基于DWR框架的验证用户名是否存在的Ajax应用
http://hi.baidu.com/homefovever/blog/item/49d1f900c49e4782e850cd38.html
PersonDAO.java
package com.jj.dao;import java.sql.*;import com.jj.util.DBConnection;public class PersonDAO {public boolean isExist(String username) { Connection conn = DBConnection.getConnection(); try { String query = "SELECT * FROM people WHERE name='" + username + "'"; Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery(query); rs.next(); if (rs.getRow() == 0) { return false; } else { return true; } } catch (SQLException e) { e.printStackTrace(); return true; }}}
package com.jj.dwr;import com.jj.dao.*;public class PersonDAOAjax {public boolean isExist(String username) { PersonDAO personDAO = new PersonDAO(); return personDAO.isExist(username);}}
package com.jj.pojo;public class Person {private String username;private String password;public String getUsername() { return username;}public void setUsername(String username) { this.username = username;}public String getPassword() { return password;}public void setPassword(String password) { this.password = password;}}
package com.jj.util;import java.sql.Connection;import java.sql.DriverManager;public class DBConnection {public static Connection getConnection() { String uri = "jdbc:mysql://localhost/Test"; String name = "root"; String pwd = ""; Connection conn = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(uri, name, pwd); return conn; } catch (Exception e) { e.printStackTrace(); return null; }}}
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"pageEncoding="ISO-8859-1"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head> <title>Register</title></head><body> <script type="text/javascript" src="dwr/engine.js"></script> <script type="text/javascript" src="dwr/util.js"></script> <script type="text/javascript" src="dwr/interface/PersonDAOAjax.js"></script> <script type="text/javascript"> function show(boolean){ var name = document.getElementById("name"); if(boolean){ ${"error"}.style.visibility = "visible"; name.style.borderStyle = "solid"; name.style.borderColor = "red"; dwr.util.setValue("name",""); } else { ${"error"}.style.visibility = "hidden"; name.style.borderStyle = ""; name.style.borderColor = ""; } } function validate(){ var name = dwr.util.getValue("name"); PersonDAOAjax.isExist(name,show); } </script> <h1> Register </h1> <p> username <input type="text" id="name" onchange="validate()" /> <span id="error" style="visibility: hidden">This username has been used by others</span> <br> password <input type="password" id="password" /> </p></body></html>
?xml version="1.0" encoding="UTF-8"?><!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.org/dwr/dwr20.dtd"><dwr><allow> <create javascript="PersonDAOAjax" creator="new"> <param name="class" value="com.jj.dwr.PersonDAOAjax"></param> </create> <convert match="com.jj.pojo.Person" converter="bean"></convert></allow></dwr> ------------
<servlet> <servlet-name>dwr-invoker</servlet-name> <servlet-class> org.directwebremoting.servlet.DwrServlet </servlet-class> <init-param> <param-name>debug</param-name> <param-value>true</param-value> </init-param></servlet><servlet-mapping> <servlet-name>dwr-invoker</servlet-name> <url-pattern>/dwr/*</url-pattern></servlet-mapping>
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