基于XML的数据存储读取---实现的登录与注册

来源：互联网发布：上知传媒编辑：程序博客网时间：2024/06/05 02:44

简单的基于xml做数据库的登录与注册

主题介绍：

1.xml的读取和存储，主要是用到dom4j技术，（网络中的文件存储路径采用classLoader）

文件的读取和存储，写了一个工厂类

public class DocumentFactory {private static Document dom=null;//需要共享一个dom，所以需要设置为static private static String name="user.xml";private static String filename;

//写一个静态块实现对dom树的读取

static{//dom4j技术SAXReader read=new SAXReader(); filename=DocumentFactory.class.getClassLoader().getResource(name).getPath();//采用类加载器进行读取文件 try {dom=read.read(filename);} catch (DocumentException e) {<span style="font-family: Arial, Helvetica, sans-serif;">e.printStackTrace();}}</span>

//主要获得和存储的两个函数（采用单例模式）（必须共享一个dom数）

public static  Document getDocument(){ //获得xml中的dom树return dom;}

//注册之后需要保存

public static void Save() {XMLWriter wr;try {wr = new XMLWriter(new FileOutputStream(filename));}catch (Exception e1) {throw new RuntimeException("存储文件时读文件失败");}try {wr.write(dom);} catch (IOException e) {throw new RuntimeException("写文件失败"+e.getMessage());}finally{try {if(wr!=null){wr.close();}} catch (IOException e) {throw new RuntimeException("关流失败"+e.getMessage());}}}}

2.前台的技术：基本上就是界面的搭建和将数据传到后台进行处理。以及部分的必填选项要求

两个页面的代码：

//登录

<body>   <form action='login' method="post">   用户名：<input type="text" name="name" /><br/>   密 码 ：<input type="text" name="pwd" /><br/>   验证码：<input type="text" name="checkCode"><img src="/LOGIN/immg" id='imgid'><a href="javascript:flush()">看不清</a>//需要重写一个js进行刷新   <br/>   <input type="submit"value="登录" />    <input type="reset"value="重置" />   <a href='jsps/Reg.jsp'>注册</a>      </form>

//登录后台的处理

public class Login extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");//设置utf-8的编码格式去接收response.setContentType("text/html;charset=UTF-8");//<span style="color:#ff0000;">设置页面显示方式，这个设置必须要在获得输出流之前设置，不然设置都没有用，照样会出现乱码</span>PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println("  <HEAD><TITLE>A Servlet</TITLE>");out.println(" <meta http-equiv='content-type' content='text/html; charset=UTF-8'> </HEAD>");out.println("  <BODY>");String name=request.getParameter("name");String pwd=request.getParameter("pwd");String check=request.getParameter("checkCode");//从界面获得验证码输入的值ImgDemo id =new ImgDemo();String str=id.getStr();if(!check.equals(str)){out.println("登录失败，验证码不正确！！");//要是验证码不符合，直接返回登录界面out.print("<a href='index.jsp'>返回登录</a>");return;}//System.out.println("11"+check);//System.out.println("22"+str);//登录前获得所有的对象Document dom=DocumentFactory.getDocument();boolean flag=false;Element root=dom.getRootElement();Iterator<Element> it=root.elementIterator();while(it.hasNext()){Element ele =it.next();String nameC=ele.attributeValue("name");String pwdC=ele.attributeValue("pwd");if(name.trim().equals(nameC)&&pwdC.equals(pwdC)){flag=true;break;}}if(flag){out.print("<font color='red' size='8px'>恭喜您，登陆成功！</font>");out.println("<a href='index.jsp'>返回登录</a>");}else{out.print("用户名和密码不匹配。登录失败。。。");out.println("<a href='index.jsp'>返回登录</a>");}out.println("  </BODY>");out.println("</HTML>");out.flush();out.close();}}

//注册。。（和登录没有太大的区别）

 <body>   <form action='reg' method="post">   用户 名：<input type="text" name="name" onblur="check()" id="name"/><span id="spanid"></span><br/>   密    码  ： <input type="text" name="pwd" id="pwd" onblur="check1()"/><span id="spanid1"></span><br/>   确认密码 ：<input type="text" name="pwd2" id="pwd2" onblur="check2()"/><span id="spanid2"></span><br/>   <input type="submit"value="注册" />    <input type="reset"value="重置" />      </form>  </body>

注册的后台处理

public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=utf-8");//<span style="color:#ff0000;">必须要设置在获得Printwrite之前，都则设置无效</span>PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");out.println("  <BODY>");boolean flag=false;request.setCharacterEncoding("utf-8");String name=request.getParameter("name");String pwd=request.getParameter("pwd");Document dom =DocumentFactory.getDocument();Element root=dom.getRootElement();Iterator<Element> it=root.elementIterator();while(it.hasNext()){Element ele=it.next();String nameR=ele.attributeValue("name");//这里传过来的值可能是null.所以我们必须在前台要预防一下，当然在这里也要考虑一下String pwdR=ele.attributeValue("pwd");if(name.equals(nameR)&&pwd.equals(pwdR)){flag=true;break;}}if(flag){out.print("此用户已注册！！");out.print("<a href='jsps/Reg.jsp'>返回注册</a>");}else{Element ele=root.addElement("user");ele.addAttribute("name", name);ele.addAttribute("pwd", pwd);DocumentFactory.Save();out.print("注册成功！！");out.print("<a href='index.jsp'>返回登录</a>");}out.println("  </BODY>");out.println("</HTML>");}