jsp基于XML实现用户登录与注册的实例解析（附源码）_JSP编程_

 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) { e.printStackTrace();}} //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());}}} } 

 用户名：
 密 码 ：
 验证码：看不清//需要重写一个js进行刷新 
注册

 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");//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 PrintWriter out = response.getWriter(); out.println(""); out.println(""); out.println(" "); out.println(" "); out.println(" "); 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("返回登录"); 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 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("恭喜您，登陆成功！"); out.println("返回登录"); }else{ out.print("用户名和密码不匹配。登录失败。。。"); out.println("返回登录"); } out.println(" "); out.println(""); out.flush(); out.close(); } } 

 用户 名：
 密 码 ： 
 确认密码 ：

 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8");//必须要设置在获得Printwrite之前，都则设置无效 PrintWriter out = response.getWriter(); out.println(""); out.println(""); out.println(" "); out.println(" "); 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 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("返回注册"); }else{ Element ele=root.addElement("user"); ele.addAttribute("name", name); ele.addAttribute("pwd", pwd); DocumentFactory.Save(); out.print("注册成功！！"); out.print("返回登录"); } out.println(" "); out.println(""); }