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Expat+SCEW-操弄XML的瑞士刀作者: Joey 日期: 2008-09-04 18:38 |
之前处理XML文件时,就是用这套工具横行江湖,Expat提供细致的函式读写xml文件,SCEW则是把Expat函式包装成亮丽的界面供使用者更方便的存取xml,个人觉的,这两套函式库实在不输给.net System.xml下的API
首先下载expat library和scew library,这两套软体的使用方式很简单,执行configure,make,make install后,就可以使用它们的library,而我这边的范例编译时用static link,所以我都直接连接它们的.a函式库档
Makefile的范例如下
- ALL:example
- example:example.c
- $(CC)-I./scew-0.4.0/scew/ -oexampleexample.clibscew.alibexpat.a
- clean:
- rmexample
SCEW write xml的方法大概就五组API如下
(1)创造xml tree: tree = scew_tree_create();
(2)加入root element: scew_tree_add_root(scew_tree*,char*);
(3)加入root element的子element: scew_element_add(scew_element*,char*);
(4)加入element attribute: scew_element_add_attr_pair(scew_element*,char*,char*);;
(5)加入element content: scew_element_set_contents(scew_element*,char *);
写入xml文件的范例如下
- intCreateXML()
- {
- scew_tree*tree=NULL;
- scew_element*root=NULL;
- scew_element*element=NULL;
- scew_element*sub_element=NULL;
- scew_element*sub_sub_element=NULL;
- scew_attribute*attribute=NULL;
- tree=scew_tree_create();
- root=scew_tree_add_root(tree,"scew_test");
- /* Add an element and set element contents. */
- element=scew_element_add(root,0)">"element1");
- scew_element_set_contents(element,0)">"element contents.");
- /* Add an element with an attribute pair (name,value). */
- element=scew_element_add(root,0)">"element2");
- scew_element_add_attr_pair(element,0)">"attribute",0)">"value");
- element=scew_element_add(root,0)">"element3"attribute1"value1");
- /**
- * Another way to add an attribute. You loose attribute ownership,
- * so there is no need to free it.
- */
- attribute=scew_attribute_create("attribute2"value2");
- scew_element_add_attr(element,attribute);
- element=scew_element_add(root,0)">"element4");
- sub_element=scew_element_add(element,0)">"sub_element1");
- scew_element_add_attr_pair(sub_element,0)">");
- sub_element=scew_element_add(element,0)">"sub_element2");
- sub_sub_element=scew_element_add(sub_element,0)">"sub_sub_element1");
- scew_element_add_attr_pair(sub_sub_element,0)">"attribute3"value3");
- /* Check attribute2 replacement. */
- scew_element_add_attr_pair(sub_sub_element,0)">"new_value2");
- scew_element_set_contents(sub_sub_element,0)">");
- scew_writer_tree_file(tree,0)">"example.xml");
- scew_tree_free(tree);
- return0;
- }
执行范例会制造出如下内容的xml
- <?xmlversion="1.0"encoding="UTF-8"standalone="no"?>
- <scew_test>
- <element1>elementcontents.</element1>
- <element2attribute="/>
- <element3attribute1="attribute2="/>
- <element4>
- <sub_element1attribute="/>
- <sub_element2attribute1=">
- <sub_sub_element1attribute1="attribute3=">elementcontents.</sub_sub_element1>
- </sub_element2>
- </element4>
- </scew_test>
而SCEW读取xml的方法大约有6组API
(1)创造xml parser: parser = scew_parser_create;
(2)读入xml档案: scew_parser_load_file(scew_parser*,char*)
(3)读出element name: scew_element_name(scew_element*)
(4)读出element attribute: scew_attribute_next(scew_element*,scew_attribute*)
(5)读出element content: scew_element_contents(scew_element*)
(6)寻找子element: scew_element_next(scew_element*,scew_element*)
读取xml文件的范例如下
- voidprint_attributes(scew_element*element)
- {
- scew_attribute*attribute=NULL;
- if(element!=NULL)
- {
- /**
- * Iterates through the element's attribute list,printing the
- * pair name-value.
- */
- attribute=NULL;
- while((attribute=scew_attribute_next(element,attribute))!=NULL)
- printf("%s=\"%s\"",scew_attribute_name(attribute),scew_attribute_value(attribute));
- }
- }
- intPrintElement(scew_element*element)
- {
- scew_element*child=NULL;
- XML_Charconst*contents=NULL;
- printf("element name: %sscew_element_name(element));
- print_attributes(element);
- contents=scew_element_contents(element);
- if(contents==NULL)
- printf("\n\n");
- elseprintf("\n%s content:%s\n\nscew_element_name(element),contents);
- /**
- * Call print_element function again for each child of the
- * current element.
- */
- while((child=scew_element_next(element,child))!=NULL)
- PrintElement(child);
- return0;
- }
- intReadXML()
- {
- scew_tree*tree=NULL;
- scew_parser*parser=NULL;
- scew_element*element=NULL,*parent=NULL;
- /**
- * Creates an SCEW parser. This is the first function to call.
- */
- parser=scew_parser_create();
- scew_parser_ignore_whitespaces(parser,1);
- if(!scew_parser_load_file(parser,0)">"))return0;
- tree=scew_parser_tree(parser);
- PrintElement(scew_tree_root(tree));//traverse all child and siblings of tree
- /* Remember to free tree (scew_parser_free does not free it) */
- scew_tree_free(tree);
- /* Frees the SCEW parser */
- scew_parser_free(parser);
- return0;
完整的范例程式请点此下载
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