使用java生成字母验证码

来源：互联网发布：北师大网络信息门户编辑：程序博客网时间：2024/06/06 23:57

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 {
   //图片宽高
   private int w=70;
   private int h=35;
   private Random r=new Random();
   private String[] fontNames={"宋体","华文楷体","黑体","微软雅黑","楷体_GB2312"};
   private String codes="234567890qwertyuipasdfghjkzxcvbnmQWERTYUIPASDFGHJKZXCVBNM";
   private Color bgColor=new Color(255,255,255);
   private String text;
   //生成随机颜色
   private Color randomColor(){
       int red=r.nextInt(150);
       int green=r.nextInt(150);
       int blue=r.nextInt(150);
       return new Color(red, green, blue);
       }
   //生成随机字体
   private Font randomFont(){
       int index=r.nextInt(fontNames.length);
       String fontName=fontNames[index];
       int style=r.nextInt(4);//0 无 1 粗体 2 斜体 3 粗+斜
       int size=r.nextInt(5)+24; //生成随机字号 24~28
       return new Font(fontName, style, size);
   }
   //干扰线
   private void drowLine(BufferedImage image){
       //生成4条干扰线
       int num=4;
       Graphics2D bi=(Graphics2D) image.getGraphics();
       for (int i = 0; i < num; i++) {
           int x1=r.nextInt(w);
           int x2=r.nextInt(w);
           int y1=r.nextInt(h);
           int y2=r.nextInt(h);
           bi.setStroke(new BasicStroke(1.5F));
           bi.setColor(Color.BLUE);//干扰线色
           bi.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);
   }
   //图片缓冲区
   private BufferedImage createImage(){
       BufferedImage image=new BufferedImage(w, h, BufferedImage.TYPE_INT_BGR);
       Graphics2D bi=(Graphics2D) image.getGraphics();
       bi.setColor(this.bgColor);
       bi.fillRect(0, 0, w, h);
       return image;
   }
   //生成图片
   public BufferedImage getImage(){
       BufferedImage image=createImage();
       Graphics2D bi=(Graphics2D) image.getGraphics();
       StringBuilder sb=new StringBuilder();
       for (int i = 0; i <4; i++) {
           String string=randomChar()+"";
           sb.append(string);
           //每个字符占图片1/4宽
           float x=i*1.0F*w/4;
           //随机字体格式
           bi.setFont(randomFont());
           bi.setColor(randomColor());
           //把字写在图片适当处（h-6指图片距底部6个高度）
           bi.drawString(string, x, h-6);
       }
       this.text=sb.toString();
       drowLine(image);
       return image;
   }
   //返回得到的字体
   public String getText(){
       return text;
   }
   //把图片写入指定位置
   public static void output(BufferedImage image,OutputStream out){
       try {
           ImageIO.write(image, "JPG", out);
       } catch (IOException e) {
           e.printStackTrace();
       }
   }
}

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