web项目中验证码的实现步骤

时间:2022-07-13 09:40:23
  1. 创建工具类:生成一个可成一张图片的工具类:代码如下(附录)可以直使用
  2. 创建另一个工具类:随机生成数字字母的组合:
    1. 代码如下:
package com.bjsxt.lc.util;
import java.util.Random;
public class RandomString
{
public static String randomCode(int size)
{
//用来存储验证码
StringBuffer code = new StringBuffer();
String sourceStr = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ";

Random random = new Random();
for(int i=0; i<size; i++)
{
code.append(sourceStr.charAt(random.nextInt(30))+"");
}
return code.toString();
}
//测试方法
public static void main(String[] args)
{
for(int i=0; i<40; i++)
{
String code = randomCode(4);
System.out.println(code);
}
}
}


3 创建action其中调用两个工具类
outputImage(int w, int h, OutputStream os, String code)方法,
    1. 参数说明:
      1. w:img的宽
      2. H:img的高
      3. os:img的输出流
      4. os:片上的验证码
    2. 创建一个action(struts2框架)
      1. 将os输出流直接堆到response.getOutputStream()上,输出到网页,这时应当将返回值置为空,
代码
package com.bjsxt.lc.action;

import java.io.IOException;

import org.apache.catalina.deploy.ContextResource;
import org.apache.struts2.ServletActionContext;

import com.bjsxt.lc.action.BasicAction;
import com.bjsxt.lc.util.RandomString;
import com.bjsxt.lc.util.VerifyCodeUtils;

/**
* 一些公共的Action
* @author Administrator
*
*/
public class CommonAction extends BasicAction
{
/**
*
*/
private static final long serialVersionUID = 1L;

/***
* 生成验证验
* @return
*/
public String veritfCode()
{
//logger.info("--veritfCode--");
String code = RandomString.randomCode(4);
request.getSession().setAttribute("code", code);
try
{
VerifyCodeUtils.outputImage(120,80,response.getOutputStream(),code);
} catch (Exception e)
{
logger.info("-------------------------");
e.printStackTrace();
}
return null;
}
}
4、在jsp页面中<img src="${%home%}">引用:
<div class="form-group">
<label for="email" class="col-sm-2 control-label">验证码</label>
<div class="col-sm-8">
<div class="input-group">
<span class="input-group-addon"> <a href="#" tabindex="-1"
onclick="return refreshCode('imgCode');">
<img id="imgCode" src="${pageContext.request.contextPath}/common_veritfCode.htm" onclick="" title="点击刷新验证码" width="75" height="20" />
</a>
</span> <input type="text" id="code" name="code" class="form-control"
placeholder="验证码">
</div>
</div>
</div>
5、添加js脚本,达到跟换验证码的效果:
function refreshCode(imgCode)
{
var dom = $("#"+imgCode);
dom.attr("src","/auth_mana1/common_veritfCode.htm?new="+new Date());
return false;
}

附录:生成随机验证图片的代码(从网上copy的)
  1. package com.bjsxt.lc.util;

    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.LinearGradientPaint;
    import java.awt.Paint;
    import java.awt.RenderingHints;
    import java.awt.geom.AffineTransform;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.Arrays;
    import java.util.Random;

    import javax.imageio.ImageIO;

    public class VerifyCodeUtils
    {

    // 使用到Algerian字体,系统里没有的话需要安装字体,字体只显示大写,去掉了1,0,i,o几个容易混淆的字符
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    private static Random random = new Random();

    /**
    * 使用系统默认字符源生成验证码
    *
    * @param verifySize
    * 验证码长度
    * @return
    */
    public static String generateVerifyCode(int verifySize)
    {
    return generateVerifyCode(verifySize, VERIFY_CODES);
    }

    /**
    * 使用指定源生成验证码
    *
    * @param verifySize
    * 验证码长度
    * @param sources
    * 验证码字符源
    * @return
    */
    public static String generateVerifyCode(int verifySize, String sources)
    {
    if (sources == null || sources.length() == 0)
    {
    sources = VERIFY_CODES;
    }
    int codesLen = sources.length();
    Random rand = new Random(System.currentTimeMillis());
    StringBuilder verifyCode = new StringBuilder(verifySize);
    for (int i = 0; i < verifySize; i++)
    {
    verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
    }
    return verifyCode.toString();
    }

    /**
    * 生成随机验证码文件,并返回验证码值
    *
    * @param w
    * @param h
    * @param outputFile
    * @param verifySize
    * @return
    * @throws IOException
    */
    public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException
    {
    String verifyCode = generateVerifyCode(verifySize);
    outputImage(w, h, outputFile, verifyCode);
    return verifyCode;
    }

    /**
    * 输出随机验证码图片流,并返回验证码值
    *
    * @param w
    * @param h
    * @param os
    * @param verifySize
    * @return
    * @throws IOException
    */
    public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException
    {
    String verifyCode = generateVerifyCode(verifySize);
    outputImage(w, h, os, verifyCode);
    return verifyCode;
    }

