XML文件——增删改查
1 将数据库表student_table的增删改查用XML来实现：
2 其中，conditionMap存储条件语句，where "xxx" = "xxx"（where conditionMap.begin()->first == conditionMap.begin()->second）
3
4 #include <iostream>
5 #include "tinyxml.h"
6 #include <string>
7 #include <map>
8 using namespace std;
9
10 //判断能否找到指定节点，找不到返回NULL
11 bool FindNode(const string xmlFileName, const map<string, string> &conditionMap, TiXmlElement *&pNode)
12 {
13 //创建XML文档指针
14 TiXmlDocument *pDocument = new TiXmlDocument(xmlFileName.c_str());
15 if (NULL == pDocument)
16 {
17 return false;
18 }
19 pDocument->LoadFile(xmlFileName.c_str());
20
21 TiXmlElement *pRoot = pDocument->RootElement();
22 if (NULL == pRoot)
23 {
24 return false;
25 }
26
27 pNode = pRoot->FirstChildElement();
28 TiXmlElement *pChildNode = NULL;
29 string key = conditionMap.begin()->first;
30 while(pNode != NULL)
31 {
32 pChildNode = pNode->FirstChildElement();
33 while (pChildNode != NULL)
34 {
35 const char *strValue = pChildNode->Value();
36 const char *strText = pChildNode->GetText();
37 if (strcmp(key.c_str(), strValue) == 0)
38 {
39 if (string(strText) == conditionMap.begin()->second)
40 {
41 return true;
42 }
43 else
44 {
45 break;
46 }
47 }
48 pChildNode = pChildNode->NextSiblingElement();
49 }
50 pNode = pNode->NextSiblingElement();
51 }
52 return false;
53 }
54
55 void CreateXMLFile(const string &xmlFileName, const string &version, const string &encoding, const string &standalone)
56 {
57 //创建XML文档指针
58 TiXmlDocument *pDocument = new TiXmlDocument(xmlFileName.c_str());
59 if (NULL == pDocument)
60 {
61 return;
62 }
63
64 //声明XML
65 TiXmlDeclaration *pDeclaration = new TiXmlDeclaration(version.c_str(), encoding.c_str(), standalone.c_str());
66 if (NULL == pDeclaration)
67 {
68 return;
69 }
70 pDocument->LinkEndChild(pDeclaration);
71
72 //创建根节点
73 string rootName = (xmlFileName.substr(0, xmlFileName.find(".")));//根节点元素名为文件名去掉.xml
74 TiXmlElement *pRoot = new TiXmlElement(rootName.c_str());
75 if (NULL == pRoot)
76 {
77 return;
78 }
79 //关联XML文档，成为XML文档的根节点
80 pDocument->LinkEndChild(pRoot);
81 //保存文档
82 pDocument->SaveFile(xmlFileName.c_str());
83 }
84
85 //insert into student_table (id, name, age, score) values ("1", "小明", "18", ""100)
86 void Insert(const string xmlFileName, const map<string, string> &T_Map)
87 {
88 //创建XML文档指针
89 TiXmlDocument *pDocument = new TiXmlDocument(xmlFileName.c_str());
90 if (NULL == pDocument)
91 {
92 return;
93 }
94 pDocument->LoadFile(xmlFileName.c_str());
95
96 TiXmlElement *pRoot = pDocument->RootElement();
97 if (NULL == pRoot)
98 {
99 return;
100 }
101
102 //创建孩子节点
103 string rootName = (xmlFileName.substr(0, xmlFileName.find(".")));//根节点元素名为文件名去掉.xml后+Record
104 rootName += "Record";
105 TiXmlElement *pNode = new TiXmlElement(rootName.c_str());
106 if (NULL == pNode)
107 {
108 return;
109 }
110
111 TiXmlElement *pColumnNode = NULL;
112 TiXmlText *pColumnText = NULL;
113 for (auto it = T_Map.begin(); it != T_Map.end(); ++it)
114 {
115 pColumnNode = new TiXmlElement(it->first.c_str());
116 pColumnText = new TiXmlText(it->second.c_str());
117 pColumnNode->LinkEndChild(pColumnText);
118 pNode->LinkEndChild(pColumnNode);
119 }
120
121 pRoot->InsertEndChild(*pNode);
122 pDocument->SaveFile(xmlFileName.c_str());
123 }
124
125 //delete from student_table where "xxx" = "xxx"
126 void Delete(const string xmlFileName, const map<string, string> &conditionMap)
127 {
128 //创建XML文档指针
129 TiXmlDocument *pDocument = new TiXmlDocument(xmlFileName.c_str());
130 if (NULL == pDocument)
131 {
132 return;
133 }
134 pDocument->LoadFile(xmlFileName.c_str());
135
136 TiXmlElement *pRoot = pDocument->RootElement();
137 if (NULL == pRoot)
138 {
139 return;
140 }
141
142 TiXmlElement *pNode = pRoot->FirstChildElement();
143 TiXmlElement *pChildNode = NULL;
144 string key = conditionMap.begin()->first;
145 while(pNode != NULL)
146 {
147 pChildNode = pNode->FirstChildElement();
148 while (pChildNode != NULL)
149 {
150 const char *strValue = pChildNode->Value();
151 const char *strText = pChildNode->GetText();
152 if (strcmp(key.c_str(), strValue) == 0)
153 {
154 if (string(strText) == conditionMap.begin()->second)
155 {
156 pRoot->RemoveChild(pNode);
157 pDocument->SaveFile(xmlFileName.c_str());
158 return;
159 }
160 else
161 {
162 break;
