一.创建RandomNum类

  1: import java.awt.Color;

  2: import java.awt.Font;

  3: import java.awt.Graphics;

  4: import java.awt.image.BufferedImage;

  5: import java.io.ByteArrayInputStream;

  6: import java.io.ByteArrayOutputStream;

  7: import java.io.IOException;

  8: import java.util.Random;

  9: import javax.imageio.ImageIO;

 10: import javax.imageio.stream.ImageOutputStream;

 11:

 12: public class RandomNumUtil {

 13:  private ByteArrayInputStream image; //字节流输出图像

 14:  private String str; //随机数组成的字符串

 15:

 16:  public void setImage(ByteArrayInputStream image) {

 17:   this.image = image;

 18:  }

 19:

 20:  public void setStr(String str) {

 21:   this.str = str;

 22:  }

 23:

 24:  private RandomNumUtil(){

 25:   init();//初始化属性

 26:  }

 27:  /*

 28:   * 取得RandomNumUtil实例

 29:   */

 30:  public static RandomNumUtil Instance() {

 31:   return new RandomNumUtil();

 32:  }

 33:  /*

 34:   * 取得验证码图片

 35:   */

 36:  public ByteArrayInputStream getImage() {

 37:   return image;

 38:  }

 39:  /*

 40:   * 取得图片的验证码

 41:   */

 42:  public String getStr() {

 43:   return str;

 44:  }

 45:  /*

 46:   * init()方法，为字节流赋值

 47:   */

 48:  private void init(){

 49:   //在内存中创建图像

 50:   int width=85,height=20;

 51:   BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

 52:   //获取图形上下文

 53:   Graphics g=image.getGraphics();

 54:   //生成随机类

 55:   Random random=new Random();

 56:   //设定背景色

 57:   g.setColor(getRandColor(200,250));

 58:   g.fillRect(0, 0, width, height);

 59:   //设定字体

 60:   g.setFont(new Font("Times New Roman",Font.PLAIN,18));

 61:   //随机产生155条干扰线，使图像中的认证码不易被其它程序探测到

 62:   g.setColor(getRandColor(160, 200));

 63:   for (int i = 0; i < 155; i++) {

 64:    int x=random.nextInt(width);

 65:    int y=random.nextInt(height);

 66:    int x1=random.nextInt(12);

 67:    int y1=random.nextInt(12);

 68:    g.drawLine(x, y, x+x1, y+y1);

 69:   }

 70:   //取随机产生的认证码（6位数）

 71:   String sRand="";

 72:   for (int i = 0; i < 6; i++) {

 73:    String rand=String.valueOf(random.nextInt(10));

 74:    sRand+=rand;

 75:    //将认证码显示到图像中

 76:    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));

 77:    //

 78:    g.drawString(rand, 13*i+6, 16);

 79:   }

 80:    //赋值验证码

 81:    this.str=sRand;

 82:    //图像生效

 83:    g.dispose();

 84:    ByteArrayInputStream input=null;

 85:    ByteArrayOutputStream output=new ByteArrayOutputStream();

 86:    try {

 87:     ImageOutputStream imageOut=ImageIO.createImageOutputStream(output);

 88:     ImageIO.write(image, "JPEG", imageOut);

 89:     imageOut.close();

 90:     input=new ByteArrayInputStream(output.toByteArray());

 91:    } catch (IOException e) {

 92:     System.out.println("验证码图片产生出现错误："+e.toString());

 93:     e.printStackTrace();

 94:    }

 95:    this.image=input;

 96:  }

 97:

 98:  /*

 99:   * 给定范围获得随机颜色

100:   */

101:  private Color getRandColor(int fc,int bc) {

102:   Random random = new Random();

103:   if(fc>255){

104:    fc=255;

105:   }

106:   if(bc>255){

107:    bc=255;

108:   }

109:   int r=fc+random.nextInt(bc-fc);

110:   int g=fc+random.nextInt(bc-fc);

111:   int b=fc+random.nextInt(bc-fc);

112:   return new Color(r, g, b);

113:  }

114: }

二.创建RandomAction

获取图像流，并放到sessio中

  1: package com.action;

  2:

  3: import java.io.ByteArrayInputStream;

  4:

  5: import com.opensymphony.xwork2.ActionContext;

  6: import com.opensymphony.xwork2.ActionSupport;

  7: import com.util.RandomNumUtil;

  8:

  9: public class RandomAction extends ActionSupport{

 10:  private ByteArrayInputStream inputStream;

 11:

 12:  public ByteArrayInputStream getInputStream() {

 13:   return inputStream;

 14:  }

 15:

 16:  public void setInputStream(ByteArrayInputStream inputStream) {

 17:   this.inputStream = inputStream;

 18:  }

 19:

 20:  public String execute() throws Exception{

 21:

 22:   RandomNumUtil rand=RandomNumUtil.Instance();

 23:   this.setInputStream(rand.getImage());

 24:   ActionContext.getContext().getSession().put("random", rand.getStr());// 取得随机字符串放入HttpSession

 25:

 26:   return "success";

 27:  }

 28: }

 29: 

三.配置Struts.xml

  1: <package name="random" extends="struts-default">
  2: 		<!-- Random验证码 -->
  3: 		<action name="rand" class="com.action.RandomAction">
  4: 			<result type="stream"> <!-- 以流类型返回结果 -->
  5: 				<param name="contentType">image/jpeg</param>
  6: 				<param name="inputName">inputStream</param>
  7: 			</result>
  8: 		</action>
  9: 	</package>

四.在登录页面添加

  1: <s:textfield label="验证码"  name="rand" size="6" />

  2:       <image src="rand.action"

  3:         onclick="changeValidateCode(this)" title="点击图片刷新验证码" />

五.在loginAction中添加验证码验证

  1: String random = (String) ActionContext.getContext().getSession().get("random");

  2:   if (random.equals(rand)) {

  3:

  4:   } else {

  5:

  6:   }