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 [Java Open Source]动态检查文本框中的数据
软件技术
lhwork 发表于 2006/7/24 10:17:51 |
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ajax技术现在越来越受到大家的欢迎，因为它能很好的解决一些以前不好解决的问题，动态检查文本框中的数据就是体现之一。现在已经加上了数据库mysql，可以说得上是一个比较完整的例子了。下面就是怎样实现动态检查文本框中的数据一个例子：工程目录如下：500)this.width=500'>CheckServlet.java:Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->/** * */package com;import java.io.IOException;import javax.servlet.RequestDispatcher;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * @author Administrator * */public class CheckServlet extends HttpServlet { public String[] usernameList; public CheckServlet() { super(); // TODO Auto-generated constructor stub } private boolean IsContain(String param){ for(int i=0;i<usernameList.length;i++){ if(usernameList[i].equals(param)){ return true; }else{ continue; } } return false; } public void doGet(HttpServletRequest request,HttpServletResponse response)throws IOException,ServletException{ String username=(String)request.getParameter("username"); String password=(String)request.getParameter("password"); String repassword=(String)request.getParameter("repassword"); String email=(String)request.getParameter("email"); if(username.equals("")||username==null){ request.setAttribute("error.message","用户名不能为空!"); RequestDispatcher requsetDispatcher=request.getRequestDispatcher("error.jsp"); requsetDispatcher.forward(request,response); }else if(password.equals("")||password==null){ request.setAttribute("error.message","密码不能为空!"); RequestDispatcher requsetDispatcher=request.getRequestDispatcher("error.jsp"); requsetDispatcher.forward(request,response); }else if(!password.equals(repassword)){ request.setAttribute("error.message","两次输入的密码不一致!"); RequestDispatcher requsetDispatcher=request.getRequestDispatcher("error.jsp"); requsetDispatcher.forward(request,response); }else if(this.IsContain(username)){ request.setAttribute("error.message","您输入的用户名已经存在!"); RequestDispatcher requsetDispatcher=request.getRequestDispatcher("error.jsp"); requsetDispatcher.forward(request,response); }else{ RequestDispatcher requsetDispatcher=request.getRequestDispatcher("success.jsp"); requsetDispatcher.forward(request,response); } } public void doPost(HttpServletRequest request,HttpServletResponse response)throws IOException,ServletException{ doGet(request,response); } public void init(ServletConfig config) throws ServletException{ usernameList=new String[]{"Tom","Jerry","Brain"}; } }PreServlet.java: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->package com;import java.io.IOException;import java.io.PrintWriter;import java.util.Iterator;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class PreServlet extends HttpServlet { public List usernameList; /** * Constructor of the object. */ public PreServlet() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/xml"); response.setHeader("Cache-Control","no-cache"); String username=(String)request.getParameter("user_name"); System.out.println(username); String xml="<?xml version=\"1.0\" encoding=\"UTF-8\"?>"; if(username.equals("")||username==null){ xml+="<message><info>Username is required!</info></message>"; } else if(this.IsContain(username)){ xml+="<message><info>The username has existes,Please choose other username!</info></message>"; } else{ xml+="<message><info>Username is approved!</info></message>"; } response.getWriter().write(xml); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request,response); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occure */ public void init() throws ServletException { // Put your code here DBOperator dBOperator=new DBOperator(); usernameList=dBOperator.getUsernameList(); } private boolean IsContain(String param){ //这里修改了以前的代码，现在是读取数据库的数据。 Iterator it=usernameList.iterator(); while(it.hasNext()){ if(it.next().toString().equals(param)){ return true; }else{ continue; } } return false; }}DBOperator.java: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->package com;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import java.util.ArrayList;import java.util.List;public class DBOperator { public DBOperator(){} public Connection Connect(){ Connection con = null; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); con = java.sql.DriverManager.getConnection("jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=GBK","root",""); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return con; } public List getUsernameList(){ Connection con=Connect(); List usernameList=new ArrayList(); try { Statement stmt=con.createStatement(); ResultSet rst=stmt.executeQuery("select * from m_stuinfo"); while(rst.next()){ usernameList.add(rst.getString("m_stuinfo_name")); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return usernameList; }}index.jsp: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><%@ page language="java" contentType="text/html; charset=utf-8"%><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>注册</title> <SCRIPT type="text/javascript"> var req; function UsrNameCheck() { var username=document.getElementById('username').value; var url="pre?user_name="+username; if(window.XMLHttpRequest) { req=new XMLHttpRequest(); }else if(window.ActiveXObject) { req=new ActiveXObject("Microsoft.XMLHTTP"); } if(req) { req.open("GET",url,true); req.onreadystatechange=callback; req.send(null); } function callback() { if(req.readyState == 4) { if(req.status == 200) { parseMessage(); }else{ alert("Not able to retrieve description"+req.statusText); } }else{ document.getElementById('check_username').innerHTML="正在验证用户名500)this.width=500'>"; } } function parseMessage() { var xmlDoc=req.responseXML.documentElement; alert(xmlDoc); var node=xmlDoc.getElementsByTagName('info'); document.getElementById('check_username').innerHTML=node[0].firstChild.nodeValue; } function Form_Submit() { if(regForm.username.value=="") { alert("用户名不能为空"); return false; }else if(regForm.password.value=="") { alert("密码不能为空"); return false; }else if(regForm.password.value!=regForm.repassword.value) { alert("两次输入的密码不一致"); return false; } regForm.submit(); } } </SCRIPT> </head> <body> <div align="center"> <form name="regForm" method="post" action="/reg/regservlet"> <table width="70%" border="1"> <tr align="center"> <td colspan="2">用户注册</td> </tr> <tr> <td width="24%" align="center">用户名: </td> <td width="76%" ><input name="username" type="text" id="username" onBlur="UsrNameCheck()"> <SPAN id="check_username"></SPAN> </td> </tr> <tr> <td align="center">密码: </td> <td ><input name="password" type="password" id="password"></td> </tr> <tr> <td align="center">重复密码: </td> <td ><input name="repassword" type="password" id="repassword"></td> </tr> <tr> <td align="center">email: </td> <td ><input name="email" type="text" id="email"></td> </tr> <tr align="center"> <td colspan="2"><input type="button" name="Submit" value="提交" onClick="Form_Submit()"></td> </tr> </table> </form> </div> </body></html>success.jsp: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><%@ page language="java" contentType="text/html; charset=GB2312"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB2312"><title>注册成功</title></head><body> 恭喜你，注册成功！<br></body></html>error.jsp: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><%@ page language="java" contentType="text/html; charset=GB2312"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB2312"> <title>失败</title> </head> <body> <div align="center"> <table width="70%" border="1"> <tr> <td>注册失败</td> </tr> <tr> <td> <%=(String)request.getAttribute("error.message") %></td> </tr> <tr> <td><a href="index.jsp">返回注册页</a></td> </tr> </table> </div> </body></html>web.xml: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?xml version="1.0" encoding="UTF-8"?><web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>reg</display-name> <!-- Action Servlet Configuration --> <servlet> <servlet-name>regservlet</servlet-name> <servlet-class>com.CheckServlet</servlet-class> </servlet> <servlet> <servlet-name>PreServlet</servlet-name> <servlet-class>com.PreServlet</servlet-class> </servlet> <!-- Action Servlet Mapping --> <servlet-mapping> <servlet-name>regservlet</servlet-name> <url-pattern>/regservlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>PreServlet</servlet-name> <url-pattern>/pre</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list></web-app>运行结果是:500)this.width=500'> |
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