5

我正在尝试解析以下 XML 文件：

<root>Root
    <pai>Pai_1
        <filho>Pai1,Filho1</filho>
        <filho>Pai1,Filho2</filho>
    </pai>
    <pai>Pai_2
        <filho>Pai2,Filho1</filho>
        <filho>Pai2,Filho2</filho>
    </pai>
</root>

我正在使用以下 C 代码：

//... open file
xml_tree = mxmlLoadFile(NULL, fp, MXML_TEXT_CALLBACK);

node = xml_tree;
printf("%s\n", mxmlGetText(node, NULL));
// here the return is: Root
// I expected: Root, OK

node = xml_tree->child;
printf("%s\n", mxmlGetText(node, NULL));
// here the return is: Root
// I expected: Pai_1, not OK

node = mxmlGetFirstChild(xml_tree);
printf("%s\n", mxmlGetText(node, NULL));
// here the return is: Root
// I expected: Pai_1, not OK

node = mxmlFindElement(xml_tree, xml_tree, "pai", NULL, NULL, MXML_DESCEND);
printf("%s\n", mxmlGetText(node, NULL));
// here the return is: Pai_1
// I expected: Pai_1, OK

node = mxmlGetNextSibling(node);
printf("%s\n", mxmlGetText(node, NULL));
// here the return is: (NULL)
// I expected: Pai_2, not OK

如何访问根的孩子？我的访问概念在哪里是错误的？

谢谢你。

在@RutgersMike 回复后编辑

我扩展了您的 while 循环以尝试理解 minixml 的概念：

root = mxmlLoadFile(NULL,fp,MXML_TEXT_CALLBACK);
node = root;

printf("------- Root\n");
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

printf("------- First child of Root\n");
node = mxmlGetFirstChild(node);
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

printf("------- Sibling 1 of First child of Root\n");
node = mxmlGetNextSibling(node);
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

printf("------- Sibling 2 of First child of Root\n");
node = mxmlGetNextSibling(node);
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

printf("------- Sibling 3 of First child of Root\n");
node = mxmlGetNextSibling(node);
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

printf("------- Sibling 4 of First child of Root\n");
node = mxmlGetNextSibling(node);
fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
printf("\n");

结果是：

------- Root
Element = root
  Value = Root

------- First child of Root
Element = (null)
  Value = Root

------- Sibling 1 of First child of Root
Element = (null)
  Value = 

------- Sibling 2 of First child of Root
Element = pai
  Value = Pai_1

------- Sibling 3 of First child of Root
Element = (null)
  Value = 

------- Sibling 4 of First child of Root
Element = pai
  Value = Pai_2

我觉得这种在孩子和父母之间导航的概念有点奇怪。为什么兄弟姐妹之间有（空）值？

我正在考虑回到ezxml。

谢谢

4

2 回答 2

7

刚开始玩，min-xml虽然我因缺乏好的例子而感到非常沮丧，但我已经借用和增强了一个不错但不完美的例子来阅读 XML 文件并查看所有部分。它显示标签名称、属性和标签之间的文本值。不确定如何识别结束标签。确保标准 xml 标记位于 xml 文件的顶部。包括stdio, stdlib, string.h 文件。

#include "mxml.h"

int main (int argc, char **argv ) {

         FILE *fp  = NULL;

         int k = 0;

         mxml_node_t * tree = NULL;
         mxml_node_t * node  = NULL;

