<%@ 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(0,80,30);
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();
%>
checkcode.jsp验证码输入页面（Ajax验证提示）
<%@ 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>//用来添加图片提示输入的验证码是否正确
</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 = "";
}
function createAJAX() {
var ajax = null;
try {
ajax = new ActiveXObject("microsoft.xmlhttp");
} catch (e1) {
try {
ajax = new XMLHttpRequest();
} catch (e2) {
alert("你的浏览器不支持ajax，请更换浏览器");
}
}
return ajax;
}
}
</script>
</body>
</html>
checkcodeAction.java：action处理
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;
}
}
web.xml对struts核心过滤器的配置
<filter>
<filter-name>StrutsPrepareAndExecuteFilter</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>StrutsPrepareAndExecuteFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
struts.xml配置 action
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="myPackage" extends="json-default" namespace="/">
<action name="checkRequest" class="action.CheckcodeAction"
method="check">
</action>
</package>
</struts>