java验证码

package com.bingyang.util;

import java.util.Arrays;  
/**  
  * 工具类，生成随机验证码字符串  
  *  
  */  
public class SecurityCode {  
        /**  
          * 验证码难度级别，Simple只包含数字，Medium包含数字和小写英文，Hard包含数字和大小写英文  
          */  
         public enum SecurityCodeLevel {Simple,Medium,Hard};  
           
         /**  
          * 产生默认验证码，4位中等难度  
         * @return  String 验证码  
         */  
        public static String getSecurityCode(){  
             return getSecurityCode(4,SecurityCodeLevel.Medium,false);  
         }  
        /**  
         * 产生长度和难度任意的验证码  
         * @param length  长度  
          * @param level   难度级别  
          * @param isCanRepeat  是否能够出现重复的字符，如果为true，则可能出现 5578这样包含两个5,如果为false，则不可能出现这种情况  
         * @return  String 验证码  
         */  
         public static String getSecurityCode(int length,SecurityCodeLevel level,boolean isCanRepeat){  
             //随机抽取len个字符  
             int len=length;  
               
             //字符集合(除去易混淆的数字0、数字1、字母l、字母o、字母O)  
             char[] codes={'1','2','3','4','5','6','7','8','9',  
                           'a','b','c','d','e','f','g','h','i','j','k','m','n','p','q','r','s','t','u','v','w','x','y','z',  
                           'A','B','C','D','E','F','G','H','I','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z'};  
               
             //根据不同的难度截取字符数组  
             if(level==SecurityCodeLevel.Simple){  
                 codes=Arrays.copyOfRange(codes, 0,9);  
             }else if(level==SecurityCodeLevel.Medium){  
                 codes=Arrays.copyOfRange(codes, 0,33);  
             }  
             //字符集合长度  
             int n=codes.length;  
              
             //抛出运行时异常  
             if(len>n&&isCanRepeat==false){  
                 throw new RuntimeException(  
                        String.format("调用SecurityCode.getSecurityCode(%1$s,%2$s,%3$s)出现异常，当isCanRepeat为%3$s时，传入参数%1$s不能大于%4$s",  
                                        len,level,isCanRepeat,n));  
            }  
            //存放抽取出来的字符  
             char[] result=new char[len];  
             //判断能否出现重复的字符  
            if(isCanRepeat){  
                 for(int i=0;i<result.length;i++){  
                     //索引 0 and n-1  
                     int r=(int)(Math.random()*n);  
                   
                     //将result中的第i个元素设置为codes[r]存放的数值  
                     result[i]=codes[r];  
                }  
             }else{  
                 for(int i=0;i<result.length;i++){  
                     //索引 0 and n-1  
                     int r=(int)(Math.random()*n);  
                      
                     //将result中的第i个元素设置为codes[r]存放的数值  
                     result[i]=codes[r];  
                       
                    //必须确保不会再次抽取到那个字符，因为所有抽取的字符必须不相同。  
                     //因此，这里用数组中的最后一个字符改写codes[r]，并将n减1  
                    codes[r]=codes[n-1];  
                    n--;  
                 }  
            }  
             return String.valueOf(result);  
        }  
}  

 

package com.bingyang.util;


import java.awt.Color;  
import java.awt.Font;  
import java.awt.Graphics;  
import java.awt.image.BufferedImage;  
import java.io.ByteArrayInputStream;  
import java.io.ByteArrayOutputStream;  
import java.io.IOException;  
import java.util.Random;  
import com.sun.image.codec.jpeg.ImageFormatException;  
import com.sun.image.codec.jpeg.JPEGCodec;  
import com.sun.image.codec.jpeg.JPEGImageEncoder;  
/**  
 * 验证码生成器类，可生成数字、大写、小写字母及三者混合类型的验证码。  
 * 支持自定义验证码字符数量；  
 * 支持自定义验证码图片的大小；  
 * 支持自定义需排除的特殊字符；  
 * 支持自定义干扰线的数量；  
 * 支持自定义验证码图文颜色  
 */  
public class SecurityImage {  
         /**  
           * 生成验证码图片  
           * @param securityCode   验证码字符  
           * @return  BufferedImage  图片  
          */  
         public static BufferedImage createImage(String securityCode){  
             //验证码长度  
             int codeLength=securityCode.length();  
             //字体大小  
            int fSize = 15;  
              int fWidth = fSize + 1;  
             //图片宽度  
             int width = codeLength * fWidth + 6 ;  
             //图片高度  
             int height = fSize * 2 + 1;  
              //图片  
              BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
              Graphics g=image.createGraphics();  
             //设置背景色  
              g.setColor(Color.WHITE);  
               //填充背景  
              g.fillRect(0, 0, width, height);  
               //设置边框颜色  
              g.setColor(Color.LIGHT_GRAY);  
               //边框字体样式  
              g.setFont(new Font("Arial", Font.BOLD, height - 2));  
               //绘制边框  
              g.drawRect(0, 0, width - 1, height -1);  
               //绘制噪点  
              Random rand = new Random();  
               //设置噪点颜色  
               g.setColor(Color.LIGHT_GRAY);  
               for(int i = 0;i < codeLength * 6;i++){  
                   int x = rand.nextInt(width);  
                   int y = rand.nextInt(height);  
                  //绘制1*1大小的矩形  
                   g.drawRect(x, y, 1, 1);  
               }  
              //绘制验证码  
             int codeY = height - 10;    
              //设置字体颜色和样式  
               g.setColor(new Color(19,148,246));  
               g.setFont(new Font("Georgia", Font.BOLD, fSize));  
               for(int i = 0; i < codeLength;i++){  
                   g.drawString(String.valueOf(securityCode.charAt(i)), i * 16 + 5, codeY);  
              }  
               //关闭资源  
               g.dispose();  
               return image;  
           }  
           /**  
           * 返回验证码图片的流格式  
           * @param securityCode  验证码  
            * @return ByteArrayInputStream 图片流  
            */  
           public static ByteArrayInputStream getImageAsInputStream(String securityCode){  
             BufferedImage image = createImage(securityCode);  
              return convertImageToStream(image);  
          }  
          /**  
            * 将BufferedImage转换成ByteArrayInputStream  
            * @param image  图片  
            * @return ByteArrayInputStream 流  
            */  
           private static ByteArrayInputStream convertImageToStream(BufferedImage image){  
             ByteArrayInputStream inputStream = null;  
              ByteArrayOutputStream bos = new ByteArrayOutputStream();  
             JPEGImageEncoder jpeg = JPEGCodec.createJPEGEncoder(bos);  
              try {  
                  jpeg.encode(image);  
                  byte[] bts = bos.toByteArray();  
                  inputStream = new ByteArrayInputStream(bts);  
             } catch (ImageFormatException e) {  
                  e.printStackTrace();  
         } catch (IOException e) {  
                 e.printStackTrace();  
             }  
             return inputStream;  
         }  
}  

