简单的Ajax+Servlet表单数据验证-技术开发专区

简单的Ajax+Servlet表单数据验证

作者：phpcms 编辑： ITPUB实习编辑 2006-11-20 16:20

【IT168技术文档】
一、用户注册的JSP页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<head>
 <META http-equiv=Content-Type content="text/html; charset=UTF-8">
</head>
<script language="javascript">

 var XMLHttpReq;  //创建XMLHttpRequest对象         
   function createXMLHttpRequest() {  
    if(window.XMLHttpRequest) { //Mozilla 浏览器   
   XMLHttpReq = new XMLHttpRequest();  }  
   else if (window.ActiveXObject) { // IE浏览器  
    try {    XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");   
    } catch (e) {   
    try {     XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");    
    } catch (e) {}   }  } } //发送请求函数
   function sendRequest(url) {  
   createXMLHttpRequest();  
   XMLHttpReq.open("GET", url, true);  
    XMLHttpReq.onreadystatechange = processResponse;//指定响应函数  
    XMLHttpReq.send(null);  // 发送请求 } // 处理返回信息函数    
   function processResponse() {     
   if (XMLHttpReq.readyState == 4) { // 判断对象状态         
   if (XMLHttpReq.status == 200) { // 信息已经成功返回，开始处理信息             
   var res=XMLHttpReq.responseXML.getElementsByTagName("res")[0].firstChild.data;     
           window.alert(res);                            
    } else { //页面不正常               
    window.alert("您所请求的页面有异常。");           
    }        }    } // 注册函数    
  function signUp() {  
   var uname = document.myform.uname.value;  
   var psw = document.myform.psw.value;  
   var psw2 = document.myform.psw2.value; 
   if(uname=="") {   window.alert("用户名不能为空。");   
   document.myform.uname.focus();   return false;  }  
   else if(psw!=psw2) {   window.alert("两次输入密码不同。");  
   document.myform.psw.focus();   return false;  }  else {   
   sendRequest('signUp?uname='+ uname + '&psw=' + psw);  } }

二、处理AJAX请求的servlet

package classmate;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class SignUpAction extends HttpServlet ...{
   public void init(ServletConfig config) throws ServletException ...{
  }
    /**//*
     *  处理<GET> 请求方法.
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException ...{
     //设置接收信息的字符集
     request.setCharacterEncoding("UTF-8");
     //接收浏览器端提交的信息
  String uname = request.getParameter("uname");
  String psw = request.getParameter("psw");
  //设置输出信息的格式及字符集        
        response.setContentType("text/xml; charset=UTF-8");
        response.setHeader("Cache-Control", "no-cache");
        //创建输出流对象
        PrintWriter out = response.getWriter();
        //依据验证结果输出不同的数据信息
        out.println("<response>");

        //数据库操作
        DB db = new DB();
  ResultSet rs;
  int insRes = 0;
        String strSql=null;
        //判断用户名是否重复
        strSql = "select * from classuser where username='"
   + uname + "'";
  rs = db.executeQuery(strSql);
  boolean bnoRepeat = false;
  try ...{
   if ( !rs.next()) ...{
    bnoRepeat = true;
   }
  } catch (SQLException e) ...{
   e.printStackTrace();
  }
        //用户名不重复,插入记录
  if (bnoRepeat)...{
            strSql = "Insert Into classuser values('"+ uname + "','" + psw + "')";
   insRes = db. executeUpdate(strSql);
        }
        if(!bnoRepeat)...{
   out.println("<res>" + "注册失败!用户名已存在，重新输入用户名" + "</res>");
  }else if(insRes>0)...{
   out.println("<res>" + "注册成功！" + "</res>");
  }else...{
   out.println("<res>" + "注册失败！" + "</res>");
  }

  out.println("</response>");
  out.close();
    }
}

【IT168技术文档】
三、数据库操作类：

package classmate;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DB ...{
 Connection connect = null;
 ResultSet rs = null;
 public DB() ...{
  try ...{
   Class.forName("org.gjt.mm.mysql.Driver");  //设置驱动程序类型  
  }
  catch(java.lang.ClassNotFoundException e) ...{
   e.printStackTrace();
  }
 }
 //执行查询语句的方法
 public ResultSet executeQuery(String sql) ...{
  try ...{
//建立与数据库服务器的连接
     onnect = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test1", "root", "");
    <br>     
   Statement stmt = connect.createStatement(
     ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
   rs = stmt.executeQuery(sql);//执行指定的数据查询语句
  }
  catch(SQLException ex) ...{
   ex.printStackTrace();
  }
  return rs;
 }
    //执行增、删改语句的方法
 public int executeUpdate(String sql) ...{
  int result = 0;
  try ...{
   connect = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test1", "root", "");
   Statement stmt = connect.createStatement();
   result = stmt.executeUpdate(sql);//执行指定的数据操作语句
  }
  catch(SQLException ex) ...{
   System.err.println(ex.getMessage());
  }
  return result;
 }
 //关闭数据库连接的方法
 public void close()...{
  if(connect!=null)...{
   try...{
    connect.close();
    connect = null;
   }catch(SQLException ex) ...{
    System.err.println(ex.getMessage());
   }
  }
 }

}

四、web.xml文件中配置servlet

<?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">

<servlet>
<servlet-name>ms1</servlet-name>
<servlet-class>classmate.SignUpAction</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>ms1</servlet-name>
<url-pattern>/signUp</url-pattern>
</servlet-mapping>

<!-- The Welcome File List -->
<welcome-file-list>
<welcome-file>signUp.jsp</welcome-file>
</welcome-file-list>
</web-app>

</script>
<body vLink="#006666" link="#003366" bgColor="#E0F0F8">
  <img height="33" src="enter.gif" width="148">
  <form action="" method="post" name="myform">
    用户名： <input size="15" name="uname"><p>
    密  码： <input type="password" size="15" name="psw"><p>
    重输密码： <input type="password" size="20" name="psw2"><p>
    <input type="button" value="注册" on click="signUp()" >
  </form>


</body>

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