springMVC返回Base64位编码图片验证码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.util.Base64Utils;

public class VerfityCode {
      public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";//放到session中的key  
       //private String randString = "0123456789";//随机产生只有数字的字符串 private String  
       //private static String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生只有字母的字符串  
       private static String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生数字与字母组合的字符串  
       private static int width = 95;// 图片宽  
       private static int height = 25;// 图片高  
       private static int lineSize = 40;// 干扰线数量  
       private static int stringNum = 4;// 随机产生字符数量  

       private static Random random = new Random();  

       /* 
        * 获得字体 
        */  
       private static Font getFont() {  
           return new Font("Fixedsys", Font.CENTER_BASELINE, 18);  
       }  

       /* 
        * 获得颜色 
        */  
       private static Color getRandColor(int fc, int bc) {  
           if (fc > 255)  
               fc = 255;  
           if (bc > 255)  
               bc = 255;  
           int r = fc + random.nextInt(bc - fc - 16);  
           int g = fc + random.nextInt(bc - fc - 14);  
           int b = fc + random.nextInt(bc - fc - 18);  
           return new Color(r, g, b);  
       }  

       /** 
        * 生成随机图片 
        * @return 
        */  
       public static String getRandcode(HttpServletRequest request, HttpServletResponse response) {  
           HttpSession session = request.getSession();  
           // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类  
           BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);  
           Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作  
           g.fillRect(0, 0, width, height);  
           g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));  
           g.setColor(getRandColor(110, 133));  
           // 绘制干扰线  
           for (int i = 0; i <= lineSize; i++) {  
               drowLine(g);  
           }  
           // 绘制随机字符  
           String randomString = "";  
           for (int i = 1; i <= stringNum; i++) {  
               randomString = drowString(g, randomString, i);  
           }  
           //将生成的随机字符串保存到session中，而jsp界面通过session.getAttribute("RANDOMCODEKEY")，  
           //获得生成的验证码，然后跟用户输入的进行比较  
           session.removeAttribute(RANDOMCODEKEY);  
           session.setAttribute(RANDOMCODEKEY, randomString);  
           g.dispose();  
           try {  
               // 将内存中的图片通过流动形式输出到客户端  
               ImageIO.write(image, "JPEG", response.getOutputStream());  
           } catch (Exception e) {  
               e.printStackTrace();  
           }
         return randomString;  

       }  

       public static String[] getRandcode() {  
          byte[] bf = null;
           // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类  
           BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);  
           Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作  
           g.fillRect(0, 0, width, height);  
           g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));  
           g.setColor(getRandColor(110, 133));  
           // 绘制干扰线  
           for (int i = 0; i <= lineSize; i++) {  
               drowLine(g);  
           }  
           // 绘制随机字符  
           String randomString = "";  
           for (int i = 1; i <= stringNum; i++) {  
               randomString = drowString(g, randomString, i);  
           }  
           //将生成的随机字符串保存到session中，而jsp界面通过session.getAttribute("RANDOMCODEKEY")，  
           //获得生成的验证码，然后跟用户输入的进行比较  

           g.dispose();  
           try {  
               // 将内存中的图片通过流动形式输出到客户端  
               ByteArrayOutputStream out = new ByteArrayOutputStream();
               ImageIO.write(image, "JPEG", out);  

                bf = out.toByteArray();

           } catch (Exception e) {  
               e.printStackTrace();  
           }
         return new String[]{randomString,Base64Utils.encodeToString(bf)};  

       } 
       /* 
        * 绘制字符串 
        */  
       private static String drowString(Graphics g, String randomString, int i) {  
           g.setFont(getFont());  
           g.setColor(new Color(random.nextInt(101), random.nextInt(111), random  
                   .nextInt(121)));  
           String rand = String.valueOf(getRandomString(random.nextInt(randString  
                   .length())));  
           randomString += rand;  
           g.translate(random.nextInt(3), random.nextInt(3));  
           g.drawString(rand, 13 * i, 16);  
           return randomString;  
       }  

       /* 
        * 绘制干扰线 
        */  
       private static void drowLine(Graphics g) {  
           int x = random.nextInt(width);  
           int y = random.nextInt(height);  
           int xl = random.nextInt(13);  
           int yl = random.nextInt(15);  
           g.drawLine(x, y, x + xl, y + yl);  
       }  

       /* 
        * 获取随机的字符 
        */  
       public static String getRandomString(int num) {  
           return String.valueOf(randString.charAt(num));  
       }  

}