vcode.jsp驗證碼

要用時把它當做一個圖片去引用就ok   <img src="images/code/vcode.jsp" ">

 

 

<%@ page contentType="image/jpeg"%><br /><%@ page import="java.awt.*" %><br /><%@ page import="java.awt.image.*" %><br /><%@ page import="java.util.*" %><br /><%@ page import="javax.imageio.*" %><br /><%@ page import="java.io.OutputStream"%></p><p><%!<br />Color getRandColor(int fc,int bc){//給定範圍獲得隨機顏色<br /> Random random = new Random();<br /> if(fc>255) fc=255;<br /> if(bc>255) bc=255;<br /> int r=fc+random.nextInt(bc-fc);<br /> int g=fc+random.nextInt(bc-fc);<br /> int b=fc+random.nextInt(bc-fc);<br /> return new Color(r,g,b);<br /> }<br />%><br /><%<br />//設定頁面不緩衝<br />response.setHeader("Pragma","No-cache");<br />response.setHeader("Cache-Control","no-cache");<br />response.setDateHeader("Expires", 0);</p><p>// 在記憶體中建立圖象<br />int width=60, height=20;<br />BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);</p><p>// 擷取圖形上下文<br />Graphics g = image.getGraphics();</p><p>//產生隨機類<br />Random random = new Random();</p><p>// 設定背景色<br />g.setColor(getRandColor(200,250));<br />g.fillRect(0, 0, width, height);</p><p>//設定字型<br />g.setFont(new Font("Times New Roman",Font.PLAIN,18));</p><p>// 隨機產生155條幹擾線，使圖象中的認證碼不易被其它程式探測到<br />g.setColor(getRandColor(160,200));<br />for (int i=0;i<155;i++)<br />{<br />int x = random.nextInt(width);<br />int y = random.nextInt(height);<br /> int xl = random.nextInt(12);<br /> int yl = random.nextInt(12);<br />g.drawLine(x,y,x+xl,y+yl);<br />}</p><p>// 取隨機產生的認證碼(4位元字)<br />String sRand="";<br />for (int i=0;i<4;i++){<br /> String rand=String.valueOf(random.nextInt(10));<br /> sRand+=rand;<br /> // 將認證碼顯示到圖象中<br /> g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));<br />//調用函數出來的顏色相同，可能是因為種子太接近，所以只能直接產生<br /> g.drawString(rand,13*i+6,16);<br />}</p><p>// 將認證碼存入session中<br />session.setAttribute("rand",sRand);</p><p>// 繪製圖象<br />g.dispose();</p><p>OutputStream os = response.getOutputStream();<br />// 輸出圖象到頁面<br />ImageIO.write(image, "JPEG",os);</p><p>//清空Jsp的out對象,避免servelet裡的out對象和上面的response.getOutputStream發生衝突<br />out.clear();<br />out = pageContext.pushBody();</p><p>%><br />