一 验证码的由来
在web项目开发中,为了防止部分人使用自动工具(如:自动注册机)等进行批量的数据处理,在不同的功能节点部分,添加了验证码进行验证,达到对自动软件的屏蔽效果
最经典的应用如:网站注册图形验证码;接下来,通过java技术,结合servlet实现一个网站注册需要的图形验证码程序,提供大家参考。
二 实现注册页面图形验证码效果
1. 创建web项目:java_servlet_verifyimg
2. 创建自动生成图形验证码的控制器——verifyimgservlet
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package com.phome.util;
import java.awt.color;
import java.awt.font;
import java.awt.graphics2d;
import java.awt.image.bufferedimage;
import java.io.ioexception;
import java.util.random;
import javax.servlet.servletexception;
import javax.servlet.servletoutputstream;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import com.sun.image.codec.jpeg.jpegcodec;
import com.sun.image.codec.jpeg.jpegimageencoder;
public class verifyimgservlet extends httpservlet {
/**
*
*/
private static final long serialversionuid = 1l;
// 设置随机字符字典。其中不包含0,o,1,i等难以辨认的字符
public static final char [] chars = { '2' , '3' , '4' , '5' , '6' , '7' , '8' ,
'9' , 'a' , 'b' , 'c' , 'd' , 'e' , 'f' , 'g' , 'h' , 'j' , 'k' , 'l' , 'm' ,
'n' , 'p' , 'q' , 'r' , 's' , 't' , 'u' , 'v' , 'w' , 'x' , 'y' , 'z' , 'a' ,
'b' , 'c' , 'd' , 'e' , 'f' , 'g' , 'h' , 'j' , 'k' , 'l' , 'm' , 'n' , 'p' ,
'q' , 'r' , 's' , 't' , 'u' , 'v' , 'w' , 'x' , 'y' , 'z' };
public static random random = new random(); // 随机数对象
public static string getrandomstring() {
stringbuffer buffer = new stringbuffer(); // 字符串缓存
for ( int i = 0 ; i < 6 ; i++) // 六次循环获取字符
{
buffer.append(chars[random.nextint(chars.length)]); // 每次随机取一个字符
}
return buffer.tostring();
}
public static color getrandomcolor() {
return new color(random.nextint( 255 ), random.nextint( 255 ),
random.nextint( 255 ));
}
public static color getreversecolor(color c) {
return new color( 255 - c.getred(), 255 - c.getgreen(),
255 - c.getblue());
}
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
response.setcontenttype( "image/jpeg" ); // 设置输出类型 不可省略
string randomstring = getrandomstring(); // 调用生成随机字符串方法获取并接受随机字符串
request.getsession( true ).setattribute( "randomstring" , randomstring); // 将字符串存储到session中
int width = 100 ; // 图片宽度
int height = 30 ; // 图片高度
color color = getrandomcolor(); // 获取随机颜色 用于背景色
color reverse = getreversecolor(color); // 反色 用于前景色
bufferedimage bi = new bufferedimage(width, height,
bufferedimage.type_int_rgb); // 创建一个彩色图片
graphics2d g = bi.creategraphics(); // 获取绘图对象
g.setfont( new font(font.sans_serif, font.bold, 16 )); // 设置字体
g.setcolor(color); // 设置颜色
g.fillrect( 0 , 0 , width, height); // 绘制背景
g.setcolor(reverse); // 设置颜色
g.drawstring(randomstring, 18 , 20 ); // 绘制随机字符
for ( int i = 0 , n = random.nextint( 100 ); i < n; i++) // 画最多一百个噪音点
{
g.drawrect(random.nextint(width), random.nextint(height), 1 , 1 ); // 随机噪音点
}
servletoutputstream out = response.getoutputstream(); // 好像是获取输出流
jpegimageencoder encoder = jpegcodec.createjpegencoder(out); // 编码器
encoder.encode(bi); // 对图片进行编码
out.flush(); // 输出到客户端
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
this .doget(request, response);
}
}
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3. 创建注册控制器——registservlet
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package com.phome.servlet;
import java.io.ioexception;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import javax.servlet.http.httpsession;
/**
* 注册控制器
* @author zuoyi
*
*/
public class registservlet extends httpservlet{
/**
*
*/
private static final long serialversionuid = 1l;
@override
protected void doget(httpservletrequest req, httpservletresponse resp)
throws servletexception, ioexception {
this .dopost(req, resp);
}
@override
protected void dopost(httpservletrequest req, httpservletresponse resp)
throws servletexception, ioexception {
// 从session中获取注册随机验证码
httpsession session = req.getsession();
string randomstring = (string)session.getattribute( "randomstring" );
// 获取用户输入验证码
string inputrandomstring = req.getparameter( "randomstr" );
// 判断验证码通过,模拟进行注册
if (randomstring.equals(inputrandomstring)) {
req.setattribute( "resinfo" , "恭喜!注册成功!" );
} else {