         if (argc < 2){
             perror("Argument Required XML File ");
             exit(1);
         }
         fp = fopen (argv[1], "r");
         if (fp ){
             tree = mxmlLoadFile (NULL , fp , MXML_OPAQUE_CALLBACK);
         }else {
             perror("Could Not Open the File Provided");
             exit(1);
         }
         if (tree){
                 for (node = mxmlFindElement(tree, tree,NULL,NULL, NULL,MXML_DESCEND);
                         node != NULL;
                         node=mxmlWalkNext (node, NULL, MXML_DESCEND)
                         //node = mxmlFindElement(node, tree, NULL,NULL,NULL,MXML_DESCEND)
                 ){
                         if (node->type  == MXML_ELEMENT) {
                             printf("MXML_ELEMENT Node <%s>:%d \n", node->value.element.name, node->value.element.num_attrs);
                             for (k = 0; k < node->value.element.num_attrs; k++){
                                 if (node->value.element.attrs ){
                                     printf ("Attribute Name :: %s \n", node->value.element.attrs[k].name);
                                     printf ("Attribute Value:: %s \n", node->value.element.attrs[k].value);
                                 }
                                 //if (!strncmp(node->value.element.name , "display-name", 12 )){
                                 //    printf(" String %s \n", (char*) node->child->value.text.string);
                                 //}
                             }
                         }
                         else if (node->type == MXML_REAL){
                             printf("MXML_REAL Node is %s \n", node->value.element.name);
                         }
                         else if(node->type == MXML_OPAQUE){
                             printf("MXML_OPAQUE Node is %s \n", node->value.element.name);
                         }
                         else if(node->type == MXML_INTEGER){
                             printf("MXML_INTEGER Node is %s \n", node->value.element.name);
                         }
                         else if(node->type == MXML_TEXT){
                             printf("MXML_TEXT Node is %s \n", node->value.element.name);
                         }
                         else if(node->type == MXML_IGNORE){
                             printf("MXML_IGNORE Node is %s \n", node->value.element.name);
                         }
                         else if(node->type == MXML_CUSTOM){
                             printf("MXML_IGNORE Node is %s \n", node->value.element.name);
                         }
                         else {
                             printf("Type Default Node is %s \n", node->value.element.name);
                         }
                 }
         }
         if (tree){
            mxmlDelete(tree);
         }
         if (fp){
            fclose(fp);
         }
         return 0;
}
于 2012-07-15T02:55:12.387 回答
6

看起来您想使用此处描述的迭代函数 ( http://www.minixml.org/mxml.html#3_7 ) 来获取子节点。

编辑：我写这个来遍历第一个子节点，它工作正常，使用mxmlGetFirstChild和mxmlGetNextSibling：

<!-- language: c -->
mxml_node_t* node = mxmlLoadFile(NULL,f,MXML_TEXT_CALLBACK);
while ( node != NULL )
{
   switch ( mxmlGetType(node) )
   {
   case MXML_ELEMENT:
   {
      fprintf(stdout,"Element = %s\n",mxmlGetElement(node));
   }
   break;
   case MXML_TEXT:
   {
      fprintf(stdout,"  Value = %s\n",mxmlGetText(node,0));
   }
   break;
   default:
   {
   }
   break;
   }
   mxml_node_t* next = mxmlGetFirstChild(node);
   if ( next != NULL )
   {
      node = next;
   }
   else
   {
      next = mxmlGetNextSibling(node);
      if ( next != NULL )
      {
         node = next;
      }
      else
      {
         node = next;
         fprintf(stdout,"Done\n");
      }
   }
}

产生输出：

Element = root
Value = Root
Value = 
Element = pai
Value = Pai_1
Value = 
Element = filho
Value = Pai1,Filho1

我认为您可以使用其中一个 getParent 函数来迭代备份，或者在深入到子节点之前保存最后一个节点，如果您想遍历整个文件，请使用节点指针堆栈。请注意，我只处理/打印两种节点类型的数据 - 如果您还需要该信息，您将需要尝试查看其他节点类型包含的内容。

** 编辑后进行更多编辑 **

前几天我建议其他人尝试libxml2（http://xmlsoft.org/examples/index.html#xmlReader） - 检查该链接。xmlReader 示例显示了用法。创建读取器并遍历节点非常容易 - 当您点击每个节点时，只需检查它的类型以确保它是您关心的类型（通常是ELEMENT、ATTRIBUTE、TEXT和END_ELEMENT），然后提取名称或值。我比 mxml 更喜欢它。

于 2012-03-21T14:58:28.770 回答