驗證碼的生成,並且“看不清,換一張”
阿新 • • 發佈:2019-01-01
public class AuthImg extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=UTF-8"; private Font mFont; public AuthImg() { mFont = new Font("Times New Roman", 0, 18); } public void init() throws ServletException { } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String authCode = genAuthCode(4); AuthCodeCookie authCodeCookie = new AuthCodeCookie(request, response); authCodeCookie.addAuthCode(authCode);//儲存驗證碼到cookies response.setContentType("image/jpeg"); javax.servlet.ServletOutputStream out = response.getOutputStream(); int width = 60; int height = 20; BufferedImage image = new BufferedImage(width, height, 1); Graphics gra = image.getGraphics(); Random random = new Random(); gra.setColor(getRandColor(200, 250)); gra.fillRect(1, 1, width, height); gra.setColor(getRandColor(160, 200)); for (int i = 0; i < 155; i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); gra.drawLine(x, y, x + xl, y + yl); } gra.setFont(mFont); for (int i = 0; i < 4; i++) { char c = authCode.charAt(i); gra.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110))); gra.drawString(String.valueOf(c), 13 * i + 6, 16); } gra.dispose(); ImageIO.write(image, "JPEG", out); } 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 String genAuthCode(int length) { if (length < 1) return null; String strChars[] = { "1", "2", "3", "4", "5", "6", "7", "8", "9" }; StringBuffer strPassword = new StringBuffer(); int nRand = (int) Math.round(Math.random() * 100D); for (int i = 0; i < length; i++) { nRand = (int) Math.round(Math.random() * 100D); strPassword.append(strChars[nRand % (strChars.length - 1)]); } return strPassword.toString(); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } public void destroy() { } }
html:
function refresh() {
var img = document.getElementById("checkCodeImg");
now = new Date();
img.src = "authimg?code="+now.getTime();
}
<IMG height=18 src='authimg' id="checkCodeImg" >
<a href="#" onclick="javascript:refresh();">看不清,換一張</a>
web.xml:
<servlet>
<servlet-name>authimg</servlet-name>
<servlet-class>com.worthtech.app.servlet.AuthImg</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>authimg</servlet-name>
<url-pattern>/authimg</url-pattern>
</servlet-mapping>