ajax验证码检测

1、验证码文件

<%@ page language="java" pageEncoding="UTF-8"%>

<%@ page contentType="image/jpeg"  import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>

<%!

    public Color getColor(){

        Random random = new Random();

        int r = random.nextInt(256);//0-255

        int g = random.nextInt(256);

        int b = random.nextInt(256);

        return new Color(r,g,b);

    }

    public String getNum(){

        String str = "";

        Random random = new Random();

        for(int i=0;i<4;i++){

            str += random.nextInt(10);//0-9

        }

        return str;

    }

%>

<%

    response.setHeader("pragma", "mo-cache");

    response.setHeader("cache-control", "no-cache");

    response.setDateHeader("expires", 0);

    BufferedImage image = new BufferedImage(80,30,BufferedImage.TYPE_INT_RGB);

    Graphics g = image.getGraphics();

    g.setColor(new Color(200,200,200));

    g.fillRect(0,0,80,30);

    for (int i = 0; i < 30; i++) {

        Random random = new Random();

        int x = random.nextInt(80);

        int y = random.nextInt(30);

        int xl = random.nextInt(x+10);

        int yl = random.nextInt(y+10);

        g.setColor(getColor());

        g.drawLine(x, y, x + xl, y + yl);

    }

    g.setFont(new Font("serif", Font.BOLD,16));

    g.setColor(Color.BLACK);

    String checkNum = getNum();//"2525"

    StringBuffer sb = new StringBuffer();

    for(int i=0;i<checkNum.length();i++){

        sb.append(checkNum.charAt(i)+" ");//"2 5 2 5"

    }

    g.drawString(sb.toString(),15,20);

    session.setAttribute("CHECKNUM",checkNum);//2525

    ImageIO.write(image,"jpeg",response.getOutputStream());

    out.clear();

    out = pageContext.pushBody();

%>

2、验证HTML文件

<%@ page language="java" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <title>验证码检查</title>

    <script type="text/javascript" src="js/ajax.js"></script>

  </head>

  <body>

    <form>

        <table border="0" align="center">

            <tr>

                <th>验证码：</th>

                <td><input size="2" type="text" name="checkcode" id="checkcodeID" maxlength="4"/></td>

                <td><img src="01_image.jsp"/>

                <td id="res"></td>

            </tr>

        </table>

    </form>

    <script type="text/javascript">

        //去掉二边的空格

        function trim(str){"  zhaojun  "

            str = str.replace(/^\s*/,"");//"zhaojun  "

            str = str.replace(/\s*$/,"");//"zhaojun"

            return str;

        }

    </script>

    <script type="text/javascript">

        document.getElementById("checkcodeID").onkeyup = function(){

            var checkcode = this.value;

            checkcode = trim(checkcode);//2525

            if(checkcode.length == 4){

                //NO1)

                var ajax = createAJAX();

                //NO2)

                var method = "POST";

                var url = "${pageContext.request.contextPath}/checkRequest?time="+new Date().getTime();

                ajax.open(method,url);

                //NO3)

                ajax.setRequestHeader("content-type","application/x-www-form-urlencoded");

                //NO4)

                var content = "checkcode=" + checkcode;

                ajax.send(content);

                //--------------------------------------------------------等待

                //NO5)

                ajax.onreadystatechange = function(){

                    if(ajax.readyState == 4){

                        if(ajax.status == 200){

                            //NO6)

                            var tip = ajax.responseText;

                            //NO7)

                            var img = document.createElement("img");

                            img.src = tip;

                            img.style.width = "14px";

                            img.style.height = "14px";

                            var td = document.getElementById("res");

                            td.innerHTML = "";

                            td.appendChild(img);

                        }

                    }

                }

            }else{

                //清空图片

                var td = document.getElementById("res");

                td.innerHTML = "";

            }

        }

    </script>    

  </body>

</html>

3、java文件

package cn.itcast.javaee.js.checkcode;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

/**

 * 验证码检查

 * @author AdminTC

 */

public class CheckcodeAction extends ActionSupport{

    //客户端验证码

    private String checkcode;//2525

    //注入客户端验证码

    public void setCheckcode(String checkcode) {

        this.checkcode = checkcode;

    }

    /**

     * 验证

     */

    public String check() throws Exception {

        //图片路径

        String tip = "images/MsgError.gif";

        //从服务器获取session中的验证码

        String checkcodeServer = (String) ActionContext.getContext().getSession().get("CHECKNUM");

        //将客户端的验证码与服务端的验证码进行比较

        if(checkcode.equals(checkcodeServer)){

            tip = "images/MsgSent.gif";

        }

        //以IO流的方式将tip变量的值输出到AJAX异步对象中

        HttpServletResponse response = ServletActionContext.getResponse();

        response.setContentType("text/html;charset=UTF-8");

        PrintWriter pw = response.getWriter();

        pw.write(tip);

        pw.flush();

        pw.close();

        //以下方式不是最好的，但可以完成AJAX异步交互

        return null;

    }

}

4、struts文件

        <action

            name="checkRequest"

            class="cn.itcast.javaee.js.checkcode.CheckcodeAction"

            method="check">

        </action>

巴特西

ajax验证码检测

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