访问的action

/**   
 * @FILE:RegisterAction.java   
 * @PACKAGE	:com.accp.action
 * @COPYRIGHT:copyright(c) 2013,Rights Reserved
 * @COMPANY	:	
 * @DESCIPTION:	
 * @AUTHOR:	吕兵阳
 * @VERSION:v1.0
 * @DATE:2013-12-15 上午9:46:04
 */
package com.bingyang.action;

import java.io.ByteArrayInputStream;
import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.apache.struts2.ServletActionContext;

import com.alibaba.fastjson.JSONObject;
import com.bingyang.util.SecurityCode;
import com.bingyang.util.SecurityImage;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

/**
 ***************************************************************
 * <p>
 * @CLASS:RegisterAction
 * @DESCRIPTION:	
 * @AUTHOR:吕兵阳
 * @VERSION:v1.0
 * @DATE:2013-12-15 上午9:46:04            
 * </p>  
 ****************************************************************
 */
public class RegisterAction extends ActionSupport{
	/**
	 * Logger for this class
	 */
	private static final Logger logger = Logger.getLogger(RegisterAction.class);

	 private static final long serialVersionUID = 1496691731440581303L;  
	    //图片流  
	    private ByteArrayInputStream imageStream; 
	    public ByteArrayInputStream getImageStream() {  
	        return imageStream;  
	    }  
	    public void setImageStream(ByteArrayInputStream imageStream) {  
	        this.imageStream = imageStream;  
	    }  
//	    @Action("imagecode")  
	    public String execute() throws Exception { 
	        //如果开启Hard模式，可以不区分大小写  
	        //String securityCode = SecurityCode.getSecurityCode(4,SecurityCodeLevel.Hard, false).toLowerCase();  
	        //获取默认难度和长度的验证码  
	        String securityCode = SecurityCode.getSecurityCode();
	        imageStream = SecurityImage.getImageAsInputStream(securityCode);  
	        //放入session中  
	        ActionContext.getContext().getSession().put("securityCode", securityCode);  
	        return SUCCESS;  
	    }
	    /**
	     * 验证验证码是否正确
	     * @throws IOException 
	     */
	    public void check() throws IOException{
	    	HttpServletResponse response = ServletActionContext.getResponse();
	    	HttpServletRequest request=ServletActionContext.getRequest();
	    	response.setContentType("text/html;charset=utf-8");
	    	String code=(String) ActionContext.getContext().getSession().get("securityCode");
	    	String inputCode=request.getParameter("param");
	    	JSONObject obj = new JSONObject();
	    	if(inputCode.equals(code)){
	    		obj.put("status", "y");
	    		obj.put("info", "正确！");
	    	}else{
	    		obj.put("status", "n");
	    		obj.put("info", "验证码输入错误！");
	    	}
	    	response.getWriter().write(obj.toJSONString());
	    	return;
	    	}
	    
}

struts2配置

<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
	"http://struts.apache.org/dtds/struts-2.1.7.dtd">
	<struts>
	<package name="default" namespace="/" extends="struts-default">
	<action name="register" class="com.bingyang.action.RegisterAction">
	<result name="success" type="stream">
		 <param name="contentType">image/jpeg</param>  
          <param name="inputName">imageStream</param>  
          <param name="bufferSize">2048</param>  
	</result>
	</action>
	</package>
	</struts>

jsp页面

<img src="register.action" onclick="this.src='register!execute.action?'+Math.random();"
								style="margin-left:5px;width:100px;" alt="看不清，换一张"/>