使用java生成字母验证码

本文实例为大家分享了java生成字母验证码的具体代码，供大家参考，具体内容如下

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();
   }
 }
}