xml作为一种最基本的数据保存方式,可以用用。。。虽然有毒
- 下面的代码是如果没有xml存在,就创建一个。如果有就添加user元素
user对象保存一些属性,以便读取
UUID randomUUID = UUID.randomUUID();//uid
user.setUid(randomUUID.toString());
// 想把xml文件写入到WEB-INF/user.xml。。。但是WEB-INF这个文件夹有坑
String contextPath = getServletContext().getContextPath();
String realPath = getServletContext().getRealPath("WEB-INF/user.xml");
File xmlFile = new File(realPath);
if (!xmlFile.exists()) {
Element root = DocumentHelper.createElement("users");
Document document = DocumentHelper.createDocument(root);
//创建文件 ,格式化是的xml文件更有层次
OutputFormat format = OutputFormat.createPrettyPrint();
FileOutputStream file = new FileOutputStream(xmlFile);
XMLWriter xml = new XMLWriter(file,format);
xml.write(document);
xml.close();
}
//解析xml,刚才创建,现在读取,从根节点开始,给添加user元素。
//然后疯狂添加属性,也可以换成添加子元素,
SAXReader reader = new SAXReader();
try {
Document d = (Document) reader.read(xmlFile);
Element root = (Element) d.selectSingleNode("users");
Element userElement = root.addElement("user");
Element aUsername = userElement.addAttribute("username", user.getUsername());
Element aPassword = userElement.addAttribute("password", user.getPassword());
Element aGender = userElement.addAttribute("gender", user.getGender());
Element aAge = userElement.addAttribute("age", user.getAge());
Element aEmail = userElement.addAttribute("email", user.getEmail());
Element aPic = userElement.addAttribute("pic", user.getPic());
Element aUid = userElement.addAttribute("uid", user.getUid());
//这一句可以让xml文件看上去格式正常
OutputFormat format = OutputFormat.createPrettyPrint();
FileOutputStream file = new FileOutputStream(xmlFile);
XMLWriter xml = new XMLWriter(file,format);
xml.write(d);
xml.close();
} catch (DocumentException e) {
e.printStackTrace();
}
ArrayList<User> list = new ArrayList<>();
String contextPath = getServletContext().getContextPath();
String realPath = getServletContext().getRealPath("WEB-INF/user.xml");
File xmlFile = new File(realPath);
SAXReader reader = new SAXReader();
try {
Document d = (Document) reader.read(xmlFile);
Element rootElement = d.getRootElement();
List elements = rootElement.elements();
System.out.println(elements.size());
//System.out.println(selectNodes.size());
for (Object object : elements) {
User user = new User();
System.out.println("haha");
Element ele = (Element) object;
List attributes = ele.attributes();
//拿出账号这个属性
Attribute usernameAttribute = (Attribute) attributes.get(0);
Attribute passwordAttribute = (Attribute) attributes.get(1);
Attribute genderAttribute = (Attribute) attributes.get(2);
Attribute ageAttribute = (Attribute) attributes.get(3);
Attribute emailAttribute = (Attribute) attributes.get(4);
Attribute picAttribute = (Attribute) attributes.get(5);
Attribute uidAttribute = (Attribute) attributes.get(6);
user.setUsername(usernameAttribute.getText());
user.setPassword(passwordAttribute.getText());
user.setGender(genderAttribute.getText());
user.setAge(ageAttribute.getText());
user.setEmail(emailAttribute.getText());
user.setPic(picAttribute.getText());
user.setUid(uidAttribute.getText());
list.add(user);
}
HttpSession session = request.getSession();
session.setAttribute("userList", list);
System.out.println(list);
response.setHeader("Refresh", "0;url='../pages/users.jsp'");
} catch (DocumentException e) {
e.printStackTrace();
}
}
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