jquery实现无刷新验证码的简单实例
1.思路:
页面上的验证码图片是servlet,采用jquery实现异步校验信息
2.所用到的文件
VerifyCodeServlet.java --用于生成图片的servlet
ResultServlet.java --用于校验验证码正确性的servlet
verifyCode.js --校验的js文件
jquery.js --jquery包里的源文件
verifyCode.jsp --页面
3.代码
VerifyCodeServlet.java
Java代码
importjava.awt.Color; importjava.awt.Font; importjava.awt.Graphics2D; importjava.awt.image.BufferedImage; importjava.util.Random; importjavax.imageio.ImageIO; importjavax.servlet.ServletException; importjavax.servlet.ServletOutputStream; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; importjavax.servlet.http.HttpSession; publicclassVerifyCodeServletextendsHttpServlet{ //验证码图片的宽度。 privateintwidth=60; //验证码图片的高度。 privateintheight=20; //验证码字符个数 privateintcodeCount=4; privateintx=0; //字体高度 privateintfontHeight; privateintcodeY; char[]codeSequence={'A','B','C','D','E','F','G','H','I','J', 'K','L','M','N','O','P','Q','R','S','T','U','V','W', 'X','Y','Z','0','1','2','3','4','5','6','7','8','9'}; /** *初始化验证图片属性 */ publicvoidinit()throwsServletException{ //从web.xml中获取初始信息 //宽度 StringstrWidth=this.getInitParameter("width"); //高度 StringstrHeight=this.getInitParameter("height"); //字符个数 StringstrCodeCount=this.getInitParameter("codeCount"); //将配置的信息转换成数值 try{ if(strWidth!=null&&strWidth.length()!=0){ width=Integer.parseInt(strWidth); } if(strHeight!=null&&strHeight.length()!=0){ height=Integer.parseInt(strHeight); } if(strCodeCount!=null&&strCodeCount.length()!=0){ codeCount=Integer.parseInt(strCodeCount); } }catch(NumberFormatExceptione){ } x=width/(codeCount+1); fontHeight=height-2; codeY=height-4; } protectedvoidservice(HttpServletRequestreq,HttpServletResponseresp) throwsServletException,java.io.IOException{ //定义图像buffer BufferedImagebuffImg=newBufferedImage(width,height, BufferedImage.TYPE_INT_RGB); Graphics2Dg=buffImg.createGraphics(); //创建一个随机数生成器类 Randomrandom=newRandom(); //将图像填充为白色 g.setColor(Color.WHITE); g.fillRect(0,0,width,height); //创建字体,字体的大小应该根据图片的高度来定。 Fontfont=newFont("Fixedsys",Font.PLAIN,fontHeight); //设置字体。 g.setFont(font); //画边框。 g.setColor(Color.BLACK); g.drawRect(0,0,width-1,height-1); //随机产生160条干扰线,使图象中的认证码不易被其它程序探测到。 g.setColor(Color.BLACK); for(inti=0;i<160;i++){ intx=random.nextInt(width); inty=random.nextInt(height); intxl=random.nextInt(12); intyl=random.nextInt(12); g.drawLine(x,y,x+xl,y+yl); } //randomCode用于保存随机产生的验证码,以便用户登录后进行验证。 StringBufferrandomCode=newStringBuffer(); intred=0,green=0,blue=0; //随机产生codeCount数字的验证码。 for(inti=0;i<codeCount;i++){ //得到随机产生的验证码数字。 StringstrRand=String.valueOf(codeSequence[random.nextInt(36)]); //产生随机的颜色分量来构造颜色值,这样输出的每位数字的颜色值都将不同。 red=random.nextInt(255); green=random.nextInt(255); blue=random.nextInt(255); //用随机产生的颜色将验证码绘制到图像中。 g.setColor(newColor(red,green,blue)); g.drawString(strRand,(i+1)*x,codeY); //将产生的四个随机数组合在一起。 randomCode.append(strRand); } //将四位数字的验证码保存到Session中。 HttpSessionsession=req.getSession(); session.setAttribute("validateCode",randomCode.toString()); //禁止图像缓存。 resp.setHeader("Pragma","no-cache"); resp.setHeader("Cache-Control","no-cache"); resp.setDateHeader("Expires",0); resp.setContentType("image/jpeg"); //将图像输出到Servlet输出流中。 ServletOutputStreamsos=resp.getOutputStream(); ImageIO.write(buffImg,"jpeg",sos); sos.close(); } } importjava.awt.Color; importjava.awt.Font; importjava.awt.Graphics2D; importjava.awt.image.BufferedImage; importjava.util.Random; importjavax.imageio.ImageIO; importjavax.servlet.ServletException; importjavax.servlet.ServletOutputStream; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; importjavax.servlet.http.HttpSession; publicclassVerifyCodeServletextendsHttpServlet{ //验证码图片的宽度。 