本文實例講述了jsp實現簡單驗證碼的方法。分享給大家供大家參考。具體如下：
這里只有一個文件，可以在<img />的src屬性里直接調用顯示，適用于各種項目的表單安全驗證
jsp頁面代碼：
<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %><%!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);}%><%response.setHeader("Pragma","No-cache");response.setHeader("Cache-Control","no-cache");response.setDateHeader("Expires", 0);int width=60, height=20;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(0, 0, width, height);g.setFont(new Font("Times New Roman",Font.PLAIN,18)); g.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); g.drawLine(x,y,x+xl,y+yl);}String sRand="";for (int i=0;i<4;i++){ String rand=String.valueOf(random.nextInt(10)); sRand+=rand; g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110))); g.drawString(rand,13*i+6,16);}session.setAttribute("rand",sRand);g.dispose();ImageIO.write(image, "JPEG", response.getOutputStream());response.getOutputStream().flush();response.getOutputStream().close();out.clear();out=pageContext.pushBody();%>希望本文所述對大家的JSP程序設計有所幫助。
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