jsp 登陆页面验证码的实现

package com.echo.autorent.comm.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import javax.imageio.ImageIO; import org.apache.commons.lang.RandomStringUtils; /** * <p>Title: Auto project</p> * * <p>Description: auto project for Hongma</p> * * <p>Copyright: Copyright (c) 2007</p> * * <p>Company: echo</p> * * @author echo * @version 1.0 */ public class RandomImageGenerator { //随即生成包含验证码的字符串 public static String random() { //20060320 add by wyx //因为o和0,l和1很难区分,所以,去掉大小写的o和l String str = ""; str = "2345689ABCDEFGHJKLMNPQRSUVWXYZabcdefhikmnrstuvwxz"; //初始化种子 return RandomStringUtils.random(6, str); //返回6为的字符串 } //随即生成包含验证码的字符串 public static String shortRandom() { //20060320 add by wyx //因为o和0,l和1很难区分,所以,去掉大小写的o和l String str = ""; str = "2345689ABCDEFGHJKLMNPQRSUVWXYZabcdefhikmnrstuvwxz"; //初始化种子 return RandomStringUtils.random(4, str); //返回6为的字符串 } /** * 根据要求的数字生成图片,背景为白色,字体大小16,字体颜色黑色粗体 * @param num 要生成的数字 * @param out 输出流 * @throws IOException */ public static void render(String num, OutputStream out) throws IOException { if (num.getBytes().length > 6) { throw new IllegalArgumentException( "The length of param num cannot exceed 6."); } //设定宽度和高度 int width = 130; int height = 18; // 在内存中创建图象 BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics2D g = (Graphics2D) bi.getGraphics(); //画边框 java.util.Random random = new java.util.Random(); g.setColor(Color.white); g.fillRect(0, 0, width, height); //设置字体 Font mFont = new Font("Arial", Font.PLAIN, 18); g.setFont(mFont); g.setColor(Color.BLACK); //设置字体颜色 //画认证码,每个认证码在不同的水平位置 String str1[] = new String[6]; for (int i = 0; i < str1.length; i++) { str1[i] = num.substring(i, i + 1); int w = 0; int x = (i + 1) % 3; //随即生成验证码字符的水平偏移量 if (x == random.nextInt(3)) { w = 14 - random.nextInt(2); } else { w = 14 + random.nextInt(2); } //随即生成颜色 Color color1 = new Color(random.nextInt(60), random.nextInt(60), random.nextInt(60)); g.setColor(color1); g.drawString(str1[i], 20 * i + 10,w); } 随机产生干扰点,并用不同的颜色表示，使图象中的认证码不易被其它程序探测到 for (int i = 0; i < 100; i++) { int x = random.nextInt(width); int y = random.nextInt(height); Color color1 = new Color(random.nextInt(55) + 200, random.nextInt(55) + 200, random.nextInt(55) + 200); g.setColor(color1); //随即画各种颜色的点 g.drawOval(x, y, 0, 0); } //画干扰线 for (int i = 0; i < 5; i++) { int x = random.nextInt(width); int y = random.nextInt(height); int x1 = random.nextInt(width); int y1 = random.nextInt(height); Color color1 = new Color(random.nextInt(55) + 200, random.nextInt(55) + 200, random.nextInt(55) + 200); g.setColor(color1); //随即画各种颜色的线 g.drawLine(x, y, x1, y1); } //图像生效 g.dispose(); //输出页面 ImageIO.write(bi, "jpg", out); } /** * 根据要求的数字生成图片,背景为白色,字体大小16,字体颜色黑色粗体 * @param num 要生成的数字 * @param out 输出流 * @throws IOException */ public static void shortRender(String num, OutputStream out) throws IOException { if (num.getBytes().length > 4) { throw new IllegalArgumentException( "The length of param num cannot exceed 4."); } //设定宽度和高度 int width = 64; int height = 18; // 在内存中创建图象 BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics2D g = (Graphics2D) bi.getGraphics(); //画边框 java.util.Random random = new java.util.Random(); g.setColor(Color.white); g.fillRect(0, 0, width, height); //设置字体 Font mFont = new Font("Arial", Font.PLAIN, 18); g.setFont(mFont); g.setColor(Color.BLACK); //设置字体颜色 //画认证码,每个认证码在不同的水平位置 String str1[] = new String[4]; for (int i = 0; i < str1.length; i++) { str1[i] = num.substring(i, i + 1); int w = 0; int x = (i + 1) % 3; //随即生成验证码字符的水平偏移量 if (x == random.nextInt(3)) { w = 14 - random.nextInt(2); } else { w = 14 + random.nextInt(2); } //随即生成颜色 Color color1 = new Color(random.nextInt(60), random.nextInt(60), random.nextInt(60)); g.setColor(color1); g.drawString(str1[i], 16 * i + 4,w); } // 随机产生干扰点,并用不同的颜色表示，使图象中的认证码不易被其它程序探测到 // for (int i = 0; i < 100; i++) { // int x = random.nextInt(width); // int y = random.nextInt(height); // Color color1 = new Color(random.nextInt(55) + 200, random.nextInt(55) + 200, // random.nextInt(55) + 200); // g.setColor(color1); //随即画各种颜色的点 // g.drawOval(x, y, 0, 0); // } // //画干扰线 // for (int i = 0; i < 5; i++) { // int x = random.nextInt(width); // int y = random.nextInt(height); // int x1 = random.nextInt(width); // int y1 = random.nextInt(height); // Color color1 = new Color(random.nextInt(55) + 200, random.nextInt(55) + 200, // random.nextInt(55) + 200); // // g.setColor(color1); //随即画各种颜色的线 // g.drawLine(x, y, x1, y1); // } //图像生效 g.dispose(); //输出页面 ImageIO.write(bi, "jpg", out); } public static void main(String[] args) throws IOException { String num = shortRandom(); System.out.println(num); shortRender(num, new FileOutputStream("D:\\test.jpg")); System.out.println("Image generated."); } }