privateintwidth=60; //验证码图片的高度。 privateintheight=20; //验证码字符个数 privateintcodeCount=4; privateintx=0; //字体高度 privateintfontHeight; privateintcodeY; char[]codeSequence={'A','B','C','D','E','F','G','H','I','J', 'K','L','M','N','O','P','Q','R','S','T','U','V','W', 'X','Y','Z','0','1','2','3','4','5','6','7','8','9'}; /** *初始化验证图片属性 */ publicvoidinit()throwsServletException{ //从web.xml中获取初始信息 //宽度 StringstrWidth=this.getInitParameter("width"); //高度 StringstrHeight=this.getInitParameter("height"); //字符个数 StringstrCodeCount=this.getInitParameter("codeCount"); //将配置的信息转换成数值 try{ if(strWidth!=null&&strWidth.length()!=0){ width=Integer.parseInt(strWidth); } if(strHeight!=null&&strHeight.length()!=0){ height=Integer.parseInt(strHeight); } if(strCodeCount!=null&&strCodeCount.length()!=0){ codeCount=Integer.parseInt(strCodeCount); } }catch(NumberFormatExceptione){ } x=width/(codeCount+1); fontHeight=height-2; codeY=height-4; } protectedvoidservice(HttpServletRequestreq,HttpServletResponseresp) throwsServletException,java.io.IOException{ //定义图像buffer BufferedImagebuffImg=newBufferedImage(width,height, BufferedImage.TYPE_INT_RGB); Graphics2Dg=buffImg.createGraphics(); //创建一个随机数生成器类 Randomrandom=newRandom(); //将图像填充为白色 g.setColor(Color.WHITE); g.fillRect(0,0,width,height); //创建字体,字体的大小应该根据图片的高度来定。 Fontfont=newFont("Fixedsys",Font.PLAIN,fontHeight); //设置字体。 g.setFont(font); //画边框。 g.setColor(Color.BLACK); g.drawRect(0,0,width-1,height-1); //随机产生160条干扰线,使图象中的认证码不易被其它程序探测到。 g.setColor(Color.BLACK); for(inti=0;i<160;i++){ intx=random.nextInt(width); inty=random.nextInt(height); intxl=random.nextInt(12); intyl=random.nextInt(12); g.drawLine(x,y,x+xl,y+yl); } //randomCode用于保存随机产生的验证码,以便用户登录后进行验证。 StringBufferrandomCode=newStringBuffer(); intred=0,green=0,blue=0; //随机产生codeCount数字的验证码。 for(inti=0;i<codeCount;i++){ //得到随机产生的验证码数字。 StringstrRand=String.valueOf(codeSequence[random.nextInt(36)]); //产生随机的颜色分量来构造颜色值,这样输出的每位数字的颜色值都将不同。 red=random.nextInt(255); green=random.nextInt(255); blue=random.nextInt(255); //用随机产生的颜色将验证码绘制到图像中。 g.setColor(newColor(red,green,blue)); g.drawString(strRand,(i+1)*x,codeY); //将产生的四个随机数组合在一起。 randomCode.append(strRand); } //将四位数字的验证码保存到Session中。 HttpSessionsession=req.getSession(); session.setAttribute("validateCode",randomCode.toString()); //禁止图像缓存。 resp.setHeader("Pragma","no-cache"); resp.setHeader("Cache-Control","no-cache"); resp.setDateHeader("Expires",0); resp.setContentType("image/jpeg"); //将图像输出到Servlet输出流中。 ServletOutputStreamsos=resp.getOutputStream(); ImageIO.write(buffImg,"jpeg",sos); sos.close(); } }
ResultServlet.java
Java代码
importjava.io.IOException; importjava.io.PrintWriter; importjavax.servlet.ServletException; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; publicclassResultServletextendsHttpServlet{ /** *ThedoGetmethodoftheservlet.<br> * *Thismethodiscalledwhenaformhasitstagvaluemethodequalstoget. * *@paramrequesttherequestsendbytheclienttotheserver *@paramresponsetheresponsesendbytheservertotheclient *@throwsServletExceptionifanerroroccurred *@throwsIOExceptionifanerroroccurred */ publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{ doPost(request,response); } /** *ThedoPostmethodoftheservlet.