struts生成登录验证码

来源：互联网发布：南宁java培训编辑：程序博客网时间：2024/06/06 15:40

1.先用servlet生成验证图片 servlet/AuthImg.java代码如下

package servlet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.ImageIO;

public class AuthImg extends HttpServlet {

private static int WIDTH = 60;
private static int HEIGHT = 25;
public void doGet(HttpServletRequest request, HttpServletResponse response) {
        try{
    HttpSession session = request.getSession();
    response.setContentType("image/jpeg");
    ServletOutputStream sos = response.getOutputStream();
    // 设置浏览器不要缓存此图片
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    // 创建内存图象并获得其图形上下文
    BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
      BufferedImage.TYPE_INT_RGB);
    Graphics g = image.getGraphics();
    // 产生随机的认证码
    char[] rands = generateCheckCode();
    // 产生图像
    drawBackground(g);
    drawRands(g, rands);
    // 结束图像的绘制过程，完成图像
    g.dispose();
    // 将图像输出到客户端
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ImageIO.write(image, "JPEG", bos);
    byte[] buf = bos.toByteArray();
    response.setContentLength(buf.length);
    // 下面的语句也可写成： bos.writeTo(sos);
    sos.write(buf);
    bos.close();
    sos.close();
    // 将当前验证码存入到 Session 中
    session.setAttribute("check_code", new String(rands));
    // 直接使用下面的代码将有问题， Session 对象必须在提交响应前获得
    // request.getSession().setAttribute("check_code",new String(rands));
        }catch(Exception e){
         e.printStackTrace();
        }
}
/**
   * 定义验证码的字符表
   * @return
   */
private char[] generateCheckCode() {
   String chars = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
   char[] rands = new char[4];
   for (int i = 0; i < 4; i++) {
    int rand = (int) (Math.random() * 61);
    rands[i] = chars.charAt(rand);
   }
   return rands;
}
     /**
      * 划出随机数值
      * @param
      * @param rands
      */
private void drawRands(Graphics g, char[] rands) {
   g.setColor(Color.BLUE);
   g.setFont(new Font(null, Font.PLAIN | Font.PLAIN, 18));
   g.drawString("" + rands[0], 1, 17);
   g.drawString("" + rands[1], 16, 15);
   g.drawString("" + rands[2], 31, 18);
   g.drawString("" + rands[3], 46, 16);
   //System.out.println(rands);
}
     /**
      * 画图片背景
      * @param g
      */
private void drawBackground(Graphics g) {
   g.setColor(new Color(0xDCDCDC));
   g.fillRect(0, 0, WIDTH, HEIGHT);
   // 随机产生 120 个干扰点
   for (int i = 0; i < 120; i++) {
    int x = (int) (Math.random() * WIDTH);
    int y = (int) (Math.random() * HEIGHT);
    int red = (int) (Math.random() * 255);
    int green = (int) (Math.random() * 255);
    int blue = (int) (Math.random() * 255);
    g.setColor(new Color(red, green, blue));
    g.drawOval(x, y, 1, 0);
   }
}
/**
   * 验证用户输入的验证码
   *
   *       */
public boolean checkLook(HttpServletRequest request, HttpServletResponse response,String check){
    response.setContentType("text/html;charset=GB2312");
    try{
           PrintWriter out = response.getWriter();
           HttpSession session = request.getSession(false);
           check = check.toLowerCase();    //这里把用户输入的验证码转换成小写
           if(session == null)
               return false;
           String savedCode = (String)session.getAttribute("check_code");
           savedCode = savedCode.toLowerCase(); //这里把存到session里的值转换成小写
           if(savedCode == null)
                return false;
           if(!savedCode.equals(check))
                return false;
    }catch(Exception e){
     e.printStackTrace();
    }
    return true;
}
}

2.编写com/struts/forms/ LoginForm.java代码如下：

package com.struts.forms;
import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
public class LoginForm extends ActionForm
{
     /**loginForm
      * @bob
      */
       private String username;
       private String password;
       private String checknum;
public String getUsername() {
  return username;
}
  public String getChecknum() {
  return checknum;
}
public void setChecknum(String checknum) {
  this.checknum = checknum;
}

}

3.编写com/struts/actions/LoginFormAction.java代码如下

package com.struts.actions;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.struts.forms.LoginForm;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionMessage;
import servlet.AuthImg;
public class LoginFormAction extends Action
{

/**用户登录判断
* @bob
*/
public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response)
   throws Exception
   {
  LoginForm loginForm=(LoginForm)form;
          String checknum=loginForm.getChecknum();
    if(checknum==null||"".equals(checknum))
    {
     request.setAttribute("login_form_checknum","请输入验证码！");
     return mapping.findForward("error");
    }
    else
    { AuthImg img=new AuthImg();
     if(img.checkLook(request, response, checknum)==false)
     {
      request.setAttribute("login_form_checknum", "验证码错误！");
      request.getSession(false).removeAttribute("check_code");
               return mapping.findForward("error");
     }
     }

}

}

4.web.xml的配置

<servlet>
<servlet-name>AuthImg</servlet-name>
<servlet-class>servlet.AuthImg</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AuthImg</servlet-name>
<url-pattern>/AuthImg</url-pattern>
</servlet-mapping>

5.struts-config.xml配置

<form-beans>
<form-bean name="loginForm" type="com.struts.forms.LoginForm"/>
</form-beans>

  <action-mappings>
<action path="/login"
          name="loginForm"
          type="com.struts.actions.LoginFormAction"
           validate="false"
          input="login.jsp"
>
<forward name="error" path="/login.jsp"/>

</action>
</action-mappings>

6.login.jsp部分代码如下

   <tr>
       <td>验证码</td><td><input type="text" name="checknum" size="10"/><img src="AuthImg"/></td>   *注意此处为你在web.xml配置的映射路径，此处显示图片
       <td><font color="red">${login_form_checknum}</font></td>
       </tr>
       <tr>
       <td><input type="submit" value="提交"></td>
       <td><input type="reset" value="重置"></td>

</tr>