char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
public void getCode(HttpServletRequest req, HttpServletResponse resp) throws Exception {
int width = 80;// 定義圖檔的width
int height = 30;// 定義圖檔的height
int fontHeight = 25; // 字型
double rate=1.3;
StringBuffer randomCode = new StringBuffer();
Random random = new Random();
// 定義圖像buffer
BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics gd = buffImg.getGraphics();
// 随機産生codeCount數字的驗證碼。
for (int i = 0; i < 4; i++) {
// 得到随機産生的驗證碼數字。
String strRand = String.valueOf(codeSequence[random.nextInt(36)]);
// 将産生的四個随機數組合在一起。
randomCode.append(strRand);
}
//居中顯示
// 将圖像填充為白色
gd.setColor(Color.WHITE);
gd.fillRect(0, 0, width, height);
// 建立字型,字型的大小應該根據圖檔的高度來定。
Font font = new Font("Consolas", Font.PLAIN, fontHeight);
// 設定字型。
gd.setFont(font);
// 畫邊框。
gd.setColor(Color.WHITE);
gd.drawRect(0, 0, width - 1, height - 1);
// 驗證碼
String numberCode = randomCode.toString();//RandomCodeUtils.getNumberCode();
setValidateCodeColor(numberCode, width,height, rate, gd);
// 設定redis緩存
//this.setCodeCache(req, numberCode);
// 禁止圖像緩存。
resp.setHeader("Pragma", "no-cache");
resp.setHeader("Cache-Control", "no-cache");
resp.setDateHeader("Expires", 0);
resp.setContentType("image/jpeg");
// 将圖像輸出到Servlet輸出流中。
ServletOutputStream sos = resp.getOutputStream();
ImageIO.write(buffImg, "jpeg", sos);
sos.close();
}
private void setValidateCodeColor(String str,int width,int height,double rate,Graphics g){
int x=(int)(width/2-rate*g.getFontMetrics().stringWidth(str)/2);
int y=height/2+g.getFontMetrics().getHeight()/3;
String tempStr = new String();
int orgStringWight=g.getFontMetrics().stringWidth(str);
int orgStringLength=str.length();
int tempx=x;
int tempy=y;
int red = 0, green = 0, blue = 0;
Random random = new Random();
while(str.length()>0)
{
tempStr=str.substring(0, 1);
str=str.substring(1, str.length());
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
g.setColor(new Color(red, green, blue));
g.drawString(tempStr, tempx, tempy);
tempx=(int)(tempx+(double)orgStringWight/(double)orgStringLength*rate);
}
setDrawLine(g, width, height);
}
private void setDrawLine(Graphics g,int width,int height){
Random random = new Random();
for (int i = 0; i < 60; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x, y, x + xl, y + yl);
}
}