Java工具类-验证码工具

1.工具类，生成随机验证码字符串

import java.util.Arrays;

/**
 * 工具类，生成随机验证码字符串
 *
 * @version 1.0
 * @author
 *
 */

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);
    }
    public static void main(String[] args) {
        SecurityCode code = new SecurityCode();
        System.out.println(getSecurityCode(6,SecurityCodeLevel.Hard,false));
    }
}

2.

package code;

import com.opensymphony.xwork2.ActionSupport;
import java.io.ByteArrayInputStream;
import java.util.Map;
import org.apache.struts2.interceptor.SessionAware;

/**
 * 提供图片验证码
 * @version 1.0 2012/08/22
 * @author dongliyang
 */
@SuppressWarnings("serial")
public class SecurityCodeImageAction extends ActionSupport implements SessionAware{

    //Struts2中Map类型的session
    private Map<String, Object> session;

    //图片流
    private ByteArrayInputStream imageStream;

    public ByteArrayInputStream getImageStream() {
        return imageStream;
    }

    public void setImageStream(ByteArrayInputStream imageStream) {
        this.imageStream = imageStream;
    }

    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
        session.put("SESSION_SECURITY_CODE", securityCode);
        return SUCCESS;
    }

    public void setSession(Map<String, Object> session) {
        this.session = session;
    }

}

3.

package code;

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;

/**
 * 工具类，生成验证码图片
 * @version 1.0 2012/08/21
 * @author dongliyang
 *
 */
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;
    }
}

4.

package code;

import java.io.IOException;
import java.io.PrintWriter;

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

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class CodeAction extends ActionSupport{
    HttpServletRequest request = ServletActionContext.getRequest();
    HttpSession session=request.getSession();
    HttpServletResponse response = ServletActionContext.getResponse();
   public String execute(){

    try {
         response.setContentType("text/html;charset=utf-8");
         request.setCharacterEncoding("utf-8");
         String validateC = (String) request.getSession().getAttribute("SESSION_SECURITY_CODE");
         System.out.println("validateC"+validateC);
         String veryCode = request.getParameter("code");
         System.out.println("c"+veryCode);
         PrintWriter out;
        out = response.getWriter();
        if(veryCode==null||"".equals(veryCode)){
               //response.sendRedirect(refer);
               out.print("验证码不能为空");
              System.out.println("验证码不能为空");
           } else{
            if(validateC.equals(veryCode)){              

                 out.print("验证码正确");
                   //request.getRequestDispatcher("ServletTo").forward(request, response);
                 System.out.println("验证码正确");
               }else{  

                   out.print("验证码错误");
                   System.out.println("验证码错误");
               }
           }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
       return null;
   }
}