java使用servlet实现验证码
利用servlet实现验证码主要继承httpServlet类
packagecom.zyc.demo;
importjava.awt.Color;
importjava.awt.Font;
importjava.awt.Graphics;
importjava.awt.image.BufferedImage;
importjava.io.IOException;
importjava.util.Random;
importjavax.imageio.ImageIO;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;
publicclassDrewImageextendsHttpServlet{
/**
*
*/
privatestaticfinallongserialVersionUID=1505032428319459075L;
privatefinalFontmFont=
newFont("ArialBlack",Font.PLAIN,16);
privatefinalintIMG_WIDTH=100;
privatefinalintIMG_HEIGTH=18;
privateColorgetRandColor(intfc,intbc)
{
Randomrandom=newRandom();
if(fc>255)fc=255;
if(bc>255)bc=255;
intr=fc+random.nextInt(bc-fc);
intg=fc+random.nextInt(bc-fc);
intb=fc+random.nextInt(bc-fc);
returnnewColor(r,g,b);
}
publicvoidservice(HttpServletRequestrequest,
HttpServletResponseresponse)
throwsServletException,IOException
{
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires",0);
response.setContentType("image/jpeg");
BufferedImageimage=newBufferedImage
(IMG_WIDTH,IMG_HEIGTH,BufferedImage.TYPE_INT_RGB);
Graphicsg=image.getGraphics();
Randomrandom=newRandom();
g.setColor(getRandColor(200,250));
g.fillRect(1,1,IMG_WIDTH-1,IMG_HEIGTH-1);
g.setColor(newColor(102,102,102));
g.drawRect(0,0,IMG_WIDTH-1,IMG_HEIGTH-1);
g.setColor(getRandColor(160,200));
for(inti=0;i<30;i++)
{
intx=random.nextInt(IMG_WIDTH-1);
inty=random.nextInt(IMG_HEIGTH-1);
intxl=random.nextInt(6)+1;
intyl=random.nextInt(12)+1;
g.drawLine(x,y,x+xl,y+yl);
}
g.setColor(getRandColor(160,200));
for(inti=0;i<30;i++)
{
intx=random.nextInt(IMG_WIDTH-1);
inty=random.nextInt(IMG_HEIGTH-1);
intxl=random.nextInt(12)+1;
intyl=random.nextInt(6)+1;
g.drawLine(x,y,x-xl,y-yl);
}
g.setFont(mFont);
StringsRand="";
for(inti=0;i<4;i++)
{
Stringtmp=getRandomChar();
sRand+=tmp;
g.setColor(newColor(20+random.nextInt(110)
,20+random.nextInt(110)
,20+random.nextInt(110)));
g.drawString(tmp,15*i+10,15);
}
HttpSessionsession=request.getSession(true);
session.setAttribute("rand",sRand);
//System.out.println("写入session"+sRand);
g.dispose();
ImageIO.write(image,"JPEG",response.getOutputStream());
}
privateStringgetRandomChar()
{
intrand=(int)Math.round(Math.random()*2);
longitmp=0;
charctmp='\u0000';
switch(rand)
{
case1:
itmp=Math.round(Math.random()*25+65);
ctmp=(char)itmp;
returnString.valueOf(ctmp);
case2:
itmp=Math.round(Math.random()*25+97);
ctmp=(char)itmp;
returnString.valueOf(ctmp);
default:
itmp=Math.round(Math.random()*9);
returnitmp+"";
}
}
}
下面是web.xml配置
<?xmlversion="1.0"encoding="UTF-8"?> <web-appxmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee"xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"id="WebApp_ID"version="3.0"> <display-name>IndustryDemo</display-name> <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> <servlet> <servlet-name>img</servlet-name> <servlet-class>com.zyc.demo.DrewImage</servlet-class> </servlet> <servlet-mapping> <servlet-name>img</servlet-name> <url-pattern>/img.do</url-pattern> </servlet-mapping> </web-app>
jsp文件
<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%> <% Stringpath=request.getContextPath(); StringbasePath=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN"> <html> <head> <basehref="<%=basePath%>"> <title>MyJSP'yanzhengma.jsp'startingpage</title> <metahttp-equiv="pragma"content="no-cache"> <metahttp-equiv="cache-control"content="no-cache"> <metahttp-equiv="expires"content="0"> <metahttp-equiv="keywords"content="keyword1,keyword2,keyword3"> <metahttp-equiv="description"content="Thisismypage"> <!-- <linkrel="stylesheet"type="text/css"href="styles.css"> --> </head> <body> <imgalt="验证码"src="img.do"><buttononclick="window.location.reload();">刷新</button> </body> </html>
简单实用。
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毛票票。