struts中验证码的实现

public class ValidateCodeAction {private ByteArrayInputStream byteArrayInputStream;public ByteArrayInputStream getByteArrayInputStream() {return byteArrayInputStream;}public void setByteArrayInputStream(ByteArrayInputStream byteArrayInputStream) {this.byteArrayInputStream = byteArrayInputStream;}public String execute() {try {setByteArrayInputStream(createValidateCodeImage());} catch (Exception e) {e.printStackTrace();}return "success";}/** * 产生一个验证码图片 *  * @return ByteArrayInputStream */private ByteArrayInputStream createValidateCodeImage() {BufferedImage bufferedImage = new BufferedImage(100, 30,BufferedImage.TYPE_INT_RGB);Graphics g = bufferedImage.getGraphics();g.setColor(Color.white);g.fillRect(0, 0, 100, 30);drawBackground(g);// 绘制图片背景drawValidateCode(g);// 绘制生成的验证码到图片上ByteArrayInputStream byteArrayInputStream = null;ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();try {ImageIO.write(bufferedImage, "JPEG", byteArrayOutputStream);} catch (IOException e) {e.printStackTrace();System.out.println("产生一个验证码图片");}byte[] buf = byteArrayOutputStream.toByteArray();byteArrayInputStream = new ByteArrayInputStream(buf);try {byteArrayOutputStream.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return byteArrayInputStream;}/** * 绘制图片背景 *  * @param g * */private void drawBackground(Graphics g) {Random random = new Random();int randomX, randomY;for (int i = 0; i < random.nextInt(50)+500; ++i) {g.setColor(new Color(random.nextInt(255), random.nextInt(255),random.nextInt(255)));randomX = random.nextInt(100);randomY = random.nextInt(30);g.drawLine(randomX, randomY, randomX, randomY);}}/** * 产生随机验证码,并存入Session发送至服务器端 *  * @return String * */private String createCode() {Random random = new Random();StringBuffer sb = new StringBuffer("ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890");// 验证码范围StringBuffer code = new StringBuffer();int codeLength = 4;// 验证码长度for (int i = 0; i < codeLength; ++i) {code.append(sb.charAt(random.nextInt(sb.length())));}// 将验证码存入SessionServletActionContext.getRequest().getSession().setAttribute(Constant.VALIDATE_CODE, code.toString());return code.toString();}/** * 将验证码绘制到图片上 *  * @param g * */private void drawValidateCode(Graphics g) {String code = createCode();Random random = new Random();int x = 10, y = 0;g.setFont(new Font("Times New Roman", Font.PLAIN, 30));for (int i = 0; i < code.length(); ++i) {y =30-random.nextInt(10);g.setColor(new Color(random.nextInt(150), random.nextInt(150),random.nextInt(150)));g.drawString(code.substring(i, i + 1), x, y);x += 20;}}}

注意在配置文件中这样配置：

<!-- 验证码解析XML --><action name="validateCodeAction" class="com.weiyi.exam.web.action.ValidateCodeAction"><result name="success" type="stream"><param name="contentType">image/jpeg</param><param name="inputName">byteArrayInputStream</param></result></action>

每次需要验证码的时候，只要请求此Action