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