web之动态生成图片-登陆验证码

package image; import java.awt.BasicStroke; 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; import java.util.Random; import javax.imageio.ImageIO; public class VerifyCode { private int w = 70; private int h = 35; private Random r=new Random(); //字体库 // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"} private String[] fontNames= {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}; //可选字符 private String codes="1234567890qazwsxedcrfvtgbyhnujmikolpQAZWSXEDCRFVTGBYHNUJMIKLOP"; //背景色 private Color bgColor=new Color(255,255,255); //验证码上的文本 private String text; //生成随机的颜色 private Color randomColor() { int red=r.nextInt(150); int green=r.nextInt(150); int blue=r.nextInt(150); return new Color(red,green,blue); } //生成随机的字体(从字体库中选出) private Font randomFont() { //从字体库长度中选出一个随机数 int index=r.nextInt(fontNames.length); //生成随机字体的名称 String fontName=fontNames[index]; //生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体) int style=r.nextInt(4); //生成随机字号, 24 ~ 28 int size=r.nextInt(5)+24; return new Font(fontName,style,size); } //画干扰线 private void drawLine(BufferedImage image) { int num=4;//一共画4条干扰线 Graphics2D g2=(Graphics2D)image.getGraphics(); for(int i=0;i<num;i++) {//生成两个点的坐标，即4个值 int x1=r.nextInt(w); int y1=r.nextInt(h); int x2=r.nextInt(w); int y2=r.nextInt(h); g2.setStroke(new BasicStroke(1.5F)); g2.setColor(randomColor());//干扰线的颜色随机 g2.drawLine(x1, y1, x2, y2); } } //随机生成一个字符 private char randomChar() { int index=r.nextInt(codes.length()); return codes.charAt(index); } //创建BufferedImage private BufferedImage createImage() { BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB); Graphics2D g2=(Graphics2D)image.getGraphics(); g2.setColor(this.bgColor); g2.fillRect(0, 0, w, h); return image; } //调用这个方法得到验证码 public BufferedImage getImage() { //创建图片缓冲区 BufferedImage image=createImage(); //得到绘制环境 Graphics2D g2=(Graphics2D)image.getGraphics(); //用来装载生成的验证码文本 StringBuilder sb=new StringBuilder(); //向图片中画4个字符 for(int i=0;i<4;i++) {//循环4次，每次生成一个字符 String s=randomChar()+"";//随机生成一个字母 sb.append(s);//把字母添加到sb中 float x=i*1.0F*w/4;//设置当前字符的x轴坐标 g2.setFont(randomFont());//设置随机字体); g2.setColor(randomColor());//设置随机颜色 g2.drawString(s, x, h-5);//画图 } this.text=sb.toString();//把生成的字符串赋值给this.txt drawLine(image); return image; } // 返回验证码图片上的文本 public String getText () { return text; } // 保存图片到指定的输出流 public static void output (BufferedImage image, OutputStream out) throws IOException { ImageIO.write(image, "JPEG", out); } }