java web中图片验证码功能的简单实现方法
用户在注册网站信息的时候基本上都要数据验证码验证。那么图片验证码功能该如何实现呢?
大概步骤是:
1.在内存中创建缓存图片
2.设置背景色
3.画边框
4.写字母
5.绘制干扰信息
6.图片输出
废话不多说,直接上代码
packagecom.lsgjzhuwei.servlet.response; 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.annotation.WebServlet; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; /** *ServletimplementationclassVerificationCode */ @WebServlet(asyncSupported=true,urlPatterns={"/VerificationCode"}) publicclassVerificationCodeextendsHttpServlet{ privatestaticfinallongserialVersionUID=1L; /** *@seeHttpServlet#HttpServlet() */ publicVerificationCode(){ super(); //TODOAuto-generatedconstructorstub } /** *@seeHttpServlet#doGet(HttpServletRequestrequest,HttpServletResponseresponse) */ protectedvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{ //TODOAuto-generatedmethodstub intwidth=120; intheight=30; //创建一张内存中的缓存图片 BufferedImagebufferedImage=newBufferedImage(width,height,BufferedImage.TYPE_INT_RGB); ///背景色 //通过graphics绘制图像 Graphicsgraphics=bufferedImage.getGraphics(); //设置颜色 graphics.setColor(Color.yellow); //填充 graphics.fillRect(0,0,width,height); ///画边框 graphics.setColor(Color.blue); graphics.drawRect(0,0,width-1,height-1); //写字母 Stringcontent="ABCDEFGHIJKLMNOPQRSTUVWXYZabcedfghijklmnopqrstuvwxyz1234567890"; Randomrandom=newRandom(); //设置字体颜色 graphics.setColor(Color.red); //设置字体及大小 graphics.setFont(newFont("宋体",Font.BOLD,20)); intx=20; inty=20; for(inti=0;i<4;i++) { intindex=random.nextInt(content.length()); charletter=content.charAt(index); graphics.drawString(letter+"",x,y); x=x+20; } //绘制干扰线 intx1; intx2; inty1; inty2; graphics.setColor(Color.LIGHT_GRAY); for(inti=0;i<50;i++) { x1=random.nextInt(width); x2=random.nextInt(width); y1=random.nextInt(height); y2=random.nextInt(height); graphics.drawLine(x1,y1,x2,y2); } //将图片输出到浏览器 //将内存的图片通过浏览器输出流输出成jpg图片 ImageIO.write(bufferedImage,"jpg",response.getOutputStream()); } /** *@seeHttpServlet#doPost(HttpServletRequestrequest,HttpServletResponseresponse) */ protectedvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{ //TODOAuto-generatedmethodstub } }
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