163 }
164
165 //pChildNode->Clear();
166 //TiXmlText *pText = new TiXmlText(T_Map.begin()->second.c_str());
167 //pChildNode->LinkEndChild(pText);
168 //pDocument->SaveFile(xmlFileName.c_str());
169 }
170 pChildNode = pChildNode->NextSiblingElement();
171 }
172 pNode = pNode->NextSiblingElement();
173 }
174 }
175
176 //update student_table set column1 = value1, column2 = value2, ... where "xxx" = "xxx";
177 void UpDate(const string xmlFileName, const map<string, string> &Set_Map, const map<string, string> &Condition_Map)
178 {
179 //创建XML文档指针
180 TiXmlDocument *pDocument = new TiXmlDocument(xmlFileName.c_str());
181 if (NULL == pDocument)
182 {
183 return;
184 }
185 pDocument->LoadFile(xmlFileName.c_str());
186
187 TiXmlElement *pRoot = pDocument->RootElement();
188 if (NULL == pRoot)
189 {
190 return;
191 }
192
193 TiXmlElement *pNode = pRoot->FirstChildElement();
194 TiXmlElement *pChildNode = NULL;
195 string key = Condition_Map.begin()->first;
196 while(pNode != NULL)
197 {
198 pChildNode = pNode->FirstChildElement();
199 while (pChildNode != NULL)
200 {
201 const char *strValue = pChildNode->Value();
202 const char *strText = pChildNode->GetText();
203 if (strcmp(key.c_str(), strValue) == 0)
204 {
205 if (string(strText) == Condition_Map.begin()->second)
206 {
207 //用oldMap存储更新前的记录信息，
208 map<string, string> oldMap;
209 TiXmlElement *pFirstChildNode = pNode->FirstChildElement();
210 for (; pFirstChildNode; pFirstChildNode = pFirstChildNode->NextSiblingElement())
211 {
212 string strValue = pFirstChildNode->Value();
213 string strText = pFirstChildNode->GetText();
214 oldMap[strValue] = strText;
215 }
216 //oldMap保存更新后记录信息
217 for (auto it = Set_Map.begin(); it != Set_Map.end(); ++it)
218 {
219 oldMap[it->first] = it->second;
220 }
221 //清空XML中的孩子结点（清空所有字段信息）
222 pNode->Clear();
223
224 TiXmlElement *pColumnNode = NULL;
225 TiXmlText *pColumnText = NULL;
226 for (auto it = oldMap.begin(); it != oldMap.end(); ++it)
227 {
228 pColumnNode = new TiXmlElement(it->first.c_str());
229 pColumnText = new TiXmlText(it->second.c_str());
230 pColumnNode->LinkEndChild(pColumnText);
231 pNode->LinkEndChild(pColumnNode);
232 }
233
234 pDocument->SaveFile(xmlFileName.c_str());
235 return;
236 }
237 else
238 {
239 break;
240 }
241 }
242 pChildNode = pChildNode->NextSiblingElement();
243 }
244 pNode = pNode->NextSiblingElement();
245 }
246 }
247
248 //select * from student_table where "xxx" = "xxx";
249 map<string, string> SelectAll(const string xmlFileName, const map<string, string> &conditionMap)
250 {
251 map<string, string> resMap;
252 TiXmlElement *pNode;
253 if (FindNode(xmlFileName, conditionMap, pNode))
254 {
255 TiXmlElement *pChildNode = pNode->FirstChildElement();
256 while (pChildNode != NULL)
257 {
258 string strValue = pChildNode->Value();
259 string strText = pChildNode->GetText();
260 resMap[strValue] = strText;
261 pChildNode = pChildNode->NextSiblingElement();
262 }
263 }
264
265 return resMap;
266 }
267
268 int main()
269 {
270 string xmlFileName = "Student.xml";
271 string version = "1.0";
272 string encoding = "UTF-8";
273 string standalone = "";
274
275 map<string, string> _Map;
276 _Map["a_id"] = "1";
277 _Map["b_name"] = string("张");
278 _Map["c_age"] = "18";
279 _Map["d_score"] = "100";
280 map<string, string> conditionMap;
281 //创建文件：create student_table
282 CreateXMLFile(xmlFileName, version, encoding, standalone);
283 //插入记录：insert into student_table
284 Insert(xmlFileName, _Map);
285 _Map["a_id"] = "2";
286 Insert(xmlFileName, _Map);
287 _Map["a_id"] = "3";
288 Insert(xmlFileName, _Map);
289
290 //删除记录：delete from student_table where "xxx" = "xxx";
291 conditionMap["a_id"] = "2";
292 Delete(xmlFileName, conditionMap);
293
294 //更新记录：
295 _Map["a_id"] = "4";
296 _Map["c_age"] = "25";
297 conditionMap["a_id"] = "3";
298 UpDate(xmlFileName, _Map, conditionMap);
299
300 //查询记录：
301 map<string, string> resMap;
302 conditionMap["a_id"] = "4";
303 resMap = SelectAll(xmlFileName, conditionMap);
304 for (auto it = resMap.begin(); it != resMap.end(); ++it)
305 {
306 cout << it->first << " : " << it->second << endl;
307 }
308 system("pause");
309 }
标签：XML,string,改查,pChildNode,xmlFileName,pNode,str,增删,NULL From： https://www.cnblogs.com/Jack-Elvis/p/18530188