servlet验证码-蒲公英云

servlet验证码

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()     
\{     
\}