Javaweb开发之验证码制作

javaweb开发之制作简单验证码

使用xml对页面进行配置，验证码模块具体配置如下，code.jhtml为验证码存放位置

<servlet><servlet-name>CodeAction</servlet-name><servlet-class>campsg.qunawan.action.CodeAction</servlet-class></servlet><servlet-mapping><servlet-name>CodeAction</servlet-name><url-pattern>/code.jhtml</url-pattern></servlet-mapping>

html页面中，页面脚本如下（该页面为登录页面，不同于code.jhtml）

<li><span class="identifying"><img width="120px" height="40px" src="/PRJ_WTP_JEE_005/code.jhtml" onclick="javascript:this.src='/PRJ_WTP_JEE_005/code.jhtml?id='+new Date().getMilliseconds()"></span><input type="text" name="code" id="ident" class="text identify" value="验证码" /></li>

其中的onclick()响应是为了保证每次刷新的能获取到正确可用的路径

制作验证码另外还需如下准备工作：制作字符库，颜色库，字体库（为了方便，统一成了一样），图像长、宽度等信息

在src目录下的包中，新建一个类，暂且命名为Constant，将所需信息写入

public class Constants {// 验证码的字体库public static Font[] codeFont = { new Font("Times New Roman", Font.PLAIN, 30),new Font("Times New Roman", Font.PLAIN, 30), new Font("Times New Roman", Font.PLAIN, 30),new Font("Times New Roman", Font.PLAIN, 30) };// 验证码数字颜色库public static Color[] color = { Color.BLACK, Color.RED, Color.DARK_GRAY, Color.BLUE };// 验证码的字符库public static final String IMAGE_CHAR = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";// 验证码的宽度public static final Integer IMAGE_WIDTH = 120;// 验证码的高度public static final Integer IMAGE_HEIGHT = 40;}

在src目录的包下新建一个类，暂且命名为CodeAction，使其继承HttpServlet类，写入生成随机验证码代码

public class CodeAction extends HttpServlet{private static final long serialVersionUID = -175449573736935176L;private String codeNumbers="";@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("执行CodeAction方法");BufferedImage image=new BufferedImage(Constants.IMAGE_WIDTH, Constants.IMAGE_HEIGHT,BufferedImage.TYPE_INT_RGB);Graphics2D g=(Graphics2D) image.getGraphics();g.setColor(createRandomColor(200,300));g.fillRect(0, 0, Constants.IMAGE_WIDTH, Constants.IMAGE_HEIGHT);/** * 画出验证码字符 */for(int i=0;i<4;i++){drawString(g, i);}System.out.println("生成验证码："+this.codeNumbers);//绘制干扰线drawNoiseLine(g, 5);this.codeNumbers="";ServletOutputStream sos=response.getOutputStream();ImageIO.write(image, "GIF", sos);sos.close();}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubdoGet(request,response);}/** * 绘制验证码字符串 * @param g 图层 * @param i 第几位字符 */private void drawString(Graphics2D g,int i) {Random random=new Random();Integer j=random.nextInt(Constants.IMAGE_CHAR.length());String number=Constants.IMAGE_CHAR.substring(j, j+1);g.setFont(Constants.codeFont[i]);g.setColor(Constants.color[i]);g.drawString(number, 15*i+20, 30);this.codeNumbers+=number;}/** * 随机生成图片背景颜色 * @param bcf 最小值 * @param bcl 最大值 * @return RGB颜色 */private Color createRandomColor(int bcf,int bcl ) {Color color=null;boolean flag=true;while(flag){int r=bcf+new Random().nextInt(bcl-bcf);int g=bcf+new Random().nextInt(bcl-bcf);int b=bcf+new Random().nextInt(bcl-bcf);if((r>=0&&r<=255)&&(g>=0&&g<=255)&&(b>=0&&b<=255)){color=new Color(r,g,b);flag=false;}}return color;}/** * 绘制干扰线条 * @param g 图层 * @param NoiseLineNumber 干扰线数量 */private void drawNoiseLine(Graphics2D g,int NoiseLineNumber) {g.setColor(createRandomColor(100,250));int x1=0,y1=0,x2=0,y2=0;for(int i=0;i<NoiseLineNumber;i++){x1=(int) (1+(Math.random()*120));y1=(int) (1+(Math.random()*40));x2=(int) (1+(Math.random()*120));y2=(int) (1+(Math.random()*40));g.setStroke(new BasicStroke(2, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND));g.drawLine(x1, y1, x2, y2);}    }}

结果如下