jsp登录验证码功能实现

1.login.jsp:关键代码如下

<%@ taglib uri="/struts-tags"  prefix="s"%>

<script type="text/javascript">

/* 验证码*/
function change(){
var img= document.getElementById("checkImage");
img.src="checkImgAction?"+new Date().getTime();//防止缓存加上new Date
}
</script>

<tr>
  <th>验证码:</th>
 <td>
  <span class="fieldSet">
  <input type="text" id="checkcode" name="checkcode" class="text captcha" maxlength="4" autocomplete="off"/>
  <img id="checkImage" class="captchaImage" src="checkImgAction"onclick="change()" title="点击更换验证码"/>
  <label style="color: red"><s:actionerror/> </label>
  </span>
 </td>
</tr>

2.CheckImgAction 工具类

package com.coffee.action;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;


import javax.imageio.ImageIO;


import org.apache.struts2.ServletActionContext;


import com.opensymphony.xwork2.ActionSupport;


/**
 * 验证码程序
 * @author wang
 *
 */
public class CheckImgAction extends ActionSupport {


@Override
public String execute() throws Exception {
int width = 120;
int height = 30;
BufferedImage bufferedImage = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics graphics = bufferedImage.getGraphics();
graphics.setColor(getRandColor(200, 250));


graphics.fillRect(0, 0, width, height);


graphics.setColor(Color.WHITE);
graphics.drawRect(0, 0, width - 1, height - 1);


Graphics2D graphics2d = (Graphics2D) graphics;
graphics2d.setFont(new Font("宋体", Font.BOLD, 18));


String words = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";


Random random = new Random();
StringBuffer sb = new StringBuffer();
int x = 10;
for (int i = 0; i < 4; i++) {
graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
.nextInt(110), 20 + random.nextInt(110)));
int jiaodu = random.nextInt(60) - 30;
double theta = jiaodu * Math.PI / 180;


int index = random.nextInt(words.length());


char c = words.charAt(index);
sb.append(c);


graphics2d.rotate(theta, x, 20);
graphics2d.drawString(String.valueOf(c), x, 20);
graphics2d.rotate(-theta, x, 20);
x += 30;


}
//将色很成的验证码号码放到session,以便获取验证对比
ServletActionContext.getRequest().getSession()
.setAttribute("checkcode", sb.toString());

// 干扰线
graphics.setColor(getRandColor(160, 200));
int x1;
int x2;
int y1;
int y2;
for (int i = 0; i < 30; i++) {
x1 = random.nextInt(width);
x2 = random.nextInt(12);
y1 = random.nextInt(height);
y2 = random.nextInt(12);
graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
}


// 图片输出到浏览器
graphics.dispose();
ImageIO.write(bufferedImage, "jpg", ServletActionContext.getResponse()
.getOutputStream());


return NONE;
}


/**
* 获取随机颜色
*/
private Color getRandColor(int fc, int bc) {
Random random = new Random();
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);
}
}

3.userAction验证验证码:

// 验证码输入框名称,自动封装
private String checkcode;

        public void setCheckcode(String checkcode) {
this.checkcode = checkcode;
}

// 登录校验
@InputConfig(resultName = "loginInput")
public String login() {
User user_ = userService.login(user);


String code = (String) ServletActionContext.getRequest().getSession()
.getAttribute("checkcode");
if (checkcode == null || !checkcode.equalsIgnoreCase(code)) {
this.addActionError("验证码错误!");
return "loginInput";


}
if (user_ != null) {
// 登录成功
ServletActionContext.getRequest().getSession()
.setAttribute("user_", user_);
return "loginSuccess";


} else {
// 登录失败
this.addActionMessage("用户名或密码错误或用户未激活");
return "loginInput";
}

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