servlet验证码

分手后的思念是犯贱 2022-06-11 06:07 176阅读 0赞

public class AuthImageServlet extends HttpServlet     
\{       
    private static final String CONTENT\_TYPE = "text/html; charset=gb2312";     
    //设置字母的大小,大小     
    private Font mFont = new Font("Times New Roman", Font.PLAIN, 17);  
       
    public void init() throws ServletException     
    \{     
        super.init();     
    \}     
    Color getRandColor(int fc,int bc)     
    \{     
        Random random = new Random();     
        if(fc>255) fc=255;     
        if(bc>255) bc=255;     
        int r=fc+random.nextInt(bc-fc);     
        int g=fc+random.nextInt(bc-fc);     
        int b=fc+random.nextInt(bc-fc);     
        return new Color(r,g,b);     
    \}     
   
    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException     
    \{     
        response.setHeader("Pragma","No-cache");     
        response.setHeader("Cache-Control","no-cache");     
        response.setDateHeader("Expires", 0);     
        //表明生成的响应是图片     
        response.setContentType("image/jpeg");                
        int width=100, height=18;     
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE\_INT\_RGB);               
        Graphics g = image.getGraphics();     
        Random random = new Random();     
        g.setColor(getRandColor(200,250));     
        g.fillRect(1, 1, width-1, height-1);     
        g.setColor(new Color(102,102,102));     
        g.drawRect(0, 0, width-1, height-1);     
        g.setFont(mFont);       
        g.setColor(getRandColor(160,200));       
        //画随机线     
        for (int i=0;i<155;i++)     
        \{     
            int x = random.nextInt(width - 1);     
            int y = random.nextInt(height - 1);     
            int xl = random.nextInt(6) + 1;     
            int yl = random.nextInt(12) + 1;     
            g.drawLine(x,y,x + xl,y + yl);     
        \}       
        //从另一方向画随机线     
        for (int i = 0;i < 70;i++)     
        \{     
            int x = random.nextInt(width - 1);     
            int y = random.nextInt(height - 1);     
            int xl = random.nextInt(12) + 1;     
            int yl = random.nextInt(6) + 1;     
            g.drawLine(x,y,x - xl,y - yl);     
        \}       
        //生成随机数,并将随机数字转换为字母     
        String sRand="";     
        for (int i=0;i<6;i++)     
        \{     
            int itmp = random.nextInt(26) + 65;     
            char ctmp = (char)itmp;     
            sRand += String.valueOf(ctmp);     
            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));     
            g.drawString(String.valueOf(ctmp),15\*i+10,16);     
        \}       
        HttpSession session = request.getSession(true);     
        session.setAttribute("rand",sRand);     
        g.dispose();     
        ImageIO.write(image, "JPEG", response.getOutputStream());     
    \}     
    public void destroy()     
    \{     
    \}

然后在jsp中的图片上通过src="该servlet的路径"就可以了