S2SH框架中的无刷新验证码功能实现

暑假期间在实验室做使用S2SH框架的项目，其中登录和注册需要验证码，实现了一个没有实现刷新验证码功能的简单版本，代码如下：

  1 package com.sem.action;
  2 
  3 import java.io.*;
  4 import java.util.Map;
  5 
  6 import javax.imageio.ImageIO;
  7 import javax.imageio.stream.ImageOutputStream;
  8 //import javax.servlet.http.HttpServletRequest;
  9 import javax.servlet.http.HttpServletResponse;
 10 
 11 //import org.apache.struts2.interceptor.ServletRequestAware;
 12 import org.apache.struts2.interceptor.ServletResponseAware;
 13 //import org.springframework.context.annotation.Scope;
 14 
 15 import com.opensymphony.xwork2.ActionContext;
 16 import com.opensymphony.xwork2.ActionSupport;
 17 
 18 import java.awt.*;
 19 import java.awt.image.BufferedImage;
 20 
 21 
 22 public class ImageCodeAction extends ActionSupport implements ServletResponseAware {
 23 
 24     private ByteArrayInputStream inputStream;
 25     private HttpServletResponse response;
 26 
 27     //生成4个0~9的随机数，放在一个字符串里
 28     public String createRandomString() {
 29         String str = "";
 30         for (int i = 0; i < 4; i++) {
 31             str += Integer
 32                     .toString((new Double(Math.random() * 10)).intValue());
 33         }
 34         return str;
 35     }
 36 
 37     //随机生成一种颜色
 38     public Color createsRandomColor() {
 39         int r = (new Double(Math.random() * 256)).intValue();
 40         int g = (new Double(Math.random() * 256)).intValue();
 41         int b = (new Double(Math.random() * 256)).intValue();
 42         return new Color(r, g, b);
 43     }
 44 
 45     //生成一个内存图片，将四个随机数写在图片上
 46     public BufferedImage createImage(String str) {
 47         int width = 60;
 48         int height = 20;
 49         BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
 50         //获取图形上下文
 51         Graphics g = image.getGraphics();
 52         //设定背景色
 53         g.setColor(Color.WHITE);
 54         g.fillRect(0, 0, width, height);
 55         //画边框
 56         g.setColor(Color.black);
 57         g.drawRect(0, 0, width - 1, height - 1);
 58         //将验证码显示到图像中
 59         g.setFont(new Font("Atlantic Inline", Font.PLAIN, 18));
 60         //使用随机颜色
 61         g.setColor(this.createsRandomColor());
 62         //将随机字符串的每个数字分别写到图片上
 63         g.drawString(Character.toString(str.charAt(0)), 8, 17);
 64         g.drawString(Character.toString(str.charAt(1)), 20, 17);
 65         g.drawString(Character.toString(str.charAt(2)), 33, 17);
 66         g.drawString(Character.toString(str.charAt(3)), 45, 17);
 67         //图像生效
 68         g.dispose();
 69         return image;
 70     }
 71 
 72     //将图片以字节形式写到InputStream里
 73     public ByteArrayInputStream createInputStream() throws Exception {
 74         //获取随机字符串
 75         String str = this.createRandomString();
 76         BufferedImage image = this.createImage(str);
 77         //将产生的字符串写入session，供校验时使用
 78         ActionContext actionContext = ActionContext.getContext();
 79         Map session = actionContext.getSession();
 80         session.put("random", str);
 81         System.out.print("str: " + str + "  session: " + (String)session.get("random") + "
");
 82         ByteArrayOutputStream output = new ByteArrayOutputStream();
 83         ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);
 84         ImageIO.write(image, "JPEG", imageOut);
 85         imageOut.close();
 86         ByteArrayInputStream input = new ByteArrayInputStream(output.toByteArray());
 87         output.close();
 88         return input;
 89     }
 90 
 91     //传入action后执行该方法生成图片验证码
 92     public String createCodeImage() throws Exception {
 93         response.setHeader("Pragma","No-cache"); 
 94         response.setHeader("Cache-Control","no-cache"); 
 95         response.setDateHeader("Expires", 0); 
 96         setInputStream(createInputStream());
 97         return SUCCESS;
 98     }
 99 
100     public ByteArrayInputStream getInputStream() {
101         return inputStream;
102     }
103 
104     public void setInputStream(ByteArrayInputStream inputStream) {
105         this.inputStream = inputStream;
106     }
107     
108     public void setServletResponse(HttpServletResponse response) {
109         this.response = response;
110     }
111 }

 如果想要实现刷新功能，利用JavaScript可以很容易做到。