<br> * *Thismethodiscalledwhenaformhasitstagvaluemethodequalstopost. * *@paramrequesttherequestsendbytheclienttotheserver *@paramresponsetheresponsesendbytheservertotheclient *@throwsServletExceptionifanerroroccurred *@throwsIOExceptionifanerroroccurred */ publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{ response.setContentType("text/html;charset=utf-8"); StringvalidateC=(String)request.getSession().getAttribute("validateCode"); StringveryCode=request.getParameter("c"); PrintWriterout=response.getWriter(); if(veryCode==null||"".equals(veryCode)){ out.println("验证码为空"); }else{ if(validateC.equals(veryCode)){ out.println("验证码正确"); }else{ out.println("验证码错误"); } } out.flush(); out.close(); } } importjava.io.IOException; importjava.io.PrintWriter; importjavax.servlet.ServletException; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; publicclassResultServletextendsHttpServlet{ /** *ThedoGetmethodoftheservlet.<br> * *Thismethodiscalledwhenaformhasitstagvaluemethodequalstoget. * *@paramrequesttherequestsendbytheclienttotheserver *@paramresponsetheresponsesendbytheservertotheclient *@throwsServletExceptionifanerroroccurred *@throwsIOExceptionifanerroroccurred */ publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{ doPost(request,response); } /** *ThedoPostmethodoftheservlet.<br> * *Thismethodiscalledwhenaformhasitstagvaluemethodequalstopost. * *@paramrequesttherequestsendbytheclienttotheserver *@paramresponsetheresponsesendbytheservertotheclient *@throwsServletExceptionifanerroroccurred *@throwsIOExceptionifanerroroccurred */ publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{ response.setContentType("text/html;charset=utf-8"); StringvalidateC=(String)request.getSession().getAttribute("validateCode"); StringveryCode=request.getParameter("c"); PrintWriterout=response.getWriter(); if(veryCode==null||"".equals(veryCode)){ out.println("验证码为空"); }else{ if(validateC.equals(veryCode)){ out.println("验证码正确"); }else{ out.println("验证码错误"); } } out.flush(); out.close(); } }
verifyCode.js
Js代码
functionchangeImg(){ varimgSrc=$("#imgObj"); varsrc=imgSrc.attr("src"); imgSrc.attr("src",chgUrl(src)); } //时间戳 //为了使每次生成图片不一致,即不让浏览器读缓存,所以需要加上时间戳 functionchgUrl(url){ vartimestamp=(newDate()).valueOf(); url=url.substring(0,17); if((url.indexOf("&")>=0)){ url=url+"×tamp="+timestamp; }else{ url=url+"?timestamp="+timestamp; } returnurl; } functionisRightCode(){ varcode=$("#veryCode").attr("value"); code="c="+code; $.ajax({ type:"POST", url:"resultServlet", data:code, success:callback }); } functioncallback(data){ $("#info").html(data); } functionchangeImg(){ varimgSrc=$("#imgObj"); varsrc=imgSrc.attr("src"); imgSrc.attr("src",chgUrl(src)); } //时间戳 //为了使每次生成图片不一致,即不让浏览器读缓存,所以需要加上时间戳 functionchgUrl(url){ vartimestamp=(newDate()).valueOf(); url=url.substring(0,17); if((url.indexOf("&")>=0)){ url=url+"×tamp="+timestamp; }else{ url=url+"?timestamp="+timestamp; } returnurl; } functionisRightCode(){ varcode=$("#veryCode").attr("value"); code="c="+code; $.ajax({ type:"POST", url:"resultServlet", data:code, success:callback }); } functioncallback(data){ $("#info").html(data); }
verifyCode.jsp
Html代码
<%@pagelanguage="java"contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPEhtmlPUBLIC"-//W3C//DTDHTML4.01Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <metahttp-equiv="Content-Type"content="text/html;charset=UTF-8"> <scripttype="text/javascript"src="js/verifyCode.js"></script> <scripttype="text/javascript"src="js/jquery.js"></script> <title>testverifycode</title> </head> <body> <inputid="veryCode"name="veryCode"type="text"/> <imgid="imgObj"alt=""src="verifyCodeServlet"/> <ahref="#"onclick="changeImg()">换一张</a> <inputtype="button"value="验证"onclick="isRightCode()"/> <divid="info"></div> </body> </html>
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