Gif验证码类
package com.paic.bics.common.utils.vcode; import java.awt.AlphaComposite; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; /** * <p>Gif验证码类</p> * @version:1.0 */ public class GifCaptcha extends Captcha { public GifCaptcha() { } public GifCaptcha(int width,int height){ this.width = width; this.height = height; } public GifCaptcha(int width,int height,int len){ this(width,height); this.len = len; } public GifCaptcha(int width,int height,int len,Font font) { this(width,height,len); this.font = font; } @Override public void out(OutputStream os) { try { GifEncoder gifEncoder = new GifEncoder(); // gif编码类,这个利用了洋人写的编码类,所有类都在附件中 //生成字符 gifEncoder.start(os); gifEncoder.setQuality(180); gifEncoder.setDelay(100); gifEncoder.setRepeat(0); BufferedImage frame; char[] rands =alphas(); Color fontcolor[]=new Color[len]; for(int i=0;i<len;i++) { fontcolor[i]=new Color(20 + num(110), 20 + num(110), 20 + num(110)); } for(int i=0;i<len;i++) { frame=graphicsImage(fontcolor, rands, i); gifEncoder.addFrame(frame); frame.flush(); } gifEncoder.finish(); }finally { try { os.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } /** * 画随机码图 * @param fontcolor 随机字体颜色 * @param strs 字符数组 * @param flag 透明度使用 * @return BufferedImage */ private BufferedImage graphicsImage(Color[] fontcolor,char[] strs,int flag) { BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB); //或得图形上下文 //Graphics2D g2d=image.createGraphics(); Graphics2D g2d = (Graphics2D)image.getGraphics(); //利用指定颜色填充背景 g2d.setColor(Color.WHITE); g2d.fillRect(0, 0, width, height); AlphaComposite ac3; int h = height - ((height - font.getSize()) >>1) ; int w = width/len; g2d.setFont(font); for(int i=0;i<len;i++) { ac3 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, getAlpha(flag, i)); g2d.setComposite(ac3); g2d.setColor(fontcolor[i]); g2d.drawOval(num(width), num(height), 5+num(10), 5+num(10)); g2d.drawString(strs[i]+"", (width-(len-i)*w)+(w-font.getSize())+1, h-4); } g2d.dispose(); return image; } /** * 获取透明度,从0到1,自动计算步长 * @return float 透明度 */ private float getAlpha(int i,int j) { int num = i+j; float r = (float)1/len,s = (len+1) * r; return num > len ? (num *r - s) : num * r; } }