req.setattribute( "resinfo" , "验证码输入有误,请检查后重新进行注册!" );
}
// 注册成功或者失败,都跳转到result.jsp页面,查看注册结果。。。
req.getrequestdispatcher( "result.jsp" ).forward(req, resp);
}
}
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4. 配置servlet
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<?xml version= "1.0" encoding= "utf-8" ?>
<web-app xmlns:xsi= "http://www.w3.org/2001/xmlschema-instance" xmlns= "http://java.sun.com/xml/ns/javaee" xsi:schemalocation= "http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id= "webapp_id" version= "3.0" >
<display-name>simg</display-name>
<!-- 配置用户注册servlet -->
<servlet>
<servlet-name>registservlet</servlet-name>
<servlet- class >com.phome.servlet.registservlet</servlet- class >
</servlet>
<servlet-mapping>
<servlet-name>registservlet</servlet-name>
<url-pattern>/regist.action</url-pattern>
</servlet-mapping>
<!-- 配置图形验证码servlet -->
<servlet>
<servlet-name>verifyimg</servlet-name>
<servlet- class >com.phome.servlet.verifyimgservlet</servlet- class >
</servlet>
<servlet-mapping>
<servlet-name>verifyimg</servlet-name>
<url-pattern>/verifyimg.action</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file> default .html</welcome-file>
<welcome-file> default .htm</welcome-file>
<welcome-file> default .jsp</welcome-file>
</welcome-file-list>
</web-app>
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5. 创建注册视图测试页面——regist.jsp
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<%@ page language= "java" import = "java.util.*" pageencoding= "gb18030" %>
<%
string path = request.getcontextpath();
string basepath = request.getscheme()+ "://" +request.getservername()+ ":" +request.getserverport()+path+ "/" ;
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" >
<html>
<head>
<base href= "<%=basepath%>" rel= "external nofollow" rel= "external nofollow" >
<title>my jsp 'index.jsp' starting page</title>
<meta http-equiv= "pragma" content= "no-cache" >
<meta http-equiv= "cache-control" content= "no-cache" >
<meta http-equiv= "expires" content= "0" >
<meta http-equiv= "keywords" content= "keyword1,keyword2,keyword3" >
<meta http-equiv= "description" content= "this is my page" >
<!--
<link rel= "stylesheet" type= "text/css" href= "styles.css" rel= "external nofollow" rel= "external nofollow" >
-->
</head>
<body>
<form action= "${pagecontext.request.contextpath}/regist.action" method= "post" >
用户名:<input type= "text" name= "username" />
<br />
密码:<input type= "text" name= "password" />
<br />
请输入验证码进行注册:
<img src= "${pagecontext.request.contextpath }/verifyimg.action" />
<input type= "text" name= "randomstr" />
<br />
<input type= "submit" value= "regist" />
</form>
</body>
</html>
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5.1 创建注册结果页面——result.jsp
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<%@ page language= "java" import = "java.util.*" pageencoding= "gb18030" %>
<%
string path = request.getcontextpath();
string basepath = request.getscheme()+ "://" +request.getservername()+ ":" +request.getserverport()+path+ "/" ;
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" >
<html>
<head>
<base href= "<%=basepath%>" rel= "external nofollow" rel= "external nofollow" >
<title>my jsp 'index.jsp' starting page</title>
<meta http-equiv= "pragma" content= "no-cache" >
<meta http-equiv= "cache-control" content= "no-cache" >
<meta http-equiv= "expires" content= "0" >
<meta http-equiv= "keywords" content= "keyword1,keyword2,keyword3" >
<meta http-equiv= "description" content= "this is my page" >
<!--
<link rel= "stylesheet" type= "text/css" href= "styles.css" rel= "external nofollow" rel= "external nofollow" >
-->
</head>
<body>
${requestscope.resinfo }
</body>
</html>
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6.测试
(1)a.打开浏览器,输入测试地址:http://localhost:8080/java_servlet_verifyimg;出现如下图所示页面
b.输入注册账号、密码和验证码后点击regist提交
c.测试结果,跳转会注册页面,提示注册成功
(2)打开注册页面
输入错误注册码
测试结果页面
over!
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:http://blog.csdn.net/muwenbin_flex/article/details/19766865