[url]
http://hi.baidu.com/homefovever/blog/item/49d1f900c49e4782e850cd38.html[/url]
PersonDAO.java
http://hi.baidu.com/homefovever/blog/item/49d1f900c49e4782e850cd38.html[/url]
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" οnchange="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>