    /**
    * 生成指定验证码图像文件
    *
    * @param w
    * @param h
    * @param outputFile
    * @param code
    * @throws IOException
    */
    public static void outputImage(int w, int h, File outputFile, String code) throws IOException
    {
    if (outputFile == null)
    {
    return;
    }
    File dir = outputFile.getParentFile();
    if (!dir.exists())
    {
    dir.mkdirs();
    }
    try
    {
    outputFile.createNewFile();
    FileOutputStream fos = new FileOutputStream(outputFile);
    outputImage(w, h, fos, code);
    fos.close();
    } catch (IOException e)
    {
    throw e;
    }
    }

    /**
    * 输出指定验证码图片流
    *
    * @param w
    * @param h
    * @param os
    * @param code
    * @throws IOException
    */
    public static void outputImage(int w, int h, OutputStream os, String code) throws IOException
    {
    int verifySize = code.length();
    BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    Random rand = new Random();
    Graphics2D g2 = image.createGraphics();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    Color[] colors = new Color[5];
    Color[] colorSpaces = new Color[]
    { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE, Color.PINK,
    Color.YELLOW };
    float[] fractions = new float[colors.length];
    for (int i = 0; i < colors.length; i++)
    {
    colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
    fractions[i] = rand.nextFloat();
    }
    Arrays.sort(fractions);

    g2.setColor(Color.GRAY);// 设置边框色
    g2.fillRect(0, 0, w, h);

    Color c = getRandColor(200, 250);
    g2.setColor(c);// 设置背景色
    g2.fillRect(0, 2, w, h - 4);

    // 绘制干扰线
    Random random = new Random();
    g2.setColor(getRandColor(160, 200));// 设置线条的颜色
    for (int i = 0; i < 20; i++)
    {
    int x = random.nextInt(w - 1);
    int y = random.nextInt(h - 1);
    int xl = random.nextInt(6) + 1;
    int yl = random.nextInt(12) + 1;
    g2.drawLine(x, y, x + xl + 40, y + yl + 20);
    }

    // 添加噪点
    float yawpRate = 0.05f;// 噪声率
    int area = (int) (yawpRate * w * h);
    for (int i = 0; i < area; i++)
    {
    int x = random.nextInt(w);
    int y = random.nextInt(h);
    int rgb = getRandomIntColor();
    image.setRGB(x, y, rgb);
    }

    shear(g2, w, h, c);// 使图片扭曲

    g2.setColor(getRandColor(100, 160));
    int fontSize = h - 4;
    Font font = new Font("Algerian", Font.ITALIC, fontSize);
    g2.setFont(font);
    char[] chars = code.toCharArray();
    for (int i = 0; i < verifySize; i++)
    {
    AffineTransform affine = new AffineTransform();
    affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1),
    (w / verifySize) * i + fontSize / 2, h / 2);
    g2.setTransform(affine);
    g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
    }

    g2.dispose();
    ImageIO.write(image, "jpg", os);
    }

    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);
    int g = fc + random.nextInt(bc - fc);
    int b = fc + random.nextInt(bc - fc);
    return new Color(r, g, b);
    }

    private static int getRandomIntColor()
    {
    int[] rgb = getRandomRgb();
    int color = 0;
    for (int c : rgb)
    {
    color = color << 8;
    color = color | c;
    }
    return color;
    }

    private static int[] getRandomRgb()
    {
    int[] rgb = new int[3];
    for (int i = 0; i < 3; i++)
    {
    rgb[i] = random.nextInt(255);
    }
    return rgb;
    }

    private static void shear(Graphics g, int w1, int h1, Color color)
    {
    shearX(g, w1, h1, color);
    shearY(g, w1, h1, color);
    }

    private static void shearX(Graphics g, int w1, int h1, Color color)
    {

    int period = random.nextInt(2);

    boolean borderGap = true;
    int frames = 1;
    int phase = random.nextInt(2);

    for (int i = 0; i < h1; i++)
    {
    double d = (double) (period >> 1)
    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
    g.copyArea(0, i, w1, 1, (int) d, 0);
    if (borderGap)
    {
    g.setColor(color);
    g.drawLine((int) d, i, 0, i);
    g.drawLine((int) d + w1, i, w1, i);
    }
    }

    }

    private static void shearY(Graphics g, int w1, int h1, Color color)
    {

    int period = random.nextInt(40) + 10; // 50;

    boolean borderGap = true;
    int frames = 20;
    int phase = 7;
    for (int i = 0; i < w1; i++)
    {
    double d = (double) (period >> 1)
    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
    g.copyArea(i, 0, 1, h1, 0, (int) d);
    if (borderGap)
    {
    g.setColor(color);
    g.drawLine(i, (int) d, i, 0);
    g.drawLine(i, (int) d + h1, i, h1);
    }

    }

    }

    public static void main(String[] args) throws IOException
    {
    File dir = new File("F:/verifies");
    int w = 200, h = 80;
    for (int i = 0; i < 2; i++)
    {
    String verifyCode = generateVerifyCode(4);
    File file = new File(dir, verifyCode + ".jpg");
    outputImage(w, h, file, verifyCode);
    }
    }
    }