NOBLANKS); // 第3个